CFMM Logo
BrainsCAN Logo

Brain Function and Connectivity

There is an accomplished group of investigators probing the fine-grained structure and organization of cortical substrates for sensorimotor control, multisensory integration for action, and the networks for the autonomic control of cardiovascular responses. These studies need millimeter resolution MRI and fMRI in humans at 3T and sub-millimeter resolution in humans at 7T. Therefore SNR is pushed to the limit. In addition, a variety of electrophysiological and physiological recording and stimulating techniques as well as pharmacological and cooling inactivation techniques will be simultaneously used with these MRI studies.  These studies will establish methodologies and model systems that are important for the understanding of patient groups. Improvements in intensive care have lead to an increase in the number of patients who survive severe brain injury. Some have a good prognosis, but many progress to a vegetative (VS) or minimally conscious state (MCS).

CFREF BrainsCAN Supported Studies

2019


Anaesthesia
PI: Pruszynski, Andrew

Department: Robarts Research

Award Value: Reduced Scanning Rate

The purpose of this project is to understand how different types of anesthesia affect evoked BOLD responses in processing in sensory and cognitive areas of brain using non-human primates as a model. Many investigations have been done on resting state function in anesthetized monkeys and these have been very informative about the functional connectivity of brain areas in various situations (e.g. after a stroke or during motor learning). However, there have been very few studies looking at how processing of incoming sensory inputs is modified by anethesia. Finding this out is important as training awake monkeys to enter the scanner is very challenging, often taking 1-2 years, and monkeys offer the possibility of doing much more invasive experiments to figure out the underlying neural mechanisms of sensory processing and cognitive function. The appropriate anesthetic protocol is crucial for expanding our ability to answer these questions.

In this study we will systematically compare anesthetic protocols in terms of how they effect somatosensory and visually evoked BOLD activity.

Separating conceptual and contextual information in the parahippocampal cortex
PI: Goodale, Mel

Department: Robarts Research

Award Value: Reduced Scanning Rate

Parahippocampal cortex (PHC) is a medial temporal lobe region involved in many cognitive processes, from perception of scenes and landmarks to associative and source memory. Damage to PHC can lead to impairments in processing spatial relations between objects, such as topographical agnosia (problems in way-finding). Despite a large body of research on the PHC, its precise function remains unclear. Our project aims at resolving an outstanding debate about the function of PHC and its role in context perception, improving our understanding of its function and dysfunction.

Two sets of studies have shown that the PHC is involved in context perception, and also represents conceptual similarity of objects. One explanation that may be able to reconcile these findings is that conceptually similar objects often appear in similar context (e.g., a toaster and a juicer can both be used for preparing breakfast, and both are usually found in the kitchen). This project aims to disentangle contextual and conceptual object features to probe object representations in the PHC. To what extent does conceptual similarity of PHC object representations reflect contextual co-occurrence of objects? In order to do this, we have developed a stimulus set in which these two types of features are orthogonalized. We selected the stimuli that typically occur within a specific context (i.e. beach, farm, etc.), while also belonging to distinct categories (i.e. vehicles, animals, clothing, etc.) This design allows us to determine whether PHC represents objects mainly based on their conceptual similarity (category), or based on their contextual co-occurrence, or a combination of the two. We are planning to run two sessions of this experiment using both picture and word stimuli. In PHC literature, both of these modalities are commonly used, and our aim is to replicate and reconcile previous findings.

Revisiting Mental Chronometery with Ultrafast fMRI
PI: Menon, Ravi

Department: Robarts Research

Award Value: Reduced Scanning Rate

The temporal aspects of hierarchical processing involved nt he mental process are termed "mental chroometry". It has bee shown previously that faster samplng,achieved by scanning onlyn a single or a small number of EPI slices found differences in the BoLD onset times across different brain areas in the order of hundreds of milliseconds (Menon et al, 1998). In the study previosly, conductd by Menon, the authors foud BOLD response in the motor planning areas correlated with behavoioral reaction times. The purpos of this project is to have a faster sampling rate, with full brin coverage using visual motor assoication task to distiguish between interregioal BOLD onset differences deendingon the task.

This will be a vaery valuable method to examine th tmporal evolution of the various ocmponents of cognitive processing by combining bhavioral masures with ultra-fst fMRI. It will help shed light on t he order and role of differnt cortical areas int he processing of cognitive information.

The reduced rate will allow us to greatly expand the nmber of subjects as we are planning to scan same subjects multiple times to reduce within subject reliability and increase the validity of our methods with the expectation that this would lead to publications in a higher impact journals. As the temporal resolution of this study is quite high <200 ms we might haved to discard some subjects due to motio which can lead to noisy reference scans which we are using with high acceleration factors. The reduced rate will allow us to take into account these overheads.

Separating conceptual and contextual information in the parahippocampal cortex
PI: Goodale, Mel

Department: Robarts Research

Award Value: Reduced Scanning Rate

Parahippocampal cortex (PHC) is a medial temporal lobe region involved in many cognitive processes, from perception of scenes and landmarks to associative and source memory. Damage to PHC can lead to impairments in processing spatial relations between objects, such as topographical agnosia (problems in way-finding). Despite a large body of research on the PHC, its precise function remains unclear. Our project aims at resolving an outstanding debate about the function of PHC and its role in context perception, improving our understanding of its function and dysfunction.

Two sets of studies have shown that the PHC is involved in context perception, and also represents conceptual similarity of objects. One explanation that may be able to reconcile these findings is that conceptually similar objects often appear in similar context (e.g., a toaster and a juicer can both be used for preparing breakfast, and both are usually found in the kitchen). This project aims to disentangle contextual and conceptual object features to probe object representations in the PHC. To what extent does conceptual similarity of PHC object representations reflect contextual co-occurrence of objects? In order to do this, we have developed a stimulus set in which these two types of features are orthogonalized. We selected the stimuli that typically occur within a specific context (i.e. beach, farm, etc.), while also belonging to distinct categories (i.e. vehicles, animals, clothing, etc.) This design allows us to determine whether PHC represents objects mainly based on their conceptual similarity (category), or based on their contextual co-occurrence, or a combination of the two. We are planning to run two sessions of this experiment using both picture and word stimuli. In PHC literature, both of these modalities are commonly used, and our aim is to replicate and reconcile previous findings.

Reading Pathways
PI: Joanisse, Marc

Department: BMI

Award Value: Reduced Scanning Rate

The current project investigates the contribution of the supramarginal gyrus (SMG) and the posterior middle temporal gyrus (pMTG) in word reading. The project utilizes Transcranial Magnetic Stimulation (TMS) to probe the functional contribution of these areas while participants read words. Such a paradigm can inform not only on the functional necessity of these areas but also the time-window in which they are necessary for word reading. Due to individual differences in brain structure and gyrification each participant will vary in where the target site lies in hers/his brain. Sack et al. (2009) compared the different localization methods for TMS and found the following results: fMRI-guided TMS yielding the strongest effect (d=1.13), followed by MRI-guided TMS (d=0.82), group Talairach coordinates (d=0.67) and 10-20 system (d=0.34). Having participants' individual sructural scans allows for a greater chance of seeing a significant effect if there is one. It also allows better control of what is actually being stimulated.

Since pMTG and SMG are actually quite close to each other and a TMS pulse has a radius of 8-10mm, it's beneficial to use individual brain scans to avoid this confound and mark target sites on a subjective basis. The structural scans would therefore benefit the current research project, making the results more solid and less confounded. The fundamental knowledge from this research provides valuable spatial and temporal coordinates of different processes involved in word reading. This knowledge would serve clinicians dealing with pure alexia, dyslexia, aphasias and other reading related defecits induced my stroke or brain injury.

Spoken Stories
PI: Johnsrude, Ingrid

Department: BMI

Award Value: Reduced Scanning Rate

The goal of this research is to understand how individuals engage with natural spoken stories under different listening challenges as individuals age and develop hearing impairment. Hearing problems are common among older adults and are particularly apparent in noisy situations such as a busy restaurant. Hearing impairment puts the people affected at risk of social isolation and cognitive decline. Research thus far has almost exclusively utilized artificial approaches, such as presenting isolated sentences without context, that are not personally relevant and are usually boring. In real life, materials follow some topical narrative and a listener is intrinsically motivated to comprehend. Using artificial approaches may not tap into the mechanisms involved during real-world listening. Here, we explore how individuals listen to engaging spoken stories under different listening challenges to obtain a better understanding of how people listen in real life, and to characterize the factors that contribute to failures of listening engagement as individuals age.

It involves imaging and behavior to investigate the neural dynamics during listening to spoken stories under different challenges (e.g., added background noise). This work is a crucial first step to understand the listening challenges older people and people with hearing impairment experience with real-world materials. The novel analyses techniques, such as inter-subject correlation analyses, applied here may help in the future to better identify people with hearing difficulty.

Consensus acquisition protocol for quantitative MRI of the spinal cord
PI: Dr Duggal, Neil

Department: Robarts Research

Award Value: Reduced Scanning Rate

Drs. Duggal and Bartha have spent over a decade demonstrating how injuries to the spinal cord affect the brain. Further work is necessary to investigate the links between brain and spinal cord dysfunction, but this is dependent on our ability to image the spinal cord. The cord has traditionally been technically challenging to image, mainly due to difficulties related to the need for high resolution and the presence of motion and susceptibility artifacts. Recently, an initiative brought together spinal cord imaging experts to develop a consensus acquisition protocol. Our group is participating in a global multi-centre study that will finalize the protocol and evaluate its reproducibility across different scanners.

A public repository of spinal cord images will also be created, giving researchers a way to determine normal values and variability in a healthy population. The development of a standard imaging protocol for the spinal cord will help to advance the study of a variety of neurological disorders.

Motivational consequences of metacognitive memory experiences
PI: Kohler, Stefan

Department: BMI

Award Value: Reduced Scanning Rate

In this project we are exploring the behavioural and neural consequences of the metacognitive experiences that accompany complete or partial memory retrieval failure. Namely, we are interested in why some memory cues result in a greater desire to remember the relevant information compared to others (i.e. when you see someone you know but can’t remember their name, you want to know the name more than you would for someone you've never met). We will relate later effort expended by participants to seek out the missing information to their earlier metacognitive experience (from the time of attempted retrieval). Further, we will investigate the neural correlates of these experiences (in medial temporal structures) and whether the relationship between metacognitive experience and information seeking is mediated by the engagement of areas associated with reward/motivation, including the VTA, nucleus accumbens, etc. These findings will significantly expand our knowledge about what happens when we fail to successfully retrieve a memory.

We will use fMRI methods to investigate consequences of memory failure and the metacognitive experiences that accompany them that go beyond the typical focus of most current research in the field. This will provide a better understanding of the link between various brain structures and the behavioral consequences of failed memory retrieval. As our regions of interest are key reward nuclei within the dopaminergic circuit, they are heavily impacted by degeneration during Parkinson's Disease, thus revealing the consequences of memory decisions on activity here may lead us to a greater understanding of the impact of PD in the domain of memory consequences.

FMRI and TMS Experiments on the Visuomotor System
PI: Goodale, Mel

Department: BMI

Award Value: Reduced Scanning Rate

This project is part of a larger international collaboration funded by the Australian Research Council between investigators at Western University and La Trobe University that aims to determine how we select actions to visual cues in a rapid, unconscious, and automatic manner. Learning associations between visual stimuli and motor responses is part of normal development and continues throughout life. The rapid deployment of these actions is often critical for our safety yet we have limited knowledge of how the human brain does this. At Western University, we will use fMRI and TMS to characterise the spatial and temporal neural architecture underlying these processes and determine how the dorsal and ventral streams of visual processing, each specialised for motor control and recognition respectively, interact in vision-based actions as these actions become learned. The cognitive and biological principles emerging from these experiments will provide new frameworks for driving improvement in any domain in which goal-directed actions depend on the rapid processing of visual information for directing actions, such as human-machine interfaces.

Knowledge acquired from these experiments will also have implications for understanding and treating numerous clinical neurological conditions in which there are impairments in how vision is used for perception (e.g. visual agnosia) and action (e.g. optic ataxia, apraxia). A discounted rate is sought as a result of a clear alignment between these outcomes and BrainsCAN's goals, and because it will unable us the opportunity to carry out more participants, which we will provide us with additional power, and additional control experiments, which will strength the overall validity of our experiments and help ensure that we continue to publish in flagship journals in our discipline (e.g. the investigators have published fMRI studies together in Nature Neuroscience (x1), Neuroimage (x4)).

2018


Biophysical Basis of the Resting State
PI: Menon, Ravi

Department: Robarts Research

Award Value: Reduced Scanning Rate

This project seeks to better understand how the biophysical basis of resting state fMRI (rs-fMRI). rs-fMRI is extensively used in studies in cognitive neuroscience, but the interpretation of increases and decreases in functional connectivity are poorly understood. To understand the circuit basis for cognition and the meaning of functional connectivity derived from rs-fMRI, we propose the following.

During the resting state, in which an individual is not performing any overt task, spontaneous neural activity throughout the brain reveals the brain's intrinsic functional architecture. Moreover, abnormal resting-state activity is found in many disease populations, presenting opportunity for using resting-state metrics as diagnostics and prognostics. The resting-state functional MRI (fMRI) signal is influenced by non-neural contributions such as motion and respiration, as well as other cellular contributions, such as astrocytes and glial signalling. Thus, at present, drawing conclusions from resting-state fMRI is highly tenuous. Directly measuring neural activity using sub-durally implanted, MR-compatible recording electrodes while simultaneously performing resting-state fMRI in animal populations provides an opportunity to better understand the extent of the neural contribution to the fMRI signal. Aspects of vascular tone or glial activity can be modulated independently of the neural activity to ascertain their contributions.

Mechanuisms of cortical depth dependent funtional MRI
PI: Shmuel, Amir

Department: Neurology and Neurosurgery, McGlll University

Award Value: Reduced Scanning Rate

The purpose of this project is to understand and model the mechanisms involved in functional MRI (fMRI) of cortical layers. High-field fMRI in human subjects has reached the technoligical level required to sample data from supragranular, granular and infragranular cortical layers. This advancement is a significant leap relative to what functional fMRI has achieved thus far, mainly measuring the activity at the resolution scale of cortical areas. Thanks to previous studies of anatomical connections in prmates, we know that intr-areal connections are systematically organized in specific cortical layers. Therefore, given its emerging capacity to measure cortical depth dependent activity, we expect that fMRI will soon be able to infer on casual interactions between cortical area. We expct that this advancement will revolutionize not only the study of the healthy brain, but also our capacity to utilize resting-state fMRI for early diagnosis and studying the pathophysiology of neurological diseases.

However, fMRI is not a direct measasure of neuronal activity; it infers changes in neuronal activity throught surrogate changes in metabolic and hemodynamic signals. Therefore, to correctly interpret layer dependent fMRI, models are required that tak into account the neurolal activity, the architecture of corticle vessels, changes in blood oxygenation and in cortical blood flow. Indeed our study aims to create such models.

This project aligns with the stratgic priorities of BrainsCAN. It involves collabortion of MRI experts (Dr. Menon and Mr. Gati) and a neurosience expert (Dr. Shmuel). It involves the using of imaging, invasive neurophysiology and computational modeling to understand and model mechanisms of fMRI at the resolution scale of cortical layers. This will make it possible to investigate the neuronal mechanisms underlying perception, action and fundamental aspects of how we learn, think, and communcicate. Moreover, it will contribute to understanding depth dependent resting state fMRI, which may increase its capacity to detect neurological diseases early on.

SeqRep4
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

This project addresses the question of how the human brain represents sequential movements before they are executed (i.e. during their planning), how these representations relate to those of executed movements, and how they develop at different stages of skill learning. Previous studies revealed that cortical motor areas represent skilled sequences more distinctly than novel sequences. However such studies have only focused on sequence representation during movement execution. Therefore it remains unclear how activity patterns change from sequence planning to sequence execution, or how planned representations develop over a training period.

Specifically, this project will address the following questions: 1) Are planned motor sequences represented similarly to executed motor sequences? 2) Are the brain regions involved during sequence planning the same as during sequence execution? 3) With training, do cortical motor regions move from a 'first finger' representation of the planned sequence to encoding the sequence as a whole? We aim to address these questions by examining the brain patterns associated with sequence planning and execution, and by using behavioral motor training. We will use high-field fMRI (7T) to obtain BOLD signal with higher specificity and signal-to-noise ratio than at conventional fMRI fields (e.g. 3T).

Neural Correlates of Speech Intelligibility
PI: Johnsrude, Ingrid

Department: Psychology, BMI

Award Value: Reduced Rate

We aim to investigate how patterns of brain activity underlie two cues that improve speech intelligibility in the presence of a competing talker: a) listening to a familiar voice compared to an unfamiliar voice, and b) spatially separating two simultaneous speech streams. Because both cues lead to increased intelligibility, we are interested in determining if each cue does so by activating the same neural networks. In this project, we will investigate the extent to which the improvement in intelligibility gained from these two cues is associated with activity in different brain regions. We will present participants with collocated or spatially separated sentences. Sentences will be spoken by either a familiar voice (i.e., participant's friend) or an unfamiliar voice (friend of another participant in the experiment). We will also collect behavioural measures of speech intelligibility during the scan (which our lab has already piloted extensively) to correlate with fMRI data, to assess which brain regions are sensitive to the magnitude of the behavioural speech intelligibility benefit for familiar voices and spatial separations across participants.

This research has potential implications for people with hearing loss, who often experience difficulty in understanding speech in noisy environments. Exploiting prior experience with voices might help these individuals to better understand speech in noisy settings which is prevalent in everyday life. By directly comparing neural correlates of cognitive (i.e., voice familiarity) and acoustic (spatial separation) cues, this project will improve understanding of whether declines in peripheral hearingmight be partially compensated for by cognitive cues.

PassivePatterns
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

Our lab is interested in understanding how the brain controls skillful hand movements. To study this with fMRI, to examine the measured patterns of activity while individuals perform finger movements, ranging from relatively simple single-finger movements to more complex sequences of multi-finger movements. With advanced statistical techniques developed in our lab, we compare differences between these activity patterns. The collection of these differences is referred to as the representational structure, which we use to provide insight into how the brain encodes certain features about the task or stimuli. Recent work from our lab using these analyses demonstrated a highly stable representational structure of finger movements across people, and demonstrated that it was well-characterized by the natural statistics of hand use.

Our ability to perform these skillful hand movements relies on sensory processing of tactile information perceived at the fingertips, given the observation that hand function is often impaired in patients with peripheral sensory damage. However, it is currently unknown how sensory-integration across fingers occurs in the cortex. This is an interesting question, given the observation that within the primary sensory cortex (S1), there is a clear gradient for finger representations (i.e. somatotopy). How does S1 successively build a representation of tactile features across fingers of the hand? In the current experiment, we will provide a systematic quantification of cortical neural representations elicited by passive single- and multi-finger stimulation in healthy individuals. We will calculate the representational structure for these movements in the cortex, and compare these representations along subregions within S1. Findings from this study will advance current understanding of the cortical contributions to finger sensory processing. Future work will evolve from this study that will target how attention and/or task-goals modulate this processing, and how this processing may be altered in individuals with peripheral nerve damage.

Human neural represetations of actions and bodies
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

Although the somatonsensory and moror systems have classically been thought to be organized based on maps of the body (somatoptopy), a recent proposal suggests they are organized into categories of actions essential for everyday function such as grasping, feeding and locomotion (Graziano, 2007, Neuron). Althought the notion that the behavioral repertoire is mapped onto the cortex is intriguing, the bulk of evidence has come from neurostimulation studies at high intensities and these studies have been intensely critiued as "neural hijacking" (e.g. Cheney et al., 2013, The Neuroscientist). This this theory desperately needs to be tested with other methodological approaches. More over, althought this organizational priciple has been suggestd across a variety of nonhuman primates (Kass et al., 2013 American Journal of Primatology), it would also be beneficial to test it in humans. A such, we will use functional MRI in humans to examine the relative contributions of action categories vs. somototopy.

During fMRI, we will presnt typical human participants with videos of ethological actions including grasping and reaching, feeding, locomotion, climbing and defensive movements. These videos will be shot to show whole bodies or body parts (particularly upper and lower limbs). We will use multivoxel representational similarity analysis to examine organizational principle(s) best account for spatial patterns of activation -- action based or body -part models. Key regions of interest will include motor cortex, somatosensory cortex, premotor cortex, specialized occipitotemporal regions involved in visual body recognition. Data-driven approaches may also suggest new principles. regardless of the outcome, the project should help resolve a heated debate and may open up new lines of research for future grants and projects.

The basic-research project is appropriate for BrainsCAN because it uses cutting edge approaches to investigate theoretically important orgnazation principles of sensorimotor system. A rich understanding of brain organization will provide a foundation for understanding brain function in health and in clinical disorders. The project will be a new collaboration between the Davare lab at the University of Leuven, Belgium and Jody Culham's lab and will provide fMRI training to a Belgium PhD student.

DCNmap
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

Our lab is interested in understanding the role of the cerebellum and brainstem in motor and non-motor function. To study these phenomena with fMRI, to examine the measured patterns of activity when individuals execute an extensive battery of tasks, ranging from finger movements to more complex tasks on different cognitive domains. With advanced statistical techniques developed in our lab, we have used the activity profiles in the cerebellum to create a functional parcellation. As a second step, we have proposed a new metric that allows to evaluate any functional parcellation by measuring the strength of each of its boundaries. Finally, we can evaluate the relationship between the activity profiles in the cerebellum compared to the cortex, this information is relevant to understand the cerebro-cerebellar interaction and communication.

However, the cerebro and cerebellar cortices do not have direct connections. The deep cerebellar nuclei and brainstem serve as relay points of communication. Therefore, a comprehensive model of the cerebro - cerebellar interaction cannot be completed without the proper analysis of the brainstem. Our goal with this project is to find and evaluate a functional mapping of the brainstem and then create a model of the interaction for the cerebellar - brainsteam - cortical loop. Findings from this study will advance current understanding of the cerebellar and brainstem contributions to cognitive function. Future work will evolve from this study targeting clinical populations, e.g. individuals who have suffered from stroke. Furthermore, functional imaging of the brainstem is challenging and will require several piloting, secuense testing and parameter tuning.

Bringing Virtual Reality into the Brain Scanner
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

We will develop virtual reality (VR) games for fMRI that may have many advantages over past approaches. VR games allow examination of a wide number of functions in a single paradigm under naturalistic conditions (and thus may prove superior to task-based fMRI). VR games are highly engaging and active (and thus may have benefits over other naturalistic but passive approaches like movie viewing). VR games should engage broad networks dynamically and actively (and thus may prove superior to resting-state approaches). To begin, we will focus on four domains that span a range of functions: visual perception, cognition (particularly navigation and memory), and sensorimotor control. If successful, the range of domains can be expanded in further studies.

In Stage 1, studies will examine the feasibility of using video games in fMRI. Participants will play commercial or customized video games in the scanner while their brain activation is measured. Event-related activity at key moments in the game (e.g., when making a decision during navigation or performing an action with an avatar) and can be used to examine (univariate) activation levels, (multivariate) activation patterns, intra-/inter-subject correlations, and functional connectivity. In Stage 2, the use of video games will be contrasted to conventional approaches. As one example, we will examine whether the control of actions by an avatar can yield more robust/useful activation than action imagery or action observation. In Stage 3, we will begin to combine successful approaches in earlier stages to create a single VR game that is optimized for testing multiple cognitive functions in a single paradigm.

HabitFormation
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

This project aims to examine habit formation and its neural representations after extended motor training. Practice leads to changes in varied aspects of behavior (e.g., skill vs. habit). Previous studies have shown the neural basis of behavioral changes with extensive training. However, a critical limitation is that it can be hard to measure habits precisely and separately from skill and thus it is unclear whether observed changes in neural activity relate to skills, habits, or both. In addition, existing imaging approaches relied on relatively simple analyses, seeking contrasts in overall brain activation across different task conditions or at different stages of practice. In this project, we will use our recently developed behavioral approach that reliably assesses habitual contribution to behavior and combine it with multivariate analysis techniques in imaging data. Our goal is to examine the neural representations of habits after a period of 2-week behavioral training. We will use high-field fMRI (7T) to obtain BOLD signal with higher specificity and signal-to-noise ratio than at conventional fMRI fields (e.g. 3T).

The combination of neuroimaging and behavioral assessments will allow us to better understand how habit forms after extended motor training. Understanding the habit formation and its neural representations is of considerable practical importance in physical therapy and rehabilitation, such as design an intervention to form new motor habits or break old habits that may no longer be appropriate.

Role of perirhinal and parietal cortex in making memory decisions
PI: Kohler, Stefan

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to explore how aspects of the medial temporal lobe, particularly perirhinal cortex (PrC), and the posterior parietal cortex (PPC) are involved in making different types of memory decisions. It is well documented that BOLD signals in both structures are implicated when people make memory decisions. However, how this activity relates to the outcome of such decisions remains poorly understood. Recently, several subregions within the PPC have been linked to making memory decisions. A question naturally following these discoveries is how these different regions interact with PrC to produce memory decision. Our project aims to address this issues with a novel behavioural paradigm that is capable of distinguishing decision-relevant versus decision-irrelevant memory signals for multiple memory judgments.

We will use fMRI methods to investigate processes involved in making memory decisions that go beyond the typical focus of most current research in the field, i.e., the medial temporal lobe. This will provide a better understanding of the link between various brain structures and behavioral measurements of memory. As PrC and PPC are both affected in Alzheimer's disease, this gain in basic knowledge can also lead to the development of new neural markers of these documented memory deficits.

Neural correlates of number symbols
PI: Ansari, Daniel

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to better understand how the human brain represents symbolic numbers (e.g., Arabic digits). We will compare brain activation of left-handed and right-handed participants as they passively view number symbols. fMRI adaptation will be used to identify brain regions that show adaptation to repeated presentation of a number digit, followed by rebound in activation with the presentation of a different number.

It investigates a fundamental aspect of human cognition: How the brain represents symbolic number. This previous work examined the neural response to the passive viewing of Arabic digits. The current study extends previous work by examining this symbolic number adaptation task in a group of left-handed and right-handed participants. A meta-analysis of existing fMRI studies of symbolic number processing demonstrated an association between activation of the left parietal lobe and symbolic number processing. However, the mechanisms underlying why the left parietal cortex appears to be more strongly associated with the processing of symbolic are unknown. A possible key mechanism may be handwriting and, by extension, the handedness of individuals. The few studies that have examined left as well as right handed individuals, report that handedness affects the neural laterality of various cognitive constructs. Additional research has shown that handedness of participants is an important factor with respect to hemispheric lateralization while processing symbols. Given the evidence for effects of handedness on laterality of various cognitive functions it can be predicted that handedness will affect laterality in other neurocognitive domains.

Neural mechanisms underlying autobiographical memory
PI: Owen, Adrian

Department: BMI

Award Value: Reduced Rate

This study aims to investigate the underlying neural mechanisms that support autobiographical memory. Human memory is typically tested in a laboratory setting using picture or word stimuli; while this often allows for tight experimental control over the learning experience, it this often does not capture the rich experience of personal episodic memories. In order to test episodic memories in a more naturalistic context, in this study we aim to capture and test autobiographical memories created when individuals navigate in their environment and engage in personally meaningful activities. Participants in this study will be shown two types of videos in the scanner: ones that were recorded by themselves, and videos that were recorded by other participants in the study. Each participant will be asked to indicate whether they recognize the videos presented to them as being (1) their own, or (2) not their own, as well as to rate their confidence level by pressing buttons on a response box. The aim of this procedure is to identify unique brain networks that contribute to experiencing personal memories (i.e. is there anything special about re-experiencing an autobiographical event vs. viewing a visually-similar event experienced by someone else?)

The objectives of this study are twofold. Its chief aim is to investigate autobiographical memory in neurologically normal participants. A secondary aim of this study is to establish an fMRI paradigm that could be used to test autobiographical memory in patients with disorders of consciousness (which will be done in a separate study). This study has implications to the overarching theme in our lab consciousness (being able to form personal memories implies having a sense of self / a higher degree of consciousness). It involves the use of imaging to evaluate brain networks underlying a basic function of the human experience; forming autobiographical memories. This experimental paradigm could then be extended to investigate the ability of patients with communicative disorders to form autobiographical memories.

Cognitive function in patients with disorders of consciousness
PI: Owen, Adrian

Department: BMI

Award Value: Reduced Rate

The differential diagnosis and prognosis of patients with disorders of consciousness heavily relies on the use of bedside behavioural measures of consciousness. The information obtained from these measures is limited and has been shown to be misrepresentative of some patients' true levels of consciousness. Approximately 20% of patients in the vegetative state have been found to be covertly aware - behaviourally indistinguishable from the vegetative state yet can modulate their neural responses in fMRI tasks similarly to healthy controls. The goal of this CIHR funded study is to further our understanding of residual cognition in this patient population and to develop neuroimaging paradigms to be used as diagnostic measures alongisde current clinical standards. This study will use classic motor imagery paradigms in addition to novel movie watching and auditory paradigms to parse out any residual neural modulation in these patients. We will also collect resting state fMRI and DTI to assess functional and structural connectivity to futher our understanding of the dichotomy between behavioural motor responses and motor imagery in covertly aware patients.

It involves the use of imaging to evaluate the nature and degree of cognitive impairment, including memory, attention and communication after severe traumatic brain injury.

2017


Human neural representations of food stimuli
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The prevalence of obesity is rapidly increasing, with the 20% of Canadians aged 18 and older classified as obese by the World Health Organization and Health Canada in 2014. Given the associated health risks with obesity such as cardiovascular diseases, hypertension and diabetes, numerous approaches have been proposed to investigate the alterations in the neural mechanisms of food-cue responsivity in this clinical population. Nonetheless, the mechanisms that lead to obesity are still poorly understood. Understanding which aspects of food cues drive food perception, categorization and reward-based responses in normal-weight individuals is thus of fundamental importance. Moreover, although studies of visual processing have demonstrated preferences and coding for many ecologically relevant object categories (e.g., faces, scenes, bodies), suprisingly little research has been done on the processing of food stimuli.

This study will use multivariate Representational Similarity Analysis of fMRI data collected on normal-weight individuals to provide an innovative, data-driven approach to understanding the factors that affect the neural representations of food stimuli related to behavioral variables (caloric content, level of processing, low-level features).

Functional connectivity for actions upon real objects and images
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this project is to understand how functional brain connectivity changes during hand actions toward real objects vs. images. Most human actions are performed upon real objects, yet psychology and neuroscience have typically studied two-dimensional images. Although real objects and images of the same objects share high visual similarity, they differ fundamentally in the actions that can be performed on them. Indeed, in a recent fMRI study we found dissociable multivariate representations for actions directed to real 3D objects compared to 2D images of the objects (Freud et al., in press, Cortex) in a key region along the dorsal visual pathway. Yet, recent advances also emphasize the role of distributed cortical networks in various complex cognitive functions.

The current study will employ a cutting-edge functional connectivity approach to examine how brain networks change as a function of stimulus type (real or image) and task (grasping, reaching, and passive viewing). We predict greater crosstalk between dorsal and ventral visual streams for tasks that require object processing (grasping vs. reaching and passive viewing), especially when the stimuli require pictorial processing (2D images).The project will provide a foundation for future studies examining how brain networks change in health and disorder. Moreover it is part of a larger project to understand which aspects of reality influence behavior and neural processing and may form a foundation for future studies to optimize virtual reality systems.

Validation of Movie-Driven fMRI and Memory Paradigm
PI: Johnsrude, Ingrid

Department: Psychology, BMI

Award Value: Reduced Rate

When participants watch an engaging film clip while undergoing fMRI, they tend to exhibit a stereotyped pattern of neuronal activation that is highly consistent across viewers. If a highly stereotyped pattern of activation is anticipated, then deviations from this neurotypical pattern (e.g., among individuals with neurological disorders) can be easily detected. This method may be particularly useful for patients with epilepsy who are candidates for resective surgery as a tool to probe for focal functional abnormalities in the brain (especially when no structural lesion has been identified). To assist interpretation of findings in a clinical sample, the psychometric properties of this method must first be evaluated in a neurologically healthy sample.

In addition to the neuroimaging data collected, we will administer a novel memory test and standardized neuropsychological measures. This multifaceted approach mirrors that of clinicians in the presurigcal work-up of patients with epilepsy, and involves the collaboration of basic scientists and clinicians. Additionally, the ultimate goal of this research is to devise an assessment tool that assists with localization of epileptogenic tissue for the purpose of presurgical planning in epilepsy. Specifically, using movie-driven fMRI and the companion memory test, we are well-poised to assess the functioning of medial temporal lobe structures such as the hippocampus in patients with temporal lobe epilepsy.

ExtFlexion
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

T Our lab is interested in understanding how the brain learns and produces skilled movements. To study these phenomena with fMRI, to examine the measured patterns of activity when individuals execute finger movements, ranging from relatively simple single-finger movements to more complex sequences of multi-finger movements. With advanced statistical techniques developed in our lab, we compare differences between these activity patterns. The collection of these differences is referred to as the representational structure. The representational structure of a region in the cortex provides insight into how the brain encodes certain features about the task or stimuli. Recent work from our lab using these analyses demonstrated a highly stable representational structure of single finger movements across people, and demonstrated that it was well-characterized by the natural statistics of hand use. However, it is currently unknown how components of finger movements (i.e. finger flexion and extension) are represented cortically. This is an interesting question, given the observation that flexion and extension finger movements are impaired differently following brain damage. Therefore, we believe that extension and flexion movements are generated through two separate motor control systems; one cortical and the other subcortical. While the differential loss in extension and flexion is a common clinical observation, the existing scientific evidence is conflicting.

In the current experiment, we will provide a systematic quantification of cortical neural representations associated with extension and flexion finger movements in healthy individuals. calculate the representational structure for these movements in the cortex. Findings from this study will advance current understanding of the cortical (and indirectly, subcortical) contributions to healthy hand function. Future work will evolve from this study targeting clinical populations who have impaired hand function (for example, individuals who have suffered from stroke).

LongSeqLearn
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

This project addresses the question of how motor sequence representations develop over the course of motor learning. Prior studies have shown that skilled cortical motor areas represent sequences more distinctly than novel sequences, and are associated with lower activation levels. However, it is has not been investigated how this pattern develops over the training period. Additionally, it is unclear what regions encode the various aspects of motor sequences during the different stages of motor learning. Specifically, this project will address the following questions: 1) Do motor sequences become represented more efficiently in cortical regions with learning? 2) Do representations shift from cortical to subcortical regions? 3) Do primary cortical regions develop a 'chunk' representation of finger presses rather than encode each of the sequential finger presses with extended training? 4) Do motor sequences become more or less generalisable across the two hands with training?

We aim to address these questions using extended behavioural motor training over a period of 1 month and examining brain patterns associated with sequence execution four times during this period. We will use high-field fMRI (7T) to obtain BOLD signal with higher specificity and signal-to-noise ratio than at conventional fMRI fields (e.g. 3T).The combination of neuroimaging and behavioural assessments will allow us to address the questions of how we learn skilled movements and provide a deeper understanding of what patterns of brain representations and structures are crucial during this process.

Role of the cerebellum in motor control and cognition
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

The primary aim of this study is to better understand functional mapping between the cerebral cortex and the cerebellum in response to cognitive task activation. While the emphasis in the literature has been on cerebellar activity during motor function, there are secondary theories of the cerebellum, which propose an important role for this brain region in non-motor function, namely cognitive and affective processing. Anatomical and functional evidence propose a topographic mapping between the cortex and cerebellum during tasks of cognitive function. We will be using functional magnetic resonance imaging (fMRI) and 27 different tasks to test motor and cognitive domain activation within-subjects in order to investigate functional mapping between the cortex and cerebellum. The current study is interested in knowing the rule(s) by which cerebellar activity becomes engaged by cortical activity.

It involves the use of imaging and a large cognitive battery to evaluate the functional mapping between the cerebral cortex and the cerebellum.

FiveDigitFreq
PI: Diedrichsen, Joern

Department: Statistical and Actuarial Sciences, Computer Science

Award Value: Reduced Scanning Rate

TOur lab is interested in understanding how the brain learns and produces skilled movements. To study these phenomena with fMRI, measured patterns of activity when individuals execute finger movements, ranging from relatively simple single-finger movements to more complex sequences of multi-finger movements. With advanced statistical techniques developed in our lab, we compare differences between these activity patterns. The collection of these differences is referred to as the representational structure.

The representational structure of a region in the cortex provides insight into how the brain encodes certain features about the task or stimuli. Recent work from our lab using these analyses demonstrated a highly stable representational structure of single finger movements across people, and demonstrated that it was well-characterized by the natural statistics of hand use. However, to make more advanced inferences with these representational structures, especially in the context of complex processes such as motor learning, we need to validate the stability of this technique in fMRI. Findings from this project will provide crucial insight when studying more complex activity patterns in the brain using these analyses in all neuroscientific domains.

Familiar Voices in the Brain
PI: Johnsrude, Ingrid

Department: Psychology, BMI

Award Value: Reduced Rate

This project aims to improve understanding of how patterns of brain activity underly the ability to understand familiar voices. We know that acoustic background noise can greatly reduce the ability to understand unfamiliar voices, whereas intelligibility of familiar voices is more robust to acoustic background noise. This intelligibility resiliance for familiar voices must have a neural underpinning. We predict that patterns of brain activity evoked by familiar voices will be more similar in clear and noise than patterns of brain activity evoked by unfamiliar vocies. We will test this hypothesis by collecting functional MRI data when participants hear sentences in quiet or in the presence of acoustic background noise. Sentences will be spoken by voices who are familiar to the participant (e.g. friends or partners) and voices who are unfamiliar (friends and partners of other participants). We will also collect behavioural measures of speech intelligibility (which have already been extensively tested in our lab) to correlate with fMRI data, to assess which brain regions are sensitive to the magnitude of the behavioural speech intelligibility benefit for familiar voices (compared to unfamiliar voices) across participants.

It investigates correlates of cognitive function in the brain. Specifically, the project explores how experience alters patterns of neural activity evoked by voices, and how those patterns relate to the ability to understand speech. The research has potential implications for people with hearing loss, who often struggle to understand speech in noisy listening environments: utilizing prior experience with voices might help these individuals to better understand speech in noisy acoustic settings, which was prevalent in everyday life.

Domain-specific and domain-general music and language processing using fMRI
PI: Johnsrude, Ingrid

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this collaborative project is to examine whether music and language are processed in shared or distinct regions in the typical adult brain. Previous work has provided evidence for largely distinct processing, yet a growing number of studies find evidence for overlap. Crucially, many of these studies fail to directly address inherent acoustic differences between language and music that are known to drive the recruitment of specific brain areas. The current project will use spoken and sung utterances to localize brain regions processing language and music. We will also present ambiguous utterances that can be perceived as both speech and song, while listeners provide subjective ratings about how whether each utterance sounds like speech or song. These ratings will allow us to examine the brain regions that are active when a participant perceives the same physical stimulus as either speech or song. In addition to standard univariate analyses, we will use representational similarity analysis to examine whether ambiguous excerpts perceived as song are more similar to overtly sung utterances and the same for speech.

The current project's goal is addressing cognitive function and communication in typically developing individuals toward a clincally relevant goal. A better understanding of the overlapping brain areas involved in processing music and language has the potential to significantly impact clinical populations, such as those recovering from stroke, or those with speech fluency deficits, such as stuttering. Specifically, identifying overlapping regions can help clinicians target interventions (e.g., highlighting rhythm or pitch relationships) to more effectively transfer fluency from the music to speech domain.

Neural patterns associated with streaming of ambiguous speech
PI: Johnsrude, Ingrid

Department: Psychology, BMI

Award Value: Reduced Rate

Relatively little is known about how the brain's auditory system supports the separation of sound mixtures into their underlying sources. This project applies multivariate analyses to the BOLD signal acquired with high-field fMRI while subjects listen to repeated sequences of syllables. These stimuli are bistable and can be perceived either as a single sound source or as two separate streams. The balance between these percepts is affected by acoustic properties of the signal as well as higher-level factors such as attention and linguistic knowledge. Comparing neural patterns when one vs. two streams are perceived, and under different acoustic and linguistic conditions, will allow us to link processes of perceptual organization to information representation at millimeter resolution.

First, to understand how brain disorders affect the interplay between cognitive and sensory processing, we need a solid grasp of how neural processing in the healthy brain supports the transformation of sensory information into perceptual representations. This study will form an important step in building such a basis, which is currently lacking for auditory perception in particular. Second, the study will play into and strengthen a new collaboration with partners at University of Iowa Hospitals Clinics. There we are collecting intracranial data from epilepsy patients using the same stimuli. The fMRI findings will inform connectivity analyses on those data, allowing us to apply a multi-modal approach to the research question.

Mitigating Mass-Distribution Artefacts in fMRI
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this project is to mitigate image artefacts caused by subject or apparatus motion outside the imaging field of view. BrainsCAN seeks to understand fundamental aspects of how we move. Our research investigates actions (such as reaching, grasping, and tool use) and real-world objects and thus requires motion of either the participant's limbs or experimental apparatus to present real objects in the scanner. The Culham Lab has two decades of experience pushing the technical limits to enable experiments once thought impossible. Indeed, our innovative approaches on body actions and real-world scenarios have formed the foundation of a strong history of CIHR and NSERC funding, resepectively. However, until we test and implement new approaches to addressing artefacts from bodily and equipment motion, the extent to which we can push the limits in the future is constrained. A reliable and successful correction of these artefacts is needed: (1) To ensure that data from these fMRI studies are not corrupted by false positive activation. (2) To obtain better quality data and thus increase statistical power: The artefacts can conceal true BOLD activation, decreasing intensity of the activation of interest and thus decreasing statistical power. (3) To allow the lab to spend far less time troubleshooting new paradigms that involve moving body parts or apparatus. (4) To enable the study of a wider range of bodily movements, postures and equipment to be studied using fMRI

Validating a reliable correction method would have broader implication for labs studying actions in real-world environments in our lab, in other labs at Western, and in the cognitive neuroscience community more generally. These solutions would be particularly valuable for extending the range of motor control tasks that could be applied to understand the neural basis of movement disorders. The current project will investigate several avenues, including the utility of independent component analysis (ICA) strategies to mitigate fMRI mass-motion artifacts resulting from arm movements in the scanner and perhaps multi-echo approaches. One publicly available ICA approach, Automated Removal of Motion Artefacts (ICA-AROMA), has not yet been used to correct for mass distribution artefacts. If ICA-AROMA is confirmed to be successful at correcting artefacts arising from motion outside the field of view, it could open up new avenues of exploration action and grasping research using fMRI.

Neurological mechanisms underlying the understanding of social action
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this project is to investigate how action planning and execution is influenced by social intentions. Effective social interaction is predicated upon accurate prediction. To act within a social environment requires that individuals be able to use their own behaviour to signal their intentions and form predictions concerning how others will respond to their actions. Though we are constantly acting with other people in our everyday lives, the field's current understanding of the neural underpinnings of social actions is sparse. Moreover, of the relatively few social action studies that have been performed thus far, the majority make use of images, videos, or auditory stimuli instead of investigating real-time social actions between a participant and a physically-present partner. There is growing consensus in the social cognitive neuroscience field that research must emphasize ecologically valid approaches (e.g. studing responses to real, vs. videotaped interaction) in order to better understand social cognitive functioning.

The current study will scan participants who will interact in real-time with another person who will be physically present in the room. Using traditional and advanced analysis techniques such as multivoxel pattern analysis (MVPA), we will compare neural activity and neural patterns within motor and social brain networks when a) participants perform social or non-social actions, and b) when they observe those actions being performed by a partner outside of the scanner. We anticipate that through MVPA analysis, we will be able to decode social v. nonsocial action intentions within social and motor networks. This project constitutes an important initial step to understanding social action and nonverbal communication, which can later be extended to explore how activity and network involvement changes in various disorders, such as Autism Spectrum Disorder, Schizophrenia, and Parkinson's disease.

Functional connectivity for actions upon real objects and images
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this research project is to explore the neural signature of visual perception of size and distance of real-world objects. On the one hand, we seek to find out neural responses to naturally-occurring real-world objects in both ventral and dorsal visual stream areas. For example, we will find out whether object-selective areas, such as the lateral-occipital complex (LOC) and the lateral intraparietal area (LIP) are, respectively, sensitive to small differences in the familiar size and physical size of otherwise very similar cubic hand-held objects (i.e., a naturally small die vs a naturally large Rubik's cube). Additionally, we will measure responses to these objects at different viewing distances to record a neural signature of size constancy, which is a mechanism that lets us perceive a certain object as the same regardless of its decreasing retinal angle with an increasing viewing distance (Emmert's law).

On the other hand, we also plan to explore how the brain responses to the violations of the well-learned visual contingencies. We have created a playing die and a Rubik's cube in reverse physical sizes to see how the ventral and the dorsal stream areas will respond to the unusual familiar and physical sizes of objects, respectively. These incongruently-sized objects will also be viewed at various distances, so that we can compare how the brain responds to the violations of size constancy, when, contrary to the expected decrease of the visual angle, a die, for example, will be viewed at a farther distance but at the same retinal angle (because a large die will be presented instead).

Pattern separation in object perception
PI: Kohler, Stefan

Department: Psychology

Award Value: Reduced Rate

The goal of the current project is to explore whether the process of pattern separation occurs outside of the hippocampus, and whether or not we can use novel multivariate fMRI methods to characterize this process. Pattern separation has been defined as the process of taking highly similar inputs and making them more dissimilar in order to reduce interference amongst stored representations. Previous research has focused on pattern separation as a hippocampal function crucial for retrieving distinct long term memories (i.e., where you parked your car a certain day in the same parking lot you park in everyday). Recently, it has been suggested that pattern separation may be a more general neural function, and may subserve crucial cognitive abilities outside of episodic memory. Our project aims to test this by seeing whether pattern separation occurs in high level visual cortex for object perception. Specifically, we aim to evaluate changes in patterns of activity across voxels evoked by visual objects of varying perceptual similarity.

We will use fMRI methods to characterize a basic neural function (pattern separation) that has largely been investigated in non-human animal studies, and to understand how this function contributes to perception and memory. This gain in basic understanding may aid in better understanding pathology in these regions. Changes in hippocampal-mediated pattern separation abilities have been linked to the development of dementia, but changes in pattern separation outside of the hippocampus in areas that are actually first affected in AD (perirhinal and entorhinal cortex) have not been explored, but could potentially provide more sensitive diagnostic markers.

fMRI data for Psychology 9223 and online tutorials
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

BrainsCAN has approved funding to collect data that will be used for teaching purposes, including my graduate course, Psychology 9223: Neuroimaging of Cognition, and an online fMRI teaching platform to be developed, perhaps as part of my website, www.fMRI4newbies.com, or perhaps as an independent BrainsCAN/BMI teaching (to be determined in consultation with other members like Joern Diedrichsen and Ali Khan).

The plan includes a core data set (n=15) at 3T using a rapid event-related experiment to examine questions about category selectivity in cortical visual areas using either a region-of-interest or whole-brain voxelwise approach. In addition, single participants will be tested on variants of the core design for didactic purposes (e.g., suboptimal event-related designs, optimal and suboptimal block designs, contamination with various types of artifacts like swallowing, deep breathing and head motion; high-resolution at 7T, etc.).

Neural correlates of manual interception of moving objects
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

The purpose of this experiment is to investigate the neural correlates of manual interception of dynamic objects. Our world is inherently dynamic. However, the large majority of the research on the neural correlates of reaching involve reaching or interacting with static objects, while research the neural correlates of reaching to dynamic objects remains sparse. To successfully intercept a dynamic object, object motion must be recognised, object trajectory must be extrapolated, and a successful motor action must be executed. While motion perception, attentive tracking of moving objects, and manual reaching to static objects has been extensively studied in the context of functional magnetic resonance imaging, they have not been combined in a single task to study reaching to dynamic objects.

The current study will scan participants performing a reach-to-point task on a MRI-compatible touch screen. Using traditional analysis techniques, we will compare neural activity within visual sensory and motor brain networks involved in the temporal and spatial component of reaching when a) participants intercept a moving virtual object, b) when participants anticipate the timing of a moving object.

Representational similarity analysis (RSA) of object form, material and grasp points
PI: Culham, Jody

Department: Psychology, BMI

Award Value: Reduced Rate

In this project we aim to study brain areas involved in visually guided grasp planning. We will scan participants performing a precision grip grasp task with a range of objects varying in both shape and material properties. The objects will be selected through a theory-driven approach to maximally discriminate the brain areas involved in the different computations underlying grasp planning. We will compare neural activity within visual sensory and motor brain networks involved in both temporal and spatial components of grasping.

In the long run we plan to translate this research into medical applications. We plan to employ our findings to predict how stroke patients might be affected by different lesions and to develop theory-driven treatment strategies. We will benefit from the reduced rates, as this study is a crucial 1st step towards solving this problem.

Retinotopy in hippocampus (hc-ret)
PI: Kohler, Stefan

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to provide a detailed investigation of visual responses in human hippocampus. Previous work suggests that hippocampus may play some functional role in visual perception. However, the specific properties of responses to visual stimuli in human hippocampus are not well understood. In particular, it is currently unknown whether responses in human hippocampus are biased toward stimuli presented in the periphery of the visual field, as has been observed in parahippocampal cortex, which projects to at least some hippocampal subfields. In the current study, we will use high resolution MRI and population receptive field modeling techniques to characterize several tuning functions (e.g., size, eccentricity) for each voxel in hippocampus and parahippocampal cortex. The results are expected to provide new insights into the role of human hippocampus in visual perception.

This information may aid in better understanding the consequences of damage to human hippocampus. Previous studies have reported differences in visual perception associated with damage to hippocampus. By providing new insights into the organization of visual responses in hippocampus, our work could refine the understanding of the relationship between the characteristics of hippocampal damage (e.g., which subfields are damaged) and changes in visual perception and memory in clinical neurological popluations in which hippocampal abnormalities have been implicated, such as Alzheimer's disease, epilepsy, and stroke.

Number Symbols in the Brain and Mind
PI: Ansari, Daniel

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to better understand how our brains come to process numerical symbols (i.e. words and Arabic digits), over the course of learning and development. Specifically, we aim to investigate the existence of a Number Form Area (NFA) that underpins the visual representation of Arabic digits.

It is investigating a fundamental aspect of human cognition: How do we learn to recognize and attribute numerical meaning to number symbols? The current project is a replication and extension of previous work identifying the NFA, a region in ventral visual cortex that responds preferentially to number symbols compared to other categories, including letters and false fonts. Once we confirm that we can image this region in adults, we aim to conduct a developmental study of this region. This region is adjacent to the visual word form area (VWFA), a region that responds preferentially to letters over other categories, and that is associated with reading performance and reading difficulties. We aim to explore whether individual differences in neural responses in the NFA may similarly be related to mathematics performance and whether abherrant neural responses in this region could be a marker of mathematics learning difficulty.

Enumeration Adaptation
PI: Ansari, Daniel

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to better understand how the human brain processes different dimensions of arrays of symbolic numbers. Specifically, we aim to investigate how different parts of the brain respond to symbolic number symbols (i.e. arabic digits), nonsymbolic numbers (i.e. quantity), and physical size of numbers. We plan to use fMRI adaptation methodology to make regions of the brain adapt to many aspects of an array of numbers to examine the neural rebound of individual dimensions of the arrays.

It is investigating a fundamental aspect of human cognition: How the human brain represents numbers. The results revealed a ratio-dependent neural rebound effect in the left (IPS) in response to Arabic digits. In this previous research, the stimuli are intended to lead to adaptation to only Arabic numerals. The current study seeks to extend this paradigm by adapting brain regions to several dimensions of number including that numbers are symbols, the actual symbolic number (i.e. '6'), how many numbers are presented (i.e. four), and the size of those numbers. To do this, participants will be adapted to an array of four 6's of a certain size, rather than a single digit. To the best of our knowledge, this will be the first study with a paradigm that leads to adaptation of multiple dimensions of a construct. This novel adaptation paradigm will allow us to examine neural responses to a change a single dimension of the array of digits.

Investigating the neural mechanisms underlying learning
PI: Owen, Adrian

Department: BMI

Award Value: Reduced Rate

This study aims to examine the underlying changes to the brain caused by extended training on higher-level cognitive tasks. The brain networks most affected training related improvements that target specific cognitive systems, and the neural mechanisms that allow for transferable gains to untrained tasks, for some, but not most, remains unknown. This longitudinal fMRI study will investigate (1) the underlying neural systems (structural and functional) that characterize different aspects of higher cognitive function, (2) the degree of plasticity in these systems as a result of prolonged training, (3) how intensive training changes the underlying neural network of the trained task, and how that relates to performance on untrained tasks, and 4) whether changes to different brain networks are linked to individual's learning ability, which may serve as a tool for identifying learning disabilities. To this end, healthy young adults will complete a series of training sessions with cognitive tasks from a validated cognitive assessment tool. Each participant will complete 10 hours of training with these tasks across 20 days within a 30-day period. At the end of the training sessions, participants will be tested on the same two tasks they trained on, plus two additional tasks: one that tests near transfer, and another that tests far transfer.

fMRI and DTI scanning will be done before, after, and 3 additional times during the training sessions (following every 2.5 hours of practice). This will allow to (1) establish the neural characteristics of each task before training, (2) to investigate how training affects the degree of plasticity within each of these networks, and (3) track the neural plasticity that is established with training. Scanning will be done as participants perform the tasks, as well as during a short period of rest following each scanning session.

Learning to read in a foreign context
PI: Rafat, Yasaman

Department: language and literature

Award Value: Reduced Rate

The purpose of this project is to understand the differential involvement of different brain networks in reading in different contexts in bilinguals. We will conduct an rTMS study to determine the degree of involvement of the ventral and the dorsal pathways in reading in both English and Spanish in English-Spanish and Spanish-English bilinguals. We anticipate collecting data over the next six to twelve monthes. Given individual differences, we will need to perform MRI once on each participant over this period.

It involves the use of imaging and cognitive batteries to evaluate the neural bases of bilingualism and how this influences literacy and second language learning outcomes in adults. It involves collaboration of basic-scientists to achieve this goal.

Role of Basal Ganglia in Beat Perception
PI: Grahn, Jessica

Department: BMI

Award Value: Reduced Rate

The goal of this project is to assess the role of the basal ganglia in beat-based rhythm perception, specifically whether the basal ganglia response is driven by predictability or by the 'relative' timing (as opposed to 'absolute' timing) afforded by beat-based rhythms. We will use standard imaging techniques to examine activation in this region during learned (predictable) and novel rhythms. Learned and novel sets of stimuli will both include beat-based and non-beat-based rhythms. This design allows the comparison of basal ganglia activity between predictable and unpredictable rhythms, as well as differences in beat-based (relative timing) and non-beat-based (absolute timing) rhythm perception. Results from this study will clarify the role of basal ganglia functioning during beat perception. Additional multivariate analyses will look at representational structure of rhythms in cortical areas.

This project goal is to increase understanding of disorders of the brain. Deficits in beat perception have previously been found in clinical populations, such as Parkinson's disease patients. Therefore, understanding the role of the basal ganglia will be beneficial in understanding mechanisms driving these disorders. By revealing the functional aspects of the basal ganglia, results of this study can also inform clinical therapeutic interventions that target disorders of this brain area.

Comparing Beat Perception in Humans and Non-Human Primates
PI: Grahn, Jessica

Department: BMI

Award Value: Reduced Rate

Despite the amazing level of shared neural machinery between humans and nonhuman primates, only humans appear to sense and react to musical rhythm. This ability has played a major role in human culture for millennia. We aim to understand the neural processes that underpin our uniquely human ability to sense the beat in rhythmic sequences, by comparing brain responses across species with the most advanced magnetic resonance imaging (MRI) methods available.

Theoretical timing models are based on nonhuman animal data, but fail to consider differences between animal and human timing behaviour. Understanding the neurobiological foundations of beat and rhythm will inform models of brain function and neural mechanisms of timing, and also shed light on our universal and unique sensitivity to music. In addition, the rare nature of these datasets will provide rich opportunities for exploratory comparisons with multi-disciplinary applications.

NHP_RepStructure
PI: Pruszynski, Andrew

Department: Robarts Research

Award Value: Reduced Rate

Our lab is interested in understanding how the brain learns and produces skilled movements. To study these phenomena with fMRI, we take advantage of the advanced imaging facilities at Robarts UWO to examine the measured patterns of activity when individuals execute finger movements, ranging from relatively simple single-finger movements to more complex sequences of multi-finger movements. With advanced statistical techniques developed in our lab, we compare differences between these activity patterns. The collection of these differences is referred to as the representational structure. The representational structure of a region in the cortex provides insight into how the brain encodes certain features about the task or stimuli. Recent work from our lab using these analyses demonstrated a highly stable representational structure of single finger movements across people, and demonstrated that it was well-characterized by the natural statistics of hand use.

However, fMRI is a non-linear proxy of real neural activity. Therefore, in order to make inferences about neural activity that underlies how the brain encodes certain task/stimuli features using these analyses, we must investigate the relationship between representational structures estimated for the same features across different measurement modalities. In this project, we will compare the representational structure for fingers using data from fMRI and array recordings in non-human primates (NHPs).

Representation of haptic size in sighted and blind individuals
PI: Goodale, Mel

Department: BMI

Award Value: Reduced Rate

The purpose of this project is to understand how sighted and blind individuals represent haptic size. Size is a basic feature of objects which not only influences one's visual experience of an object but also determines the nature of the actions one might perform upon it. There are many studies on the representation of visual size in the brain, principally in visual cortex, but far fewer studies that have examined the representation of haptic size, even though haptic size provides important sensory feedback during actions such as grasping. The first question we are interested in is whether or not the areas that represent visual size and haptic size overlap or are completely separate. The second question is whether or not the representation of haptic size is different in sighted and blind individuals. Previous studies have shown that the visual cortex of blind individuals is recruited in the processing of tactile information. Therefore, we predict that the visual cortex of blind individuals, but not sighted individuals, may be involved in haptic size perception. In addition, to explore the role of early visual experience in the representation of haptic size in blind individuals, we will also compare the representation of haptic size in congenital blind and late blind groups.

It involves the use of imaging and behavioral evaluation to study the deficits and neuroplasticity in blind individuals. Bindness is a major health problem in Canada; more than 5.5 million Canadians have a major eye disease that could cause vision loss. According to a recent study, the prevalence of low vision and blindness is around 36 and 4 per 10,000 individuals respectively in North America.

Principles underlying representation of animate and inanimate objects in the ventral stream
PI: Goodale, Mel

Department: BMI

Award Value: Reduced Rate

Evidence from neuropsychology suggests that conceptual knowledge in the brain is not organized randomly, but sometimes follows categorical boundaries, as demonstrated by the category-specific semantic deficits in patients with agnosia. For example, the knowledge about animate objects can be selectively impaired while the knowledge about inanimate objects is unaffected, and vice versa, suggesting that object animacy is an important organizing principle for conceptual representations. Understanding the nature of these representations is crucial for understanding such deficits. Multiple studies on ventral visual stream organization have reported distinct representations of animate and inanimate objects in ventral temporal cortex (VTC). However, since this region is involved in processing both object category and object form, it was unclear whether this distinction is driven by category or visual features. Recent studies have addressed this question by using images of animate and inanimate objects that were carefully matched for shape features (e.g., snake-rope), and found that information about object animacy is still present in VTC even after controlling for overall shape. However, these studies did not control for other prominent features of animate objects, (such as head and face) that often distinguish them from inanimate objects.

The aim of this study is to understand whether or not animate/inanimate distinction in VTC could be explained by selectivity to head and face features. Participants will view images of animals with or without faces (e.g. snake-worm), as well as inanimate objects. We will use representational similarity analysis to see if animals without characteristic head and face features are still distinct from the representations of inanimate stimuli. The results will provide further insights into the functional organization of the ventral visual stream, contributing to the ongoing debate about the nature of category-specific object representations. It could improve our understanding of the neural correlates of semantic deficits in agnosia patients -- and provide new directions for cognitive rehabilitation.

MagnetoVestibular Stimulation
PI: Corneil, Brian

Department: PhysPharm

Award Value: Reduced Rate

Several phenomena regarding the interaction of the static magnetic field and subjective complaints of dizziness have been well documented and may well have implications to high-field fMRI. The strong static magnetic field used for MRI produces magnetovestibular stimulation (MVS) within the inner ear, via Lorentz forces that chronically displace the cupula within the semicircular canals. MVS magnitude is proportional to the static field strength (hence larger at 7T than 3T), absent in patients lacking vestibular function, and related to the idiosyncratic anatomy of the inner ear. Due to MVS, subjects situated in high-field magnets exhibit nystagmus when in the dark, with alternating patterns of slow-phase and quick-phase eye movements. If subjects are placed in the light, the oculomotor system actively stabilizes the visual world by preventing nystagmus, although MVS is still present. We plan to i) explore the effects of MVS on behaviour, and ii) investigate the influence of MVS on signalling within the fronto-parietal resting-state network. In meeting these objectives, we will advance the understanding of the behavioural and signalling implications of high-field MVS. Both of these objectives will be studied at 7T.

This research proposal meshes with the strategic positioning of BrainsCAN. fMRI will remain an essential tool within cognitive neuroscience, but MVS has only recently been recognized and numerous implications remain to be explored. The presence of MVS does not invalidate the results that can be gained via high-field imaging. Instead, the influences of MVS at high-fields have to be detailed, and if necessary, controlled for through head positioning. MVS also provides a potentially unique tool for investigating vestibular function in healthy and patient populations. We are also exploring the feasibilty of combining eye movement measures with ongoing studies in patient populations (e.g., Parkinsons).

Visually-evoked activity
PI: Butler, Blake

Department: Psychology

Award Value: Reduced Rate

The purpose of this project is to determine the anaesthetic and data collection protocols necessary to optimize the imaging of visually-evoked neural activity in the cat. When one sensory modality is lost, such as in deafness, the area of cortex that would normally process stimuli in the abset modality is functionally reorganized to contribute to the remaining senses. While this is often considered to be compensatory in nature, we hypothesize that this rededication of cortical resources may contribute to the inability of some cochlear implant users to acquire language skills similar to their normal hearing peers.

This study seeks to optimize imaging of visually-evoked activity in visual and auditory cortices of hearing and deaf animals. Our current flexible feline coil will be modified to allow a better line of sight, and custom hardware will be sought to allow for the presentation of high-resolution visual stimuli to an animal facing the rear of the 7T scanner. This will allow us to pursue an exiciting line of research designed to observe the onset of visual function in presumptive auditory cortical regions, and the degree to which these areas can be rededicated to auditory perception following the resumption of hearing via a cochlear prosthesis. Moreover, we hope that the anaesthetic profile determined to be optimal in the cat may inform similar protocols across other animal models in use at Western University.