CURRENT RESEARCH



Non-invasive imaging of sensorimotor plasticity following cranial nerve repair

Co-investigators:
Gregory Borschel MD, The Hospital for Sick Children
Tom Chau PhD, Holland Bloorview
Elizabeth Donner MD, The Hospital for Sick Children
Pascal van Lieshout PhD, Department of Speech-Lanugage Pathology, Univerisity of Toronto

Industrial Partner:
CTF MEG International Services LP, Coquitlam, BC

Funded by:
Canadian Institutes of Health Research (CIHR)

The human brain undergoes constant changes as we learn new skills or recover from potentially life-altering injuries, such as limb loss or disease. This well-known ability to “rewire” neural connections that are established at birth — a phenomena known as neuroplasticity — has been extensively demonstrated in animal models which show both structural and functional changes at multiple levels of the nervous system. However, human studies are often limited to only post-injury observations of highly variable injuries and recoveries. Furthermore, human neuroimaging studies involving nerve injuries are virtually non-existent. Our study will be the first to non-invasively measure neuroplasticity in the human brain before and following surgical repair of cranial nerves using the simultaneous measurement of detailed facial motor control (kinematics) and brain activity. These novel measurements will be made possible by the development of an advanced MEG compatible real-time motion tracking system as part of a Canadian Institutes of Health Research (CIHR) funded collaboration between our lab at the Hospital for Sick Children, the PRISM lab at Holland-Bloorview Kids Rehabilitation Hospital and our Canadian MEG manufacturer CTF-MISLP located in Coquitlam, BC, Canada. This will allow us to monitor changes that occur over time in sensory and motor systems in children undergoing facial motor repair before and after their surgery, and to study the influence of age at the time of injury (congenital or acquired) as well as the length of time between surgery to full recovery. Our goal is to establish which factors influence the speed or success of recovery in these clinical populations. The resulting technology will have broad future application in other clinical disorders affecting the cranial nerves, such as Bell’s Palsy, dysphagia, motor neuron disease, and others for which there is currently no non-invasive technology available to assess recovery at the behavioural or brain level.


Imaging brain activity in children with stroke

Co-investigators:
Gabriel deVeber MD, Division of Neurology, The Hospital for Sick Children
Nomazulu Dlamini MD, Division of Neurology, The Hospital for Sick Children
Andrea Kassner PhD, Department of Medical Imaging, The Hospital for Sick Children

Funded by:
Canadian Institutes of Health Research (CIHR)

Currently there is very little understanding of why some stroke patients develop dystonic symptoms, usually appearing several months following their stroke, and why this is more prevalent in children. This 3-year CIHR funded project will focus on the use of MEG and MRI imaging in children recovering from stroke who develop hemidystonia or other motor disorders. Our hope is that neuroimaging during targeted motor tasks will help understand the neural mechanisms underlying the development of hypertonia in these patients, and possibly provide predictors of outcome.


Automatic and controlled processes in inhibitory control

Funded by:
Natural Sciences and Engineering Research Council (NSERC)

Funded by a 5-year NSERC Discovery grant, IMS graduate student Silvia Isabella is conducting MEG studies on the role of automatic and controlled cognitive processing response inhibition and error monitoring during continuous performance tasks. We are using a novel combination of eye-movement and pupil diameter tracking and MEG recordings to obtain covert measures of mind-wandering or "off-task" mental states and how they influence the way in which we inhibit prepotent responses or process motor errors. This research will enhance our understanding of the neural basis of cognitive control and may have utility in both human factors applications and in the study of attentional deficits in brain injured patients or other disorders.


Modeling epileptic brain activity with MEG

Co-investigators:
Hiroshi Otsubo MD, The Hospital for Sick Children
Jason Lerch PhD, The Hospital for Sick Children
Elysa Widjaja MD, The Hospital for Sick Children
Richard Wennberg MD, PhD, Toronto Western Hospital

Funded by:
Ontario Brain Institute (EpLink)

This project involves development of novel source localization techniques for the identification of the generators of epileptic brain activity. We are using both numerical simulations and a visual retinotopy model to test the ability to use MEG and advanced mathematical algorithms to map large areas of activation in the brain during interictal epileptiform discharges. The long-term goal is to validate these methods using MEG and electrocorticogram (ECoG) recordings in patients undergoing surgical treatment for epilepsy.


Constraint therapy in hemiplegic cerebral palsy

Co-investigators:
Darcy Fehlings MD, Holland-Bloorview Kids Rehabilitation Hospital

Funded by:
Ontario Brain Institute (CPNet)

Together with scientists and clinicians at Holland-Bloorview Kids Rehabilitation Hospital we are conducting neuroimaging studies in children with hemiplegic cerebral palsy who are undergoing a therapeutic intervention known as "constraint-induced movement therapy (CIMT)" to alleviate symptoms related to developmental disregard (learned disuse) of their upper limbs. We are currently carrying out an MEG study on a cohort of children undergoing constraint therapy to determine if changes in sensory and motor areas of the brain correlate with outcome.


EXTERNAL FUNDING


Our research is supported by grants from Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI) and the Ontario Brain Institute (OBI).