Current Research Projects
Predicting treatment response in military PTSD
This naturalistic longitudinal study investigates changes in brain activity that track symptom improvement in individuals with military PTSD. Current and former Canadian Armed Forces members with PTSD undergo an fMRI scan while performing a cognitive task with emotionally-salient distractors. MRI scans and other clinical and biological measures are collected before and after treatment and used to predict clinical outcomes.
Mechanisms of pleasure and motivation deficits in schizophrenia
This study uses a novel behavioural task to search for patterns of brain activity that track subjective pleasure and predict willingness to pay or willingness to work for rewards. In this task, participants watch movie trailers during fMRI scanning and bid money or exert effort to win a personal copy of the movies advertised. We will see if these activity patterns representing pleasure or value are disrupted in individuals with schizophrenia suffering from negative symptoms and whether this disruption occurs during the experience of pleasure and/or during the subsequent process of decision making.
Neuromelanin-sensitive imaging of the substantia nigra and locus coeruleus
The neurotransmitters dopamine and noradrenalin are released from neurons located in the substantia nigra and locus coeruleus respectively. These structures have the unique property of containing high concentrations of neuromelanin, a dark pigment that can be visualized with specialized MRI sequences. The neuromelanin-sensitive MRI signal has been used to visualize degeneration of these neurons in Parkinson’s disease and healthy aging. Our recent work has shown that this signal can also serve as a proxy measure for long-term imbalance in activity of these neurotransmitter systems. Current projects are investigating this novel measure as a potential biomarker in diverse populations including, schizophrenia, individuals at-risk of schizophrenia, Parkinson’s disease, addiction, PTSD, and healthy aging. Other work uses dopamine PET imaging and post-mortem midbrain tissue to better validate this technique and interpret the neuromelanin MRI signal.