Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Schizophrenia is a disabling disease affecting 1 in 100 Canadians. Sufferers may have hallucinations, implausible beliefs, and poor social skills. Cognitive deficits in attention, learning, and memory are common and limit patients' ability to work, socialize and lead productive lives. However, there is a subset of patients (25-35%) without these deficits yet have the same severity of psychotic symptoms. These individuals with schizophrenia provide a unique opportunity to tease apart brain abnormalities that may lead to psychosis with or without cognitive deficits. Evidence suggests that certain brain areas are active at rest when individuals are focusing on their inner thoughts and feelings (e.g., daydreaming). Interestingly, this network of brain areas, termed the Default Network, is deactivated when attention is focused on the outside world, and brain regions needed for external focus become activated. An over-active Default Network may lead to psychosis in schizophrenia. When over-active, this network does not deactivate, but rather suppresses other brain areas required to process and focus on external information, contributing to cognitive deficits. Thus, the psychotic symptoms and cognitive deficits in schizophrenia may be the result of an over-active Default Network. I will examine schizophrenia patients with and without cognitive deficits and healthy controls to assess differences in brain structure, cognition, and functional outcome. I will use imaging techniques to identify patients' shared and unshared brain abnormalities in this network and other brain regions. Studying cognitively normal and below average patients may help to differentiate brain processes tied specifically to psychotic illness from those related to cognitive deficits. Identifying psychosis-specific processes within the schizophrenic brain and their link to overall functioning may greatly advance understanding of the disease and therapeutic options available to people with the disorder.