Auditory Entrainment and Symptoms Across Diagnoses
Auditory entrainment is based on the idea that physiological functions such as brainwaves tend to synchronize to rapid auditory stimuli and thus provide a basic test of integrity of neural network and sensory pathways. Auditory entrainment has been found to be impaired in schizophrenia and may be associated with alterations in long-range synchrony that are required for integrative cognitive functioning. We are currently looking at whether the steady state auditory entrainment deficit is unique to schizophrenia by comparing them to bipolar disorder and healthy control.
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Theory of Mind in Schizophrenia
Theory of Mind (ToM) – or the ability to infer one’s own and other persons’ mental states such as beliefs, desires, intentions and emotions – is an important skill to possess in order to successfully navigate through our rich social world. As evidence accumulates to support the hypothesis that ToM is impaired in people with schizophrenia, the focus of research has shifted toward understanding the neural basis of cognitive function and identifying the brain regions specific to this ability. We will be investigating the electrophysiological marker for ToM reasoning in people with schizophrenia and whether mental representation is amenable to training.
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Attention and Auditory Sensory Gating in Schizophrenia
This study investigates the role that attention has in the brain’s ability to filter basic auditory sensory information. The central nervous system’s ability to filter such information is also referred to as auditory “sensory gating”. Auditory sensory gating is commonly measured with EEG by analyzing the suppression of the P50 waveform after the presentation of repetitive stimuli. Those with schizophrenia have been shown to have deficient P50 suppression when compared to healthy controls. The brain’s suppression of the P50 has long been though of as a “bottom-up” process beyond conscious control, however, recent findings have suggested that having schizophrenic individuals selectively attend to the stimuli may in fact amend this deficiency. This study will investigate the underlying mechanisms of the attentional modulation of P50 suppression by looking at the specific frequency bands that contribute to this waveform. Understanding this mechanism will help determine whether this sensory processing deficit in schizophrenia is a possible target for cognitive remediation.
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Binge Study
The relatively high prevalence of binge eating and drinking in young women combined with the potential for negative consequences including the development of severe alcohol and eating pathology highlight the importance of understanding risk factors for these behaviour patterns. These behaviours have been consistently linked to negative mood states with alcohol use also associated with positive affect. Further, studies employing self-report measures have suggested emotion regulation deficits in those who binge eat Given the distinction between three facets of emotion, namely subjective experience, behaviour and physiology, it is striking that physiological evidence of emotion regulatory ability in individuals who binge is lacking. This project aims to clarify the emotion regulatory ability in young women who engage in bingeing behaviours using the startle eyeblink paradigm. The unique contribution of emotion-based dispositions to rash action (positive and negative urgency) and reward and punishment sensitivity to these behaviours will also be examined.
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Alcohol, Hypomania and Impulsivity
This study investigates the relationship between personality traits, substance use, and alcohol expectancies. Individuals higher on hypomania have also been shown to be higher on personality traits such as impulsivity and sensation seeking. People higher on any of these traits have been shown to use more substances and have more substance related problems than those lower on these traits. While alcohol expectancies have been related to alcohol use, the relationship with hypomanic personality is unclear. This study examines mediators and moderators related to hypomanic personality.
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Bipolar Actigraph Study
This study will measure baseline and 6-month follow-up clinical, cognitive and electrophysiological functioning in patients with Bipolar Disorder. During the intervening 6 months, participants will wear an actigraph (which measures motor activity levels) at all times. We anticipate that baseline EEG and motor activity will predict the onset of a mood episode in participants with Bipolar Disorder.
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PPI SPQ Study
This study examines whether dimensional measures of personality risk for schizophrenia-spectrum disorders and externalizing psychopathology are differentially related to the visual and auditory P3. Reduction in amplitude of the P3 event-related potential component has been proposed as genetic risk marker for both schizophrenia and externalizing disorders. However, it is presently unclear whether the auditory and visual P3 amplitude reductions reflect a cognitive risk factor common to both classes of disorder or that risk for schizophrenia is specifically associated with processes contributing to auditory P3, while risk for externalizing is associated with processes more strongly associated with visual P3. We administer two personality questionnaires and record EEGs while participants perform two laboratory tasks.
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Distraction(!) and Visual Memory
The purpose of this behavioural study is to investigate whether the presentation of a distracter during a memory task affects recognition of visual stimuli, and whether visual or auditory distracters impact performance in different ways. Recent studies have found that distracters presented early during a delay period have the largest effect on memory encoding. Subjects will complete three personality questionnaires, a computer-based memory task, and some general tests of cognition and memory.
