This study is part of a larger overall study that seeks to characterize clinical and pharmacological neuroimaging biomarkers. The purpose of this registered protocol is understand the effect of emotion on cognitions by specifically examining the effect of reward processing on working memory in patients with schizophrenia.
Cognition rarely occurs in the 'real world' in isolation, and typically occurs under emotional influences that may alter how cognition occurs. Understanding these motivational and cognitive interactions will help better assess mechanisms that underlie the cognitive and negative symptoms of schizophrenia. To better understand the effect of emotion on cognitions, this study will examine the effect of reward processing on working memory in patients with schizophrenia. To this end, this will be a two-pronged approach. The first prong, is to understand the neural mechanisms of incentivized spatial working memory processes. fMRI will be used and a paradigm will be employed that combines reward processing and working memory to understand how patients with schizophrenia recruit neural systems in response to rewarded working memory. To further understand this, this study will compare the neural effects in patients with schizophrenia with patients with depression, another group of psychiatric patients who also suffer from cognitive and motivational deficits. Both of these groups suffer from cognitive and motivational deficits, yet the treatments and disease presentations differ. It is hypothesized that the ways in which cognitive and motivational processes interact in the brain will have some similarities, but also differences, that distinguish the two psychiatric illnesses. As part of this aim, a group of typical, healthy adults subjects will be recruited as a control. A subset of healthy participants that passed the medical and psychiatric screen will be invited to participate in the ketamine portion of the study which will be completed during the MRI session.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
143
Magnetic Resonance Research Center
New Haven, Connecticut, United States
Working Memory (WM)
The tool used to measure working memory (WM) is a spatial working memory task. We measure angular accuracy of spatial working memory, and better accuracy is indicated by a lower angular distance. Subjects are asked to centrally fixate, and a circle appears on the screen briefly, and then disappears. Afterwards they see a gray circle that is linked to a joystick and are asked to move the gray circle to where they best remembered the initial circle to be. We care about the angular distance between where the initial circle appeared and where they placed the gray circle. The low range is 0 degrees, and the high range is 180 degrees. Scores are presented as averages and standard deviations.
Time frame: Up to 2 hours
Behavior
The tool used to measure behavior is a spatial working memory task. We measure angular accuracy of spatial working memory, and better accuracy is indicated by a lower angular distance. We expect that patients with schizophrenia would have higher angular distances (ie, worse accuracy) than healthy control subjects on placebo, and patients with ASD. We expect that HCS on ketamine would have higher angular distances (ie worse accuracy), compared to when they are not on ketamine, and that this would approach the performance of patients with SCZ. The low range is 0 degrees, and the high range is 180 degrees. Scores are presented as averages and standard deviations.
Time frame: Up to 2 hours
BOLD
Regional BOLD (blood oxygen dependent) signal in the dorsolateral prefrontal cortex and parietal cortex. BOLD signal refers to the blood oxygen level dependent signal change measured using functional magnetic resonance imaging. It is an indirect marker of neural activity. The time series of BOLD signal changes is entered into a general linear model with our events of interest (WM maintenance) and we do statistics on the resulting beta weights.
Time frame: Up to 2 hours
Whole brain connectivity
Whole-brain connectivity refers to the correlation in time series between voxels. These analysis will specifically focus on the delay period subjects are maintaining a spatial location.
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Time frame: Up to 2 hours