Related Experiment Videos
Prefrontal cortex dysfunction mediates deficits in working memory and prepotent responding in schizophrenia
William M Perlstein1, Neha K Dixit, Cameron S Carter
1Department of Clinical and Health Psychology and the McKnight Brain Institute, University of Florida, Gainesville, 32610, USA.
Biological Psychiatry
|January 7, 2003
Summary
Schizophrenic patients have impaired cognitive control, showing deficits in working memory (WM) and response inhibition. Brain imaging reveals reduced prefrontal cortex activity in these patients during demanding cognitive tasks.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Psychiatry
Background:
- Schizophrenia is associated with working memory (WM) and response inhibition deficits.
- Prefrontal cortex (PFC) dysfunction is implicated in these cognitive impairments.
- This study investigates overlapping PFC engagement in WM and response override tasks.
Purpose of the Study:
- To examine brain activity during working memory and response override tasks in schizophrenia.
- To test if these cognitive functions engage overlapping PFC regions.
- To determine if schizophrenic patients exhibit reduced PFC activity and performance deficits.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used.
- 16 schizophrenic and 15 healthy subjects performed N-Back (WM load) and AX-CPT (response override) tasks.
- Task demands were systematically varied.
Main Results:
- Both tasks activated overlapping cortical networks, including dorsolateral PFC and parietal cortex.
- Increased WM load and response override preparation enhanced activity.
- Schizophrenic subjects showed reduced right dorsolateral PFC activity and performance impairments under high cognitive load.
Conclusions:
- Schizophrenic patients exhibit PFC-mediated deficits in WM and response override.
- Findings support a single cognitive control mechanism mediated by the PFC.
- Physiologic dysfunction of the dorsolateral PFC contributes to these impairments in schizophrenia.