Increased repulsion of working memory representations in schizophrenia.

Area of Science:

• Cognitive Neuroscience
• Computational Psychiatry
• Neuroscience of Schizophrenia

Background:

• Working memory (WM) models propose recurrent excitation and lateral inhibition for stable representations.
• Behavioral studies suggest lateral inhibition causes repulsion of WM representations.
• Computational models of schizophrenia hypothesize reduced inhibition underlies cognitive deficits.

Purpose of the Study:

• To test the hypothesis that people with schizophrenia spectrum disorders (PSZ) exhibit reduced WM repulsion effects compared to healthy controls (HCS).
• To investigate the role of inhibition in cognitive impairments associated with schizophrenia spectrum disorders.

Main Methods:

• Two experiments were conducted to measure WM repulsion effects in PSZ and HCS.
• Experiment 1: Participants remembered object location relative to a landmark.
• Experiment 2: Participants remembered sequentially presented orientations.

Main Results:

• Both groups showed repulsion effects in WM tasks.
• PSZ exhibited significantly increased repulsion effects compared to HCS in both experiments.
• Findings contradict the hypothesis of reduced inhibition in schizophrenia spectrum disorders.

Conclusions:

• Behavioral evidence from two experiments demonstrates exaggerated, not reduced, competitive inhibition in PSZ.
• These findings challenge the prevailing computational models of schizophrenia that link cognitive impairment to reduced inhibition.
• The study highlights a potential over-activation of inhibitory mechanisms in working memory for individuals with schizophrenia spectrum disorders.