Increased repulsion of working memory representations in schizophrenia.

Sonia Bansal, Gi Yeul Bae, Kyle Frankovich, Benjamin M. Robinson, Carly J. Leonard, James M. Gold, Steven J. Luck

Research output: Contribution to journalArticlepeer-review

Abstract

Computational neuroscience models propose that working memory (WM) involves recurrent excitatory feedback loops that maintain firing over time along with lateral inhibition that prevents the spreading of activity to other feature values. In behavioral paradigms, this lateral inhibition appears to cause a repulsion of WM representations away from each other and from other strong sources of input. Recent computational models of schizophrenia have proposed that reduction in the strength of inhibition relative to strength of excitation may underlie impaired cognition, and this leads to the prediction that repulsion effects should be reduced in people with schizophrenia spectrum disorders (PSZ) relative to healthy control subjects (HCS). We tested this hypothesis in 2 experiments measuring WM repulsion effects. In Experiment 1, 45 PSZ and 32 HCS remembered the location of a single object relative to a centrally presented visual landmark and reported this location after a short delay. The reported location was repelled away from the landmark in both groups, but this repulsion effect was increased rather than decreased in PSZ relative to HCS. In Experiment 2, 41 PSZ and 34 HCS remembered 2 sequentially presented orientations and reported each orientation after a short delay. The reported orientations were biased away from each other in both groups, and this repulsion effect was again more pronounced in PSZ than in HCS. Contrary to the widespread hypothesis of reduced inhibition in schizophrenia, we provide robust evidence from 2 experiments showing that the behavioral performance of PSZ exhibited an exaggeration rather than a reduction of competitive inhibition. (PsycInfo Database Record (c) 2020 APA, all rights reserved) General Scientific Summary—Although spatial working memory impairments are among the hallmark neurocognitive deficits in people with schizophrenia (PSZ), the neural mechanisms are not well established. Formation of precise memory representations depends on the balance of excitatory and inhibitory processes, andthis balance is thought to be disrupted in schizophrenia. Here we show that interactions between working memory representations are exaggerated in people with PSZ, such that objects are remembered as being more dissimilar than they actually are, and counter to computational models emphasizing reduced inhibition in schizophrenia, these repulsion effects in PSZ are consistent with exaggerated competitive inhibition between similar representations of objects. (PsycInfo Database Record (c) 2020 APA, all rights reserved)

Original languageEnglish (US)
Pages (from-to)845-857
Number of pages13
JournalJournal of Abnormal Psychology
Volume129
Issue number8
DOIs
StatePublished - Nov 2020

Keywords

  • cognitive impairment
  • lateral inhibition
  • recurrent excitation
  • schizophrenia
  • working memory

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry

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