GABA concentration is reduced in visual cortex in schizophrenia and correlates with orientation-specific surround suppression

Jong H. Yoon, Richard J Maddock, Ariel Rokem, Michael A. Silver, Michael J. Minzenberg, John D Ragland, Cameron S Carter

Research output: Contribution to journalArticle

226 Scopus citations

Abstract

The neural mechanisms underlying cognitive deficits in schizophrenia remain essentially unknown. The GABA hypothesis proposes that reduced neuronal GABA concentration and neurotransmission results in cognitive impairments in schizophrenia. However, few in vivo studies have directly examined this hypothesis. We used magnetic resonance spectroscopy (MRS) at high field to measure visual cortical GABA levels in 13 subjects with schizophrenia and 13 demographically matched healthy control subjects. We found that the schizophrenia group had an ∼10%reduction inGABAconcentration.Wefurther tested theGABAhypothesis by examining the relationship between visual corticalGABAlevels and orientation-specific surround suppression (OSSS), a behavioral measure of visual inhibition thought to be dependent on GABAergic synaptic transmission. Previous work has shown that subjects with schizophrenia exhibit reduced OSSS of contrast discrimination (Yoon et al., 2009). For subjects with both MRS and OSSS data (n = 16), we found a highly significant positive correlation (r = 0.76) between these variables.GABAconcentration was not correlated with overall contrast discrimination performance for stimuli without a surround (r = -0.10). These results suggest that a neocortical GABA deficit in subjects with schizophrenia leads to impaired cortical inhibition and that GABAergic synaptic transmission in visual cortex plays a critical role in OSSS.

Original languageEnglish (US)
Pages (from-to)3777-3781
Number of pages5
JournalJournal of Neuroscience
Volume30
Issue number10
DOIs
StatePublished - Mar 10 2010

ASJC Scopus subject areas

  • Neuroscience(all)

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