Task-evoked substantia nigra hyperactivity associated with prefrontal hypofunction, prefrontonigral disconnectivity and nigrostriatal connectivity predicting psychosis severity in medication naïve first episode schizophrenia

Jong H. Yoon, Andrew J. Westphal, Michael Mizenberg, Tara Niendam, J. Daniel Ragland, Tyler Lesh, Marjorie Solomon, Cameron S. Carter

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

The widely cited prefrontal dysfunction - excess subcortical dopamine model of schizophrenia posits that prefrontal deficits give rise to cognitive impairments and the disinhibition of subcortical dopamine release underlying psychosis. While this has been one of the most influential schizophrenia models, only a handful of studies have provided evidence supporting it directly in patients with schizophrenia. We previously demonstrated task-evoked substantia nigra hyperactivity in the context of prefrontal hypofunction and prefrontonigral functional disconnectivity. In addition, nigrostriatal functional connectivity was identified as a potential marker of psychosis. Because patients in this prior study had chronic schizophrenia and were treated with antipsychotics, in the present study we tested whether these findings were confounded by illness chronicity and medication effects by seeking to reproduce these findings in an independent sample of antipsychotic naïve, first episode (FE) patients. We compared event-related fMRI activations from 12 FE patients with 15 demographically matched healthy control subjects during cognitive testing. We found substantia nigra hyperactivity associated with prefrontal hypofunction and prefrontonigral functional disconnectivity, as well as the magnitude of nigrostriatal functional connectivity positively correlating with severity of psychosis. This study adds to the body of evidence supporting the prefrontal-dopamine model of schizophrenia and further validates nigrostriatal functional connectivity as a marker of psychosis.

Original languageEnglish (US)
Pages (from-to)521-526
Number of pages6
JournalSchizophrenia Research
Volume159
Issue number2-3
DOIs
StatePublished - Nov 1 2014

Keywords

  • Basal ganglia
  • Dopamine
  • FMRI
  • Prefrontal cortex
  • Psychosis
  • Striatum
  • Substantia nigra

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry

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