A Functional Magnetic Resonance Imaging Study of Working Memory Abnormalities in Schizophrenia

Matthew R. Johnson, Nicholas A. Morris, Robert S. Astur, Vince D. Calhoun, Daniel H. Mathalon, Kent A. Kiehl, Godfrey D. Pearlson

Research output: Contribution to journalArticle

99 Scopus citations

Abstract

Background: Previous neuroimaging studies of working memory (WM) in schizophrenia, typically focusing on dorsolateral prefrontal cortex, yield conflicting results, possibly because of varied choice of tasks and analysis techniques. We examined neural function changes at several WM loads to derive a more complete picture of WM dysfunction in schizophrenia. Methods: We used a version of the Sternberg Item Recognition Paradigm to test WM function at five distinct loads. Eighteen schizophrenia patients and 18 matched healthy controls were scanned with functional magnetic resonance imaging at 3 Tesla. Results: Patterns of both overactivation and underactivation in patients were observed depending on WM load. Patients' activation was generally less responsive to load changes than control subjects', and different patterns of between-group differences were observed for memory encoding and retrieval. In the specific case of successful retrieval, patients recruited additional neural circuits unused by control subjects. Behavioral effects were generally consistent with these imaging results. Conclusions: Differential findings of overactivation and underactivation may be attributable to patients' decreased ability to focus and allocate neural resources at task-appropriate levels. Additionally, differences between encoding and retrieval suggest that WM dysfunction may be manifested differently during the distinct phases of encoding, maintenance, and retrieval.

Original languageEnglish (US)
Pages (from-to)11-21
Number of pages11
JournalBiological Psychiatry
Volume60
Issue number1
DOIs
StatePublished - Jul 1 2006

Keywords

  • Dorsolateral prefrontal cortex
  • Sternberg task
  • fMRI
  • memory load
  • schizophrenia
  • working memory

ASJC Scopus subject areas

  • Biological Psychiatry

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    Johnson, M. R., Morris, N. A., Astur, R. S., Calhoun, V. D., Mathalon, D. H., Kiehl, K. A., & Pearlson, G. D. (2006). A Functional Magnetic Resonance Imaging Study of Working Memory Abnormalities in Schizophrenia. Biological Psychiatry, 60(1), 11-21. https://doi.org/10.1016/j.biopsych.2005.11.012