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Psychol Med. 2008 Aug;38(8):1185-93. doi: 10.1017/S0033291708003565. Epub 2008 May 29.

Failure to deactivate in the prefrontal cortex in schizophrenia: dysfunction of the default mode network?

Author information

  • 1Benito Menni Complex Assistencial en Salut Mental, Barcelona, Spain. edith.pomarol@gmail.com

Abstract

BACKGROUND:

Functional imaging studies using working memory tasks have documented both prefrontal cortex (PFC) hypo- and hyperactivation in schizophrenia. However, these studies have often failed to consider the potential role of task-related deactivation.

METHOD:

Thirty-two patients with chronic schizophrenia and 32 age- and sex-matched normal controls underwent functional magnetic resonance imaging (fMRI) scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.

RESULTS:

The controls showed activation in the expected frontal regions. There were also clusters of deactivation, particularly in the anterior cingulate/ventromedial PFC and the posterior cingulate cortex/precuneus. Compared to the controls, the schizophrenic patients showed reduced activation in the right dorsolateral prefrontal cortex (DLPFC) and other frontal areas. There was also an area in the anterior cingulate/ventromedial PFC where the patients showed apparently greater activation than the controls. This represented a failure of deactivation in the schizophrenic patients. Failure to activate was a function of the patients' impaired performance on the n-back task, whereas the failure to deactivate was less performance dependent.

CONCLUSIONS:

Patients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task. The area of failure of deactivation is in the anterior prefrontal/anterior cingulate cortex and corresponds to one of the two midline components of the 'default mode network' implicated in functions related to maintaining one's sense of self.

PMID:
18507885
[PubMed - indexed for MEDLINE]
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