Dataset Information

Functional magnetic resonance imaging of a parametric working memory task in schizophrenia: relationship with performance and effects of antipsychotic treatment.

ABSTRACT:

Rationale

Working memory dysfunction is frequently observed in schizophrenia. The neural mechanisms underlying this dysfunction remain unclear, with functional neuroimaging studies reporting increased, decreased or unchanged activation compared to controls.

Objectives

We investigated the neural correlates of spatial working memory in schizophrenia with particular consideration of effects of antipsychotic treatment and relation to performance levels in the patient group.

Method

We used functional magnetic resonance imaging and studied the blood-oxygen-level-dependent (BOLD) response of 45 schizophrenia outpatients and 19 healthy controls during a parametric spatial n-back task.

Results

Performance in both groups deteriorated with increasing memory load (0-back, 1-back, 2-back), but the two groups did not significantly differ in performance overall or as a function of load. Patients produced stronger BOLD signal in occipital and lateral prefrontal cortex during task performance than controls. This difference increased with increasing working memory load in the prefrontal areas. We also found that in patients with good task performance, the BOLD response in left prefrontal cortex showed a stronger parametric increase with working memory load than in patients with poor performance. Second-generation antipsychotics were independently associated with left prefrontal BOLD increase in response to working memory load, whereas first-generation antipsychotics were associated with BOLD decrease with increasing load in this area.

Conclusions

Together, these findings suggest that in schizophrenia patients, normal working memory task performance may be achieved through compensatory neural activity, especially in well-performing patients and in those treated with second-generation antipsychotics.

SUBMITTER: Ettinger U

PROVIDER: S-EPMC3111549 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Publications

Functional magnetic resonance imaging of a parametric working memory task in schizophrenia: relationship with performance and effects of antipsychotic treatment.

Ettinger Ulrich U Williams Steven C R SC Fannon Dominic D Premkumar Preethi P Kuipers Elizabeth E Möller Hans-Jürgen HJ Kumari Veena V

Psychopharmacology 20110218 1

<h4>Rationale</h4>Working memory dysfunction is frequently observed in schizophrenia. The neural mechanisms underlying this dysfunction remain unclear, with functional neuroimaging studies reporting increased, decreased or unchanged activation compared to controls.<h4>Objectives</h4>We investigated the neural correlates of spatial working memory in schizophrenia with particular consideration of effects of antipsychotic treatment and relation to performance levels in the patient group.<h4>Method< ...[more]

PMID: 21331519

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Project description:BackgroundCognitive impairments are core characteristics of schizophrenia, but are largely resistant to current treatments. Several recent studies have shown that high-frequency repetitive transcranial magnetic stimulation (rTMS) of the left dor-solateral prefrontal cortex (DLPFC) can reduce negative symptoms and improve certain cognitive deficits in schizophrenia patients. However, results are inconsistent across studies.AimTo examine if high-frequency rTMS of the DLPFC can improve visual memory deficits in patients with schizophrenia.MethodsForty-seven chronic schizophrenia patients with severe negative symptoms on stable treatment regimens were randomly assigned to receive active rTMS to the DLPFC (n = 25) or sham stimulation (n = 22) on weekdays for four consecutive weeks. Patients performed the pattern recognition memory (PRM) task from the Cambridge Neuropsychological Test Automated Battery at baseline, at the end of rTMS treatment (week 4), and 4 wk after rTMS treatment (week 8). Clinical symptoms were also measured at these same time points using the Scale for the Assessment of Negative Symptoms (SANS) and the Positive and Negative Syndrome Scale (PANSS).ResultsThere were no significant differences in PRM performance metrics, SANS total score, SANS subscores, PANSS total score, and PANSS subscores between active and sham rTMS groups at the end of the 4-wk treatment period, but PRM performance metrics (percent correct and number correct) and changes in these metrics from baseline were significantly greater in the active rTMS group at week 8 compared to the sham group (all P < 0.05). Active rTMS treatment also significantly reduced SANS score at week 8 compared to sham treatment. Moreover, the improvement in visual memory was correlated with the reduction in negative symptoms at week 8. In contrast, there were no between-group differences in PANSS total score and subscale scores at either week 4 or week 8 (all P > 0.05).ConclusionHigh-frequency transcranial magnetic stimulation improves visual memory and reduces negative symptoms in schizophrenia, but these effects are delayed, potentially due to the requirement for extensive neuroplastic changes within DLPFC networks.

Dataset Information

Functional magnetic resonance imaging of a parametric working memory task in schizophrenia: relationship with performance and effects of antipsychotic treatment.

Rationale

Objectives

Method

Results

Conclusions

Publications

Functional magnetic resonance imaging of a parametric working memory task in schizophrenia: relationship with performance and effects of antipsychotic treatment.

Similar Datasets

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