Brain activation during executive processes in schizophrenia

Royer, Aurélie; Schneider, F.; Grosselin, Anne; Pellet, Jacques; Barral, Fabrice-Guy; Laurent, Bernard; Brouillet, Denis; Lang, François

doi:10.1016/j.pscychresns.2009.02.009

Cited by 31 publications

(17 citation statements)

References 53 publications

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“…Bearing in mind that the patients have psychotic symptoms and general clinical impairments, this pattern suggests the operation of compensatory neural mechanisms that led to overall successful task performance when compared to healthy controls. A number of previous studies have similarly observed compensatory BOLD increases on the background of comparable task performance in schizophrenia patients (Karch et al 2009; Lee et al 2008; Potkin et al 2009; Royer et al 2009; Tan et al 2005; van Raalten et al 2008; see also meta-analysis by Minzenberg et al 2009). However, while the patients' recruitment of additional areas in our study may represent a behaviourally successful compensatory mechanism, it is also neurally inefficient as it requires additional resources in order to achieve a comparable performance levels as the controls.…”

Section: Discussionmentioning

confidence: 86%

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

et al. 2011

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RationaleWorking 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.ObjectivesWe 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.MethodWe 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.ResultsPerformance 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.ConclusionsTogether, 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.Electronic supplementary materialThe online version of this article (doi:10.1007/s00213-011-2214-7) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 86%

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

et al. 2011

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“…Earlier EEG and fMRI studies also revealed hyperfrontality combined with increased parietal activity in patients with first-episode psychosis during working memory tasks. 10,[51][52][53][54] It is thus likely that the early activation of parietal generators in attentional tasks observed in our study may represent a compensatory mechan ism 55 to facilitate the maintenance of executive performances in patients with first-episode psychosis.…”

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confidence: 79%

Event-related potentials and changes of brain rhythm oscillations during working memory activation in patients with first-episode psychosis

Missonnier

Herrmann

Zanello

et al. 2012

J Psychiatry Neurosci

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Background: Earlier contributions have documented significant changes in sensory, attention-related endogenous event-related potential (ERP) components and theta band oscillatory responses during working memory activation in patients with schizophrenia. In patients with first-episode psychosis, such studies are still scarce and mostly focused on auditory sensory processing. The present study aimed to explore whether subtle deficits of cortical activation are present in these patients before the decline of working memory performance. Methods: We assessed exogenous and endogenous ERPs and frontal theta event-related synchronization (ERS) in patients with first-episode psychosis and healthy controls who successfully performed an adapted 2-back working memory task, including 2 visual n-backworking memory tasks as well as oddball detection and passive fixation tasks. Results: We included 15 patients with first-episode psychosis and 18 controls in this study. Compared with controls, patients with first-episode psychosis displayed increased latencies of early visual ERPs and phasic theta ERS culmination peak in all conditions. However, they also showed a rapid recruitment of working memory-related neural generators, even in pure attention tasks, as indicated by the decreased N200 latency and increased amplitude of sustained theta ERS in detection compared with controls. Limitations: Owing to the limited sample size, no distinction was made between patients with first-episode psychosis with positive and negative symptoms. Although we controlled for the global load of neuroleptics, medication effect cannot be totally ruled out. Conclusion: The present findings support the concept of a blunted electroencephalographic response in patients with first-episode psychosis who recruit the maximum neural generators in simple attention conditions without being able to modulate their brain activation with increased complexity of working memory tasks

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“…On the 1-back and 2-back tasks, participants had to press the left button when the letter on the current trial matched the letter 1 or 2 trials back, and had to press the right button for all other letters. The 2-back task has been shown to reliably activate the DLPFC in HC and SZ participants (Haut et al 2010; Royer et al, 2009). In order to specifically measure neural activity related to 2-back working memory demands, we contrasted activity on 2-back working-memory trials with 0-back visual attention trials.…”

Section: Methodsmentioning

confidence: 99%

Intensive cognitive training in schizophrenia enhances working memory and associated prefrontal cortical efficiency in a manner that drives long-term functional gains

et al. 2014

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We investigated whether intensive computerized cognitive training in schizophrenia could improve working memory performance and increase signal efficiency of associated middle frontal gyri (MFG) circuits in a functionally meaningful manner. Thirty schizophrenia participants and 13 healthy comparison participants underwent fMRI scanning during a letter N-back working memory task. Schizophrenia participants were then randomly assigned to either 80 hours (16 weeks) of cognitive training or a computer games control condition. After this intervention, participants completed a second fMRI N-back scanning session. At baseline, during 2-back working memory trials, healthy participants showed the largest and most significant activation in bilateral MFG, which correlated with task performance. Schizophrenia participants showed impaired working memory, hypoactivation in left MFG, and no correlation between bilateral MFG signal and task performance. After training, schizophrenia participants improved their 2-back working memory performance and showed increased activation in left MFG. They also demonstrated a significant association between enhanced task performance and right MFG signal, similar to healthy participants. Both task performance and brain activity in right MFG after training predicted better generalized working memory at 6-month follow-up. Furthermore, task performance and brain activity within bilateral MFG predicted better occupational functioning at 6-month follow-up. No such findings were observed in the computer games control participants. Working memory impairments in schizophrenia and its underlying neural correlates in MFG can be improved by intensive computerized cognitive training; these improvements generalize beyond the trained task and are associated with enduring effects on cognition and functioning 6 months after the intervention.

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Brain activation during executive processes in schizophrenia

Cited by 31 publications

References 53 publications

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

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

Event-related potentials and changes of brain rhythm oscillations during working memory activation in patients with first-episode psychosis

Intensive cognitive training in schizophrenia enhances working memory and associated prefrontal cortical efficiency in a manner that drives long-term functional gains

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