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Abstract:
GOALS Growing evidence suggests an impairment at the level of
executive control functions in depression. The aim of this study
was to demonstrate a specific impairment of executive control in a
response inhibition task and to investigate its neurophysiological
correlate using event-related potentials.
METHODS We examined 16 patients with unipolar depression and 16
healthy controls using an auditory Go/Nogo task. High density (64
channels) event-related potentials (ERPs) were recorded. The task
was performed in a simple and a difficult condition to control for
effects due to general task difficulty.
RESULTS Depressive patients performed similar to controls in the
Go task, but worse in the Nogo task, which requires response
inhibition. ERPs allowed to address the neurophysiological
substrate of this dysfunction. Both groups showed the same voltage
pattern in the Go task. However, depressive patients showed reduced
N2 amplitude over fronto-temporal regions in the Nogo task. There
was no difference between groups in later stages of processing as
indexed by the P3 complex.
CONCLUSIONS Depressive patients showed a specific deficit in
response inhibition task. This deficit reflects dysfunctional
activation of the network subserving executive control during an
early stage of cortical processing.
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