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Abstract:
Abstract: Patients with unipolar depression show selective
effects of emotional tone of material on speed and accuracy of
cognitive processing, with a bias towards mood-congruent
information. The aim of this study was to determine the neural
correlates of this effect. We performed a BOLD contrast fMRI study
of 11depressed patients and 11 control subjects during performance
of a go-no go task. In some conditions, subjects made responses on
the basis of emotional aspects of briefly presented words (respond
to "happy", "sad" or "neutral" words). In other conditions subjects
responded to orthographic aspects of words (bold or italic type).
Normal subjects showed neural response in left inferior frontal
gyrus and dorsal anterior cingulate when attending semantic rather
than orthographic features of words. Attending to emotionally toned
words was associated with response in the ventral anterior
cingulate. There were no significant differences between attending
happy and sad words. In depressed patients, the overall response to
word meaning was not significantly different. However they showed
enhanced response for emotional words compared to controls in the
right ventrolateral frontal cortex. This was particularly
pronounced for sad rather than happy words. We conclude that the
right ventral frontal cortex may mediate the bias towards
processing mood-congruent (sad) material in depressed
patients.
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