Authors:

MURPHY, F.C., Michael, A., Robbins, T.W., Sahakian, B.J

Reference:

Year of publication:

2003

CBU number:

5503

Abstract:

Background: Recent evidence suggests that an abnormal response to performance feedback may contribute to the wide-ranging neuropsychological deficits typically associated with depressive illness. The present research sought to determine whether the inability of depressed patients to utilise performance feedback advantageously is equally true for accurate and misleading feedback. Methods: Patients with major depression and matched controls completed: (1) a visual discrimination and reversal task that featured intermittent and misleading negative feedback, and (2) feedback and no-feedback versions of a computerised test of spatial working memory. In the feedback version, negative feedback was accurate, highly informative, and could be used as a mnemonic aid. Results: On the Probability Reversal task, depressed patients were impaired in their ability to maintain response set in the face of misleading negative feedback as shown by their increased tendency to switch responding the the ‘incorrect’ stimulus following negative reinforcement, relative to that of controls. Patients’ ability to acquire and reverse that necessary visual discrimination was unimpaired. On the Spatial Working Memory task, depressed patients made significantly more between-search errors than controls and adopted a less efficient search strategy, but their ability to use negative feedback to facilitate performance remained intact. Conclusions: The present results suggest that feedback can have different effects in different contexts. Misleading, negative feedback appears to disrupt the performance of depressed patients, whereas negative but accurate feedback does not. These findings are considered in the context of recent studies on reinforcement systems and their associated neurobiological substrates.