Psychological Medicine



Abnormal neural response to feedback on planning and guessing tasks in patients with unipolar depression


R. ELLIOTT a1c1, B. J. SAHAKIAN a1, A. MICHAEL a1, E. S. PAYKEL a1 and R. J. DOLAN a1
a1 From the Wellcome Department of Cognitive Neurology, Institute of Neurology and Royal Free Hospital School of Medicine, London; and Department of Psychiatry, University of Cambridge

Abstract

Background. It has been suggested that patients with unipolar depression show abnormal responses to negative feedback in the performance of cognitive tasks. Positron emission tomography (PET) has previously identified blood flow abnormalities in depressed patients during cognitive performance. We have also used PET to identify regions where there is differential neural response to performance feedback in normal volunteers. In this study we aimed to test the hypothesis that blood flow in these regions, the medial caudate and ventromedial prefrontal cortex, would be abnormal in depressed patients.

Methods. Six patients with unipolar depression and six matched controls were scanned using PET while performing cognitive tasks in the presence and absence of feedback.

Results. Compared with controls, depressed patients failed to show significant activation in the medial caudate and ventromedial orbitofrontal cortex. Blood flow was lower and a differential response, observed in normals, under different task and feedback conditions was not seen in the patients.

Discussion. The findings suggest that the behavioural response to feedback in depressed patients is associated with an abnormal neural response within the medial caudate and ventromedial orbitofrontal cortex, regions implicated in reward mechanisms. We argue that the observed abnormalities may depend on a combination of psychological factors, with both cognitive and emotive components.


Correspondence:
c1 Address for correspondence: Dr Rebecca Elliott, Wellcome Department of Cognitive Neurology, 12 Queen Square, London WC1N 3BG.


Metrics
Related Content