A computational analysis of flanker interference in depression. Issue 11 (August 2015)

• Record Type: Journal Article
• Authors: Dillon, D. G.; Wiecki, T.; Pechtel, P.; Webb, C.; Goer, F.; Murray, L.; Trivedi, M.; Fava, M.; McGrath, P. J.; Weissman, M.; Parsey, R.; Kurian, B.; Adams, P.; Carmody, T.; Weyandt, S.; Shores-Wilson, K.; Toups, M.; McInnis, M.; Oquendo, M. A.; Cusin, C.; Deldin, P.; Bruder, G.; Pizzagalli, D. A.
• Is Part Of: Psychological medicine. Volume 45:Issue 11(2015)
• Page Start: 2333
• Page End: 2344
• Publication Date: 2015-08
• Subjects: Psychiatry -- Periodicals; Medicine and psychology -- Periodicals; Clinical psychology -- Periodicals; 616.89
• DOI: 10.1017/S0033291715000276
• Languages: English
• ISSNs: 0033-2917

Abstract

<abstract abstract-type="normal"> <title> <x content-type="archive" xml:space="preserve">Abstract</x> </title> <sec id="sec_a1"> <title>Background</title> <p>Depression is characterized by poor executive function, but – counterintuitively – in some studies, it has been associated with highly accurate performance on certain cognitively demanding tasks. The psychological mechanisms responsible for this paradoxical finding are unclear. To address this issue, we applied a drift diffusion model (DDM) to flanker task data from depressed and healthy adults participating in the multi-site Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC) study.</p> </sec> <sec id="sec_a2" sec-type="methods"> <title>Method</title> <p>One hundred unmedicated, depressed adults and 40 healthy controls completed a flanker task. We investigated the effect of flanker interference on accuracy and response time, and used the DDM to examine group differences in three cognitive processes: prepotent response bias (tendency to respond to the distracting flankers), response inhibition (necessary to resist prepotency), and executive control (required for execution of correct response on incongruent trials).</p> </sec> <sec id="sec_a3" sec-type="results"> <title>Results</title> <p>Consistent with prior reports, depressed participants responded more slowly and accurately than controls on incongruent trials. The DDM indicated that although executive control was sluggish in depressed participants, this was more than offset by decreased prepotent response bias. Among the depressed participants, anhedonia was negatively correlated with a parameter indexing the speed of executive control (<italic>r</italic> = −0.28, <italic>p</italic> = 0.007).</p> </sec> <sec id="sec_a4" sec-type="conclusion"> <title>Conclusions</title> <p>Executive control was delayed in depression but this was counterbalanced by reduced prepotent response bias, demonstrating how participants with executive function deficits can nevertheless perform accurately in a cognitive control task. Drawing on data from neural network simulations, we speculate that these results may reflect tonically reduced striatal dopamine in depression.</p> </sec> </abstract>