Computational and neurobiological mechanisms underlying cognitive flexibility

doi:10.1073/pnas.0509550103

Computational and neurobiological mechanisms underlying cognitive flexibility

David Badre*,^†,^‡ and
Anthony D. Wagner*

*Department of Psychology and Neurosciences Program, Stanford University, Stanford, CA 94305; and
^†Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307

Edited by Edward E. Smith, Columbia University, New York, NY, and approved March 14, 2006 (received for review November 2, 2005)

Abstract

The ability to switch between multiple tasks is central to flexible behavior. Although switching between tasks is readily accomplished, a well established consequence of task switching (TS) is behavioral slowing. The source of this switch cost and the contribution of cognitive control to its resolution remain highly controversial. Here, we tested whether proactive interference arising from memory places fundamental constraints on flexible performance, and whether prefrontal control processes contribute to overcoming these constraints. Event-related functional MRI indexed neural responses during TS. The contributions of cognitive control and interference were made theoretically explicit in a computational model of task performance. Model estimates of two levels of proactive interference, “conceptual conflict” and “response conflict,” produced distinct preparation-related profiles. Left ventrolateral prefrontal cortical activation paralleled model estimates of conceptual conflict, dissociating from that in left inferior parietal cortex, which paralleled model estimates of response conflict. These computationally informed neural measures specify retrieved conceptual representations as a source of conflict during TS and suggest that left ventrolateral prefrontal cortex resolves this conflict to facilitate flexible performance.

Footnotes

^‡To whom correspondence should be addressed at:
Helen Wills Neuroscience Institute, 132 Barker Hall, Mail Code 3120, Berkeley, CA 94720-3120.
E-mail: dbadre{at}berkeley.edu
Author contributions: D.B. and A.D.W. designed research; D.B. performed research; D.B. analyzed data; and D.B. and A.D.W. wrote the paper.
↵ § Meyer, D. E., Lauber, E. J., Rubinstein, J., Gmeindl, L., Junck, L. & Koeppe, R. A., Poster Presented at the Annual Meeting of the Cognitive Neuroscience Society, April 5-7, 1998, San Francisco.
Conflict of interest statement: No conflicts declared.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

Abbreviations:

VLPFC,

ventrolateral prefrontal cortex;

SMA,

supplementary motor area;

fMRI,

functional MRI;

RT,

response time;

TS,

task switch/switching;

CAM-TS,

control of associative memory during TS;

CSI,

cue-to-stimulus interval;

RCI,

time from the previous response until cue presentation;

RR,

response repetition;

RS,

response same;

RD,

response different;

ROI,

region of interest