Prefrontal cortex and flexible cognitive control: Rules without symbols

^*Department of Psychology, University of Colorado, 345 UCB, Boulder, CO 80309; ^†Institut National de Recherche en Informatique et en Automatique Lorraine, Campus Scientifique, B.P. 239, F-54506 Vandoeuvre-Lès-Nancy Cedex, France; ^‡Department of Electrical Engineering and Computer Science, Vanderbilt University, Vu Station B 351679, Nashville, TN 37235; ^§Department of Psychology, Washington University, Campus Box 1125, St. Louis, MO 63130-4899; and ^¶Department of Psychology, Princeton University, Green Hall, Princeton, NJ 08544

Communicated by James L. McClelland, Carnegie Mellon University, Pittsburgh, PA, March 29, 2005 (received for review February 3, 2005)

Abstract

Human cognitive control is uniquely flexible and has been shown to depend on prefrontal cortex (PFC). But exactly how the biological mechanisms of the PFC support flexible cognitive control remains a profound mystery. Existing theoretical models have posited powerful task-specific PFC representations, but not how these develop. We show how this can occur when a set of PFC-specific neural mechanisms interact with breadth of experience to self organize abstract rule-like PFC representations that support flexible generalization in novel tasks. The same model is shown to apply to benchmark PFC tasks (Stroop and Wisconsin card sorting), accurately simulating the behavior of neurologically intact and frontally damaged people.

Footnotes

↵ ∥ To whom correspondence should be addressed. E-mail: oreilly{at}psych.colorado.edu.
Author contributions: N.P.R., D.C.N., T.S.B., J.D.C., and R.C.O. designed research; N.P.R. and R.C.O. performed research; N.P.R. and R.C.O. analyzed data; and N.P.R., D.C.N., T.S.B., J.D.C., and R.C.O. wrote the paper.
Abbreviations: PFC, prefrontal cortex; WCST, Wisconsin Card Sort Task.