Cerebral Cortex Advance Access published online on November 13, 2009
Cerebral Cortex, doi:10.1093/cercor/bhp247
Neural Components Underlying Behavioral Flexibility in Human Reversal Learning
1 Department of Psychology, 2 Department of Psychiatry and Biobehavioral Sciences, 3 Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90065, USA
Address correspondence to Dara G. Ghahremani, PhD, Department of Psychology, Franz Hall, Box 951563, University of California, Los Angeles, Los Angeles, CA 90065, USA. Email: darag{at}ucla.edu.
The ability to flexibly respond to changes in the environment is critical for adaptive behavior. Reversal learning (RL) procedures test adaptive response updating when contingencies are altered. We used functional magnetic resonance imaging to examine brain areas that support specific RL components. We compared neural responses to RL and initial learning (acquisition) to isolate reversal-related brain activation independent of cognitive control processes invoked during initial feedback-based learning. Lateral orbitofrontal cortex (OFC) was more activated during reversal than acquisition, suggesting its relevance for reformation of established stimulus–response associations. In addition, the dorsal anterior cingulate (dACC) and right inferior frontal gyrus (rIFG) correlated with change in postreversal accuracy. Because optimal RL likely requires suppression of a prior learned response, we hypothesized that similar regions serve both response inhibition (RI) and inhibition of learned associations during reversal. However, reversal-specific responding and stopping (requiring RI and assessed via the stop-signal task) revealed distinct frontal regions. Although RI-related regions do not appear to support inhibition of prepotent learned associations, a subset of these regions, dACC and rIFG, guide actions consistent with current reward contingencies. These regions and lateral OFC represent distinct neural components that support behavioral flexibility important for adaptive learning.
Key Words: cognitive control • fMRI • orbitofrontal cortex • response inhibition • reversal learning