Dorsal Premotor Cortex and Conditional Rule Resolution: A High-Frequency TMS Investigation

Behavior that is contingent on conditional rules necessitatesan abstraction away from concrete stimulus-response identi-ties in order to form a rule template, but also a subsequenttransformation of representation back into sensorimotor for-mat in order to produce concrete behavior. Evidence suggeststhat dorsal premotor cortex (PMd) is well-positioned to me-diate such an operation. We utilized repetitive transcranialmagnetic stimulation, a non-invasive manner of perturbing thefunctioning of targeted cortical regions, to investigate the roleof dorsal premotor cortex during performance of a Rapid In-structed Task Learning paradigm. The task required partici-pants to form conditional associations between stimuli and re-sponses carrying varying levels of abstraction. Selective inter-ference of response times to stimuli presentation was observedonly when the task necessitated the participants to resolve aconditional response referring to an internally-produced repre-sentation of a rule element with relatively abstracted quality.We conclude that PMd specifically supports conditional rulebehavior through transformation of abstract representations toconcrete response, when the conditional rule necessary to re-solve includes abstract, internally-produced identities.