Movement-related EEG indices of preparation in task switching and motor control.

Lateralized readiness potential (LRP) and time-frequency domain LRP-type measures, called motor-related amplitude asymmetries (MRAA), in the mu band (9-13 Hz; mu-MRAA) and the beta band (18-26 Hz; beta-MRAA) were used to study the time course of preparation in a task-switching task and a response precuing task. Several dissociations between LRP and mu-MRAA and beta-MRAA were found. Mu-MRAA and beta-MRAA, but not LRP, exhibited an early and strong reversal in cortical lateralization when advance preparation for a switch of response hand was required. LRP, but not mu-MRAA or beta-MRAA, was sensitive to manipulation of the probability that advance preparation of response hand would be useful in a response precuing task. These dissociations replicate earlier findings and suggest that movement-related cortical rhythms and cortical potentials are associated with distinct preparatory component processes that differ in terms of level of abstraction and effort, in line with similar functional distinctions between component processes underlying executive control in task switching. This suggests that a fine-grained analysis of subprocesses involved in motor control may provide important guiding principles for the study and understanding of levels and mechanisms of cognitive control.