Neurocognitive and neurophysiological correlates of motor planning during familiar and novel contexts.

OBJECTIVE Research suggests that behavioral indices of motor planning (i.e., latencies that precede motor output) (a) relate to processing speed (PS) and executive functioning (EF), but not working memory (WM), and (b) deteriorate in novel contexts. It is not clear whether an electrophysiological index of motor planning (i.e., movement-related cortical potentials; MRCPs) also relates to PS and EF, and whether it deteriorates in novel contexts. This study sought to clarify associations among these variables while manipulating contextual novelty. METHOD Forty healthy adults completed standardized measures of PS, EF, and WM. Participants performed highly familiar motor sequences in familiar versus novel contexts during EEG recording, while motor planning latencies and peak MRCPs were obtained. Hierarchical regressions assessed the relative contributions of PS, EF, and WM to motor planning latencies and MRCPs. RESULTS Novel contexts elicited longer planning latencies (gav = 1.96) and reduced MRCPs (gav = .24) compared to familiar contexts. PS predicted planning times in both familiar (R² = .12) and novel contexts (R² = .15), while EF contributed additional variance during novel contexts only (R² Change = .10). EF was the sole predictor of MRCPs in both familiar (R² = .12) and novel contexts (R² = .18). WM did not predict planning latencies or MRCPs. CONCLUSIONS Contextual novelty alone can decrease performance and neural activation during complex sequencing. The general link between preparatory activation and EF suggests that capacity limitations drive novelty effects, and implies a common substrate underlying motor planning and higher-order behavioral control.