Motor programming of finger sequences of different complexity

In a response precuing task, we used behavioral and electrophysiological measures – Contingent Negative Variation (CNV) and the readiness potential (RP) – to investigate the programming of three-element response sequences of different complexity. Precuing effects on foreperiod CNV and RT indicated the use of advance information about response hand and response sequence. Crucially, with advance information about both hand and sequence, heterogeneous response sequences (e.g., 1 → 2 → 2) elicited larger foreperiod CNV activity over medial motor areas than homogeneous response sequences (e.g., 1 → 2 → 3), whereas CNV activity over lateral motor areas was not influenced by sequence complexity. It was only before response execution that lateral but not medial RP activity was stronger for heterogeneous than homogeneous response sequences. Both behavioral and electrophysiological measures indicated finger-order dependent influences on the duration of on-line response programming during response execution.

Research highlights▶ CNV activity is larger for hetero- than homogeneous response sequences ▶ Medial (SMA) but not lateral (M1) preparatory motor activity shows sequence effect ▶ M1 but not SMA activity shows response sequence effect at response execution ▶ Start finger and finger-order influence response execution time and M1 activity.