Response complexity and precue interval effects on the lateralized readiness potential.

Fundamental properties of an important new tool in cognitive electrophysiology, the lateralized readiness potential (LRP), were examined in two experiments. Experiment 1 resolved an apparent inconsistency in the literature by demonstrating that this response-specific lateralization is larger preceding complex then preceding simple finger movements. In Experiment 2, the foveally presented precue, which indicated hand of response, preceded the go/no-go stimulus by 0, 100, 300, or 1,400 ms. Analyses of LRP latency indicated that hand-specific preparation began earlier with longer foreperiods but was temporally linked to the reaction stimulus as well as the precue. Although the degree of lateralization did not predict reaction speed in either study, a nonlateralized, response-locked negativity was larger prior to faster reactions.