Dissociating effector and movement direction selection during the preparation of manual reaching movements: Evidence from lateralized ERP components

Objective The present study investigated whether lateralized ERP components triggered during covert manual response preparation (ADAN, LDAP) reflect effector selection, the selection of movement direction, or both. Methods Event-related brain potentials were recorded during a response precueing paradigm where visual cues provided either partial (Experiment 1) or full (Experiment 2) information about the response hand and the direction for a subsequent reaching movement. Results ADAN and LDAP components were elicited even when only partial response information was available, demonstrating that they do not require the presence of a fully specified motor program. The ADAN was elicited in a similar fashion regardless of whether effector or movement direction information was provided, suggesting that the underlying mechanisms are equally sensitive to both types of response-related information. In contrast, the LDAP was larger in response to cues providing effector information, but was also reliably present when movement direction was available. Conclusions ADAN and LDAP components reflect preparatory activity within anterior and posterior parts of the parieto-premotor sensorimotor network where different parameters for manual reaching movements are programmed independently. Significance These results support the claim of the premotor theory of attention that shared sensorimotor control mechanisms are involved in attention and motor programming.