Neural markers of automatic and controlled attention during immediate and delayed action.

It has been shown that visually guided and memory-guided actions are under the control of dissociable neural systems. This experiment measured event-related potentials (ERPs) in a cross-modal dual-task paradigm to investigate the attentional requirements of these two types of actions. In a primary joystick-controlled continuous reciprocal aiming task, participants moved a cursor back and forth between two targets of variable size in visually guided (VIS) and memory-guided (MEM) conditions. In a secondary dichotic listening task, ERPs were collected while infrequent high and frequent low pitch tones were delivered to both ears. Participants responded to the infrequent tones delivered to only one attended ear. Aiming and listening were performed separately and together as a dual task. We were interested in two ERP components: the P300 component, which reflects voluntary attention, and the mismatch negativity (MMN), which reflects automatic attention. The results showed that the P300 component elicited by the auditory task was decreased in amplitude by the dual-task conditions compared with the auditory task alone. Moreover, P300 latency was increased by the MEM aiming condition, but not the VIS aiming condition. On the other hand, the MMN component elicited by the auditory task was only attenuated by the VIS aiming condition, not by the MEM aiming condition. Together, these results suggest that memory-guided aiming requires more voluntary attention and less automatic attention than visually guided aiming.