Refining the time course of facilitation and inhibition in attention and action.

According to action-centred models of attention, there is a tight coupling between attention and response planning processes. In support of these models, previous research has shown that reach trajectories deviate towards a cue at short (<100ms) cue-target onset asynchronies (CTOAs) and away from a cue presented at longer CTOAs (>750ms). These deviations resemble the pattern of facilitatory and inhibitory reaction time (RT) effects observed in keypress studies. Here, participants reached to targets following a non-predictive cue and 5 CTOAs (from 100 to 600ms in 125ms intervals) were used to gain a deeper understanding of the relationship between RT and trajectory effects. Consistent with action-centred attention, facilitatory and inhibitory cuing after-effects were present in RTs and trajectories. Interestingly, RT and trajectory effects were temporally staggered: facilitatory effects were present in trajectories at the 100ms CTOA when they had already dissipated in RTs, and inhibitory effects were present in RTs (≥350ms CTOAs) before they were detected in trajectories (600ms CTOA). The time courses of the cuing effects suggest that, although action and attention systems are tightly coupled, the facilitatory and inhibitory mechanisms operate in attention before affecting action planning.