Changes in the endogenous and task-dependent effective connectivity were assessed by DCM of a bilateral network comprising M1, lateral premotor cortex, and the supplementary motor area (SMA).
In such endogenous cuing tasks, orienting toward the likely target location is very much top-down in origin, since it depends on the effort invested by the participant.
A "validity effect" in endogenous and exogenous task conditions for each participant was derived from response times to valid and invalid cues.
In the case of the easy task, endogenous attention might not be necessary because the target may pop out, causing an exogenous, stimulus-driven shift of attention.
Crucially, it can be applied to experimentally evoked responses (activation studies) or endogenous activity in task-free (resting state) fMRI studies.
To investigate the central claim made by the premotor theory of attention that attention shifts and saccade preparation are mediated by shared control mechanisms, we recorded ERPs under conditions in which central symbolic spatial cues indicated the direction of a covert endogenous attentional shift (Covert task), the direction of an upcoming eye movement (Saccade task) or both (Combined task).
Finally, experimental paradigms in which the target and distractor are not defined a priori, since there is no explicit task directing endogenous attention to any particular element on the screen, also inform about the extent of the automaticity with which emotional stimuli access attentional resources.
A more parsimonious explanation is that post-task changes in endogenous dynamics are directly related to difficulty of task performance.
Fifteen participants completed a point-light biological motion study following a two-by-two factorial design, with one factor representing an exogenous manipulation of human movement goals (goal-directed versus random movement), and the other an endogenous manipulation (a goal identification task versus an ancillary color-change task).
Behavioural results have demonstrated that the effect of endogenous spatial orienting varies with task demands (i.e. increases with probability of cue validity), while effects of exogenous cues are independent of cue validity [12].
