Evidence for the transient nature of a neural system supporting goal-directed action.

Disruption of a neural system supporting goal-directed action gives rise to lapses of intention in healthy individuals and disorganized behavior in patients with prefrontal lesions. Evidence from behavioral studies indicates that the occurrence of lapses in selective attention, working memory and prospective memory tasks is transient in nature. In the current study, we used event-related brain potentials to demonstrate that lapses are associated with a slow wave over the frontal region that begins well before stimulus onset and lasts for several hundred milliseconds. The magnitude of this slow wave was modulated by task demands, indicating that attentional processes can be flexibly allocated in the service of goal-directed action. Together the findings of these experiments indicate that lapses result from a transient inability to bring to bear the goals of the individual upon the action selection system.