Conversely, if a task-relevant stimulus places low demands on the perceptual system, spare capacity becomes available to process unattended distractors 21, 22 and 23].

Experiments exploiting this framework typically involve a central target and peripheral distractors, a scenario akin to keeping focused on the traffic warden at a crossing while still being able to detect a child who strays onto the opposite side of the road. The amount of processing appropriated to unattended distractors can be inferred from the magnitude of fMRI repetition suppression associated with distractor repetition [24]. The availability of resources for processing unattended stimuli can be manipulated by varying the perceptual clarity of the central target. Consistent with a state related reduction in peripheral processing capacity, sleep deprivation attenuated repetition suppression to peripheral pictures when central perceptual Selleckchem Erismodegib load was high but not when perceptual load was low [25]. This contrasts with the situation with rested participants where sufficient capacity is available such that perceptual load has no significant effect on repetition suppression (Figure 2A). Selective attention can be dissociated into enhancement

of task-relevant information, and suppression of distractions/task-irrelevant information 26 and 27]. By keeping sensory input constant and manipulating PLX4032 manufacturer the object of attention using ambiguous, overlapping face and house pictures [28], target facilitation and distractor suppression can be dissociated [29•]. In addition to the robust finding that PPA activation is reduced by SD, there is a selective deficit in suppression of PPA activation to ignored houses, sparing enhancement of PPA activation

to attended houses [29•] (Figure 2B). This observation parallels studies of cognitive aging that highlight similar deficits check details in distractor suppression 30, 31 and 32]. Suppressing distraction and keeping to task goals can be thought of as an executive function with perceptual consequences, for example, in the case of deficient filtering of target memoranda during tests of visual short-term memory [33] or with increased head turns toward peripheral distracting events during SD [34]. The ability to maintain a sensory representation for several seconds is crucial for enabling goal-directed behavior and is a core feature of attention [35]. This function is served by a capacity-limited visual short-term memory (VSTM). Most individuals are only able to store about four visual items at a time [36]. If short-term memoranda fail to be maintained over brief delays, critical items that we need queued for this manipulation task will be unavailable, thus degrading higher order cognitive functions which require access to such memoranda.