You covertly shift your attention to a location in your left visual field without moving your eyes. Before any stimulus appears there, what changes in your visual cortex?
ANothing — visual cortex only responds once a stimulus actually appears; anticipatory activity is handled by prefrontal regions.
BNeurons whose receptive fields cover the attended location increase their baseline firing rate, preparing the cortex to respond more strongly if a stimulus appears.
CThe attended location is suppressed to reduce noise, improving signal-to-noise ratio when a stimulus eventually arrives.
DEye-movement motor programs are activated in the frontal eye fields, even though no eye movement occurs.
This is the key finding that defines attention as gain control. Top-down signals from the frontal eye field increase baseline firing rates in V1, V2, and V4 at the attended location even before a stimulus appears. When a stimulus does appear, it drives stronger, more reliable responses because the cortex was already prepared. This anticipatory amplification — not passive stimulus reception — is what makes attention a predictive mechanism. Option A is wrong because it treats visual cortex as passive; option C gets the mechanism backwards (attended locations are amplified, not suppressed; unattended ones are suppressed).
Question 2 Multiple Choice
Patients with right hemisphere parietal damage often exhibit hemispatial neglect — failing to attend to stimuli on their left side. What does this reveal about the role of parietal cortex in attention?
AParietal cortex is the primary storage site for visual memories, and neglect reflects a loss of memory for left-side objects.
BRight parietal cortex is specialized for left-side stimulus processing because of the visual field crossing, so damage eliminates left-field perception.
CParietal cortex transforms spatial attention signals into coordinates usable for orienting and action; its damage disrupts the mapping of attention to contralateral space.
DNeglect reflects motor paralysis — patients cannot move their eyes leftward, so they fail to perceive left-side stimuli.
Posterior parietal cortex (including the temporoparietal junction) converts attention-related spatial signals from retinal or head-centered coordinates into formats that guide covert orienting, reach, and grasp — connecting 'where to attend' to 'where to act.' The right hemisphere's parietal cortex is strongly lateralized, managing attention to contralateral (left) space. Damage disrupts this transformation, not basic visual processing or motor control: neglect patients can see (optics intact) and move their eyes (no paralysis) but fail to orient attention to the left side of space.
Question 3 True / False
The frontal eye fields (FEF) modulate activity in visual cortex even when no eye movement is made, through top-down signals that prepare attention at specific locations.
TTrue
FFalse
Answer: True
While the FEF is classically known as a saccade control region, it sends preparatory 'priority map' signals to visual areas during covert attention — directing processing toward behaviorally relevant locations without moving the eyes. This is a central finding: the source of attention control signals is frontoparietal, not within visual cortex itself. Visual cortex is the target of top-down modulation, not the origin of the attention signal. This dissociation between 'where to look' circuits and 'where to covertly attend' circuits is fundamental to understanding the neural architecture of attention.
Question 4 True / False
Unattended visual locations are merely processed with lower priority than attended ones — the brain allocates fewer resources to them but does not actively suppress them.
TTrue
FFalse
Answer: False
The Explainer explicitly states that unattended locations are not merely deemphasized — they are actively suppressed, particularly when they contain distractors. This active suppression is distinct from simply allocating fewer resources. At attended locations, receptive fields effectively shrink and sharpen; at unattended locations (especially those with competing stimuli), neural responses are actively driven down. This active suppression is part of what makes spatial attention effective at filtering distractors rather than merely amplifying targets.
Question 5 Short Answer
Explain how temporal attention and spatial attention reveal the same underlying principle about how the brain handles sensory input.
Think about your answer, then reveal below.
Model answer: Both spatial and temporal attention demonstrate that the brain does not passively receive sensory input — it actively prepares for expected inputs by allocating processing resources before stimuli arrive. Spatial attention increases neural firing rates at attended locations before a stimulus appears there, so that if a stimulus arrives, the cortex is primed to respond. Temporal attention, when stimulus onset is rhythmically predictable, entrains neural oscillations in visual cortex so that the excitability peak aligns to the expected stimulus time. In both cases, the mechanism is predictive amplification: expectation shapes sensory processing in advance, coupling perception to anticipation.
The unifying principle across spatial and temporal attention is that the brain uses prior knowledge (about location or timing) to bias its own sensory processing before the stimulus arrives. This anticipatory allocation of resources is what makes attention the mechanism through which expectation and perception are coupled — attention is not just a filter applied after input arrives but a preparatory state that shapes how input is received.