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Anastasia Kiyonaga, Tobias Egner; Working memory representations produce inhibition of similar (but not identical) stimuli in visual attention. Journal of Vision 2015;15(12):544. doi: 10.1167/15.12.544.
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© ARVO (1962-2015); The Authors (2016-present)
Working memory (WM) maintenance can produce patterns of neural activity similar to visually-attended sensory stimuli, suggesting that WM and visual attention may share neural representations. If this is the case, an item in WM should impact behavior just like a visually-attended one. Here, we examine whether the center-surround selective tuning mechanism that is purported to focus attention in the visual system also applies to stimuli that are attended internally (i.e., in WM). When attention is directed at a particular stimulus, processing for that location or feature is enhanced, while nearby stimuli are inhibited. We test whether maintaining a color stimulus in WM produces inhibition, during a visual attention task, of nearby stimuli in color space. Participants viewed a colored WM sample whose shade was selected randomly from a circular color space (and then performed a change detection task on a subset of “catch trials”). During the WM delay, they completed a visual search wherein the targets and distractors (which were opposite each other on the color wheel) varied continuously in similarity to the WM sample. Targets could thus be an exact match to the WM item, or different in 10° steps. Visual search was fastest when the target was an exact WM match, and slowest when a distractor was an exact WM match, but similarity between the target and WM sample did not produce a linear effect on search speed. Instead, search was slowed when targets were similar in color to the WM sample (i.e., 10-30° away), then speeded again as targets became more dissimilar to the WM sample, and would presumably fall outside a suppressive surround. This suggests that focusing internal attention on a color in WM produced surround-inhibition that impaired visual processing for similar colors. WM and visual attention, thus, seem to activate the same representations.
Meeting abstract presented at VSS 2015
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