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Elizabeth Lorenc, Kartik Sreenivasan, Annelinde Vandenbroucke, Mark D'Esposito; Effects of distractors on visual working memory representations. Journal of Vision 2016;16(12):703. doi: 10.1167/16.12.703.
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© 2017 Association for Research in Vision and Ophthalmology.
Visual working memory (VWM) allows for the maintenance of precise visual details of objects no longer in view, and is supported by activity in many brain regions, including lateral prefrontal cortex (D'Esposito et al., 1995, 1996) and primary sensory cortices (Harrison & Tong, 2009). While "sensory recruitment" models (D'Esposito, 2007; Postle, 2006) suggest that precise visual details are maintained in stimulus-selective primary visual regions, it remains unclear what happens to VWM representations in the face of subsequent visual input. In this experiment, we examine whether, and where, tuned VWM representations persist through an irrelevant distractor, and whether subsequent VWM orientation tuning is biased toward the orientation of the distractor. Functional magnetic resonance imaging (fMRI) data was collected while participants performed a delayed-estimation task for right-lateralized oriented gratings. On 2/3 of trials, a distractor grating appeared midway through the 20-s trial in the same spatial location as the initial memory cue, rotated between 40 and 50° clockwise or counterclockwise of the remembered orientation. We employed a forward encoding modeling approach (Brouwer & Heeger, 2011; Ester et al., 2013) to reconstruct orientation tuning functions reflecting the accuracy and precision of orientation representations during 1) stimulus perception, 2) memory maintenance, 3) distractor perception, and 4) memory maintenance following distraction. Reliable orientation tuning was observed during stimulus perception in the contralateral, but not ipsilateral, early visual areas (V1-V3). However, the representations spread to bilateral V1-V3 over the memory maintenance interval. During distractor presentation, tuning for the remembered orientation persisted in both hemispheres, although tuning was considerably weakened in the hemisphere contralateral to the distractor. Finally, the tuning curves in bilateral V1-V3 were biased toward the distractor orientation after the distractor offset, and there was a small but significant behavioral bias in the same direction.
Meeting abstract presented at VSS 2016
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