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Brittany Dungan, Edward Vogel; Stable Visual Working Memory Representations Across Changes in Eye Position. Journal of Vision 2012;12(9):173. doi: 10.1167/12.9.173.
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© ARVO (1962-2015); The Authors (2016-present)
We perceive a stable visual world despite changes in eye position that cause objects to shift from one visual field to the other. One theory is that we use visual working memory (VWM) to integrate object information from across fixations. However, given the contralateral organization of VWM in the brain, it’s unclear how eye position changes that cause remembered objects to shift across visual fields would affect which hemisphere will continue to maintain the object information. This could occur in two ways. A "shift" account predicts that the objects in VWM would initially be represented in the contralateral hemisphere, but would then shift to the opposite hemisphere following the change in eye position. Alternatively, a "hold" account predicts that the objects would continue to be represented in the initial contralateral hemisphere despite the change in eye position. To test this, we recorded event related potentials while subjects performed a change detection task with 2 or 4 colored squares. Subjects began all trials fixating a central cross prior to the presentation of the memory array. For 50% of trials, subjects maintained central fixation throughout the entire trial. For the other 50% of trials, they were cued to refixate a new position that was 7 degrees to the left or right of central fixation during the middle of the retention period, thus bringing the objects into a new visual field. The results showed a sustained contralateral delay activity (CDA) that persisted in the original contralateral hemisphere even after the subjects had refixated. A subsequent control experiment in which subjects fixated laterally prior to object onset, confirmed that these results were not due to the CDA being spatiotopically organized. Together these results support a "hold" account in which item representations remain stable in the initial encoding hemisphere despite later changes in eye position.
Meeting abstract presented at VSS 2012
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