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Katherine Bettencourt, Yaoda Xu; Understanding the nature of visual short-term memory representation in human parietal cortex. Journal of Vision 2015;15(12):292. doi: 10.1167/15.12.292.
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© ARVO (1962-2015); The Authors (2016-present)
Recent work has shown that the human parietal cortex, in particular superior intraparietal sulcus (IPS), plays a central role in visual short-term memory (VSTM) storage. However, much remains unknown about the nature of these memory representations including whether they are similar or distinct from perceptual representations. Using fMRI multivariate pattern analysis (MVPA), it has been shown that VSTM representations in occipital cortex are highly similar to perceptual representations. Here, we tested whether the same would be true for VSTM representations in superior IPS. On the one hand, VSTM representations in superior IPS could simply be an extension of the sensory representations formed during perception. This would predict a high degree of similarity between VSTM and perceptual representations in this region. However, we have previously shown that VSTM representations in superior IPS, unlike those in occipital cortex, are robust to visual distraction. This suggests that the nature of VSTM representation in the two regions may differ, and that representations in superior IPS may be consolidated and thus, distinct from perceptual representations. In the present study, we had participants complete both a VSTM and perceptual task using face and gazebo stimuli. We then decoded between the two stimuli types both within a task and across the two tasks. To minimize any attention or memory effects in the perceptual task, participants performed a one back letter task at fixation. Pilot results showed decoding of both memory and perceptual information in superior IPS, and, importantly, successful cross decoding between the two tasks. This suggests that, just like in occipital cortex, VSTM information in superior IPS is represented in a similar manner to perceptual information.
Meeting abstract presented at VSS 2015
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