Eye position effects on the remapped memory trace of visual motion in cortical area MST.

Naoko Inaba,Kenji Kawano

doi:10.1038/srep22013

Abstract

After a saccade, most MST neurons respond to moving visual stimuli that had existed in their post-saccadic receptive fields and turned off before the saccade (“trans-saccadic memory remapping”). Neuronal responses in higher visual processing areas are known to be modulated in relation to gaze angle to represent image location in spatiotopic coordinates. In the present study, we investigated the eye position effects after saccades and found that the gaze angle modulated the visual sensitivity of MST neurons after saccades both to the actually existing visual stimuli and to the visual memory traces remapped by the saccades. We suggest that two mechanisms, trans-saccadic memory remapping and gaze modulation, work cooperatively in individual MST neurons to represent a continuous visual world.

Highlights

Because of saccadic eye movements, images of the visual scene rapidly sweep across the retina and thereby shift to different retinal locations
We recently reported that after a saccade, most medial superior temporal (MST) neurons responded to a visual stimulus that had pre-existed inside their post-saccadic receptive fields (RFs) and turned off before the saccade (i.e., “memory remapping”)[25]
We found that the visual sensitivity of MST neurons after the saccades was modulated by the gaze angle both to the real visual stimuli and to the visual memory traces

Summary

Introduction

Because of saccadic eye movements, images of the visual scene rapidly sweep across the retina and thereby shift to different retinal locations Despite such blurring and displacement of the retinal images, we are able to perceive the visual world as stable and continuous. Neurons whose visual responses are modulated by eye position, so called “eye position gain field”, have been observed in areas LIP, medial superior temporal (MST), middle temporal (MT), ventral intraparietal (VIP), and 7a16–21 These areas are hypothesized to form inputs to the spatiotopic map of the visual scene[22,23,24]. In this context, the neural correlates of the two proposed mechanisms that address the saccade displacement problem, trans-saccadic remapping and spatiotopic representation have been reported in various areas. Remapped by the saccades, suggesting their role in constructing a stable and continuous visual world despite saccadic eye movements

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