The spatial distribution of receptive field changes in a model of peri-saccadic perception: predictive remapping and shifts towards the saccade target.

摘要

At the time of an impending saccade receptive fields (RFs) undergo dynamic changes, that is, their spatial profile is altered. This phenomenon has been observed in several monkey visual areas. Although their link to eye movements is obvious, neither the exact pattern nor their function is fully clear. Several RF shifts have been interpreted in terms of predictive remapping mediating visual stability. In particular, even prior to saccade onset some cells become responsive to stimuli presented in their future, post-saccadic RF. In visual area V4, however, the overall effect of RF dynamics consists of a shrinkage and shift of RFs towards the saccade target. These observations have been linked to a pre-saccadically enhanced processing of the future fixation. In order to better understand these seemingly different outcomes, we analyzed the RF shifts predicted by a recently proposed computational model of peri-saccadic perception (Hamker, Zirnsak, Calow, & Lappe, 2008). This model unifies peri-saccadic compression, pre-saccadic attention shifts, and peri-saccadic receptive field dynamics in a common framework of oculomotor reentry signals in extrastriate visual cortical maps. According to the simulations that we present in the current paper, a spatially selective oculomotor feedback signal leads to RF dynamics which are both consistent with the observations made in studies aiming to investigate predictive remapping and saccade target shifts. Thus, the seemingly distinct experimental observations could be grounded in the same neural mechanism leading to different RF dynamics dependent on the location of the RF in visual space.