Enhanced feature tuning for saccade targets in foveal but not peripheral visual neurons

Each saccadic eye movement brings peripheral targets to the fovea for inspection. Before each saccade, visual neurons with peripheral receptive fields overlapping the target show enhancements in firing. Previously, we examined neural tuning of peripheral MT neurons during this pre-saccadic attention. We found gain enhancements that were uniform across motion direction consistent with neural studies of covert attention. However, pre-saccadic attention is also thought to involve feature-specific perceptual enhancements concentrated around the saccade target’s features (Li, Barbot, & Carrasco, 2016; Ohl, Kuper, & Rolfs, 2017). Here we examined if feature-specific enhancements might occur in foveal representations where the target is anticipated. We recorded from MT neurons with foveal receptive fields as marmoset monkeys performed a saccade to one of three equally eccentric motion dot fields. During saccade flight we manipulated the motion direction of the saccade target to test if post-saccadic responses were biased towards its predicted motion. In “predictive” trials the stimulus was unchanged during the saccade while in “unexpected” trials we swapped its motion for an orthogonal direction (+/- 90 degrees). If foveal representations exhibited feature-specific enhancements for the target then we would expect enhanced tuning for the predicted targets. We find that for predicted trials MT neurons increase their response around the preferred motion direction while suppressing non-preferred directions. These findings show that saccades can produce feature-specific enhancements in post-saccadic foveal processing that favor processing for the predicted target. This mechanism could support continuity of target selection across the saccades.