Purchase this article with an account.
Shanna Coop, Jacob Yates, Jude Mitchell; Enhanced neural tuning in middle temporal area (MT) of the marmoset monkey during pre-saccadic attention. Journal of Vision 2020;20(11):758. https://doi.org/10.1167/jov.20.11.758.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Recent psychophysical studies have described perceptual enhancements for the targets of saccades immediately prior to eye movements. These enhancements involve a sharpening of sensitivity around the target’s features consistent with feature gain (Li et al., 2016). Complementary neurophysiological studies have identified pre-saccadic enhancements in extra-striate cortex (Moore and Chang, 2009), but have not directly examined how neuronal tuning changes. We examined how neuronal tuning for motion direction in the middle temporal area (MT) of the marmoset monkey changed under pre-saccadic attention. Marmosets made a saccade from central fixation to one of several equally eccentric stimuli (full coherence motion dot fields). Marmosets were rewarded for selecting any of the targets, as long as their choice differed from the choice of the previous trial. For each trial, the direction of motion of each stimulus was independently sampled from 16 motion directions. MT responses were categorized based on whether the saccade was planned towards or away from the receptive field under study. Consistent with studies in macaque V4 (Moore & Chang, 2009), we find that neural sensitivity increases when the saccade is made towards the RF. We also examined changes in tuning curves by fitting an adjusted Von Mises function to the responses in each saccade (towards or away) condition. We find that neurons exhibit gain increase before saccades towards the RF, consistent with previous studies of covert attention (McAdams & Maunsell, 1999). However, while gain increases occurred across the epoch from 0 to 100 ms before the saccade, other aspects of tuning (narrowing and baseline shifts) varied. We found greater narrowing at earlier pre-saccadic epochs followed by more additive increases near saccade onset. These findings support recent psychophysics which suggests that pre-saccadic attention involves not only gain increases but also an automatic feature-selective gain for the saccade target.
This PDF is available to Subscribers Only