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Amarender Bogadhi, Leor Katz, Anil Bollimunta, Richard Krauzlis; A node for hemi-spatial neglect in macaque temporal cortex. Journal of Vision 2018;18(10):1219. doi: https://doi.org/10.1167/18.10.1219.
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© ARVO (1962-2015); The Authors (2016-present)
Studies of hemi-spatial neglect in humans have emphasized fronto-parietal and temporal cortical contributions to spatial attention along with several sub-cortical areas. Fronto-parietal and sub-cortical areas causally contribute to covert spatial attention in monkeys, but evidence that temporal cortex contributes to covert spatial attention is lacking. Here, we show that reversible inactivation of functionally identified mid-STS region during a covert attention task leads to performance deficits akin to hemi-spatial neglect. We trained monkeys in a covert attention task consisting of "Attend" and "Ignore" conditions. A central cue instructed the animal to either attend or ignore peripheral motion stimuli. The task of the animal was to maintain central fixation and to report the relevant stimulus change event by releasing a lever to get a juice reward. In Attend trials, the relevant event was the peripheral motion-direction change. In Ignore trials, the relevant event was dimming of the central fixation point while the peripheral motion-direction change was irrelevant and should be ignored. Pairing fMRI with reversible inactivation of Superior Colliculus (SC) during the covert attention task, we identified the mid-STS region (aFST) whose attention-related modulation was reduced during SC inactivation. To test if this region contributes causally, we reversibly inactivated aFST by injecting 4 – 6μl of muscimol during the covert attention task. We performed a total of 6 muscimol and 3 saline/sham control experiments. Reversible inactivation of aFST led to significant performance deficits in detecting stimulus changes in the contralateral hemi-field during the Attend condition. Furthermore, control experiments showed that the performance deficits for the contralateral stimulus cannot be fully explained by the effect of muscimol on motion processing. Our results show that inactivation of mid-STS region (aFST) leads to attention-related deficits akin to hemi-spatial neglect, hence revealing a temporal cortical node for hemi-spatial neglect in monkeys during a covert attention task.
Meeting abstract presented at VSS 2018
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