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bioRxiv · 10.1101/2023.02.17.529035

Visuomotor activity associated with conditioned hand movements in premotor cortex of blindsight macaques

Yamamoto, Y.·Kitazume, S.·Takahashi, J.·Onoe, H.·Yamaguchi, R.·Isa, T.
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Abstract

Some patients with damage to the primary visual cortex (V1) can respond to visual stimuli in their affected visual field, even though they report loss of visual awareness. This phenomenon is termed blindsight. To clarify the visuomotor transformation for hand movement control in the blindsight condition, we conducted multichannel electrocorticographical recordings from the ipsilesional frontal cortex including the frontal eye field, premotor, primary motor, and somatosensory areas during a delayed conditioned two-alternative forced choice manual response task with arbitrary assignment of push-pull manual responses in relation to the visual target cue locations before and after unilateral V1 lesioning in macaque monkeys. Before lesioning, the activity in the dorsal premotor cortex (PMd) showed short latency task-related {theta} ~ band responses that were significantly higher in the successful trials than in the error/miss trials at approximately 200 ms after target cue onset. At 2-3 months after lesioning, the monkeys regained a >80% success rate in response to appearance of the target cue in the lesion-affected visual field. At this stage, similar task-related {theta} ~ band target cue responses were observed in the PMd. Further, Granger causality from the PMd to the primary motor cortex was enhanced in the {theta} ~ , {gamma}, and high-{gamma} bands during the delay period of the task. These results suggested that the PMd plays a crucial role in mediating the visual signals for execution of hand movements in blindsight monkeys. Significant StatementBlindsight is a curious phenomenon in which the patients with damage to the primary visual cortex can still respond to visual stimulus in their blinded visual field despite loss of awareness. Previously we clarified the critical circuits for visually guided saccadic eye movements in blindsight macaques, however, those for the control of hand movements are still unclear. Here, we have recorded the multichannel electrocorticography in the frontal cortices during the conditioned manual response task and found that the dorsal premotor cortex exhibits task-related {theta} ~ band target cue responses at approximately 200 ms after the visual cue onset, similarly to the intact state. This is the first report of electrophysiological recordings in the frontal lobe of the blindsight subjects.

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Yamamoto, Y., Kitazume, S., Takahashi, J., Onoe, H., Yamaguchi, R., Isa, T.. 2023-02-18. Visuomotor activity associated with conditioned hand movements in premotor cortex of blindsight macaques. https://doi.org/10.1101/2023.02.17.529035

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