Abstract
In natural vision humans and other primates explore environment by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and in the medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry that is modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using recordings in the human thalamus of three surgical patients during natural vision, we found that saccades and visual stimulus onset both modulate neural activity, but with distinct field potential morphologies. Specifically, we found that fixation-locked field potentials had a component that preceded saccade onset. It was followed by an early negativity around 50 ms after fixation onset which is significantly faster than any response to visual stimulus presentation. The timing of these events suggests that the ANT is predictively modulated before the saccadic eye movement. We also found oscillatory phase concentration, peaking at 3–4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80–180 Hz), both locked to fixation onset supporting the idea that neural oscillations in these nuclei are reorganized to a low excitability state right after fixation onset. These findings show that during real-world natural visual exploration neural dynamics in the human ANT is influenced by visual and oculomotor events, which supports the idea that ANT, apart from their contribution to episodic memory, also play a role in natural vision.
Item Type: | Journal article |
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EU Funded Grant Agreement Number: | 802681 |
EU Projects: | Horizon 2020 > ERC Grants > ERC Starting Grant > ERC Grant 802681: DirectThalamus - How the human thalamus guides navigation and memory: a common coding framework built on direct thalamic recordings |
Faculties: | Psychology and Education Science > Department Psychology |
Research Centers: | Graduate School of Systemic Neurosciences (GSN) |
Subjects: | 100 Philosophy and Psychology > 150 Psychology |
URN: | urn:nbn:de:bvb:19-epub-77636-3 |
Language: | English |
Item ID: | 77636 |
Date Deposited: | 25. Oct 2021, 14:08 |
Last Modified: | 25. Oct 2021, 14:08 |