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Noninvasive Characterization of Functional Pathways in Layer-Specific Microcircuits of the Human Brain Using 7T fMRI

Deshpande, G and Wang, Y (2022) Noninvasive Characterization of Functional Pathways in Layer-Specific Microcircuits of the Human Brain Using 7T fMRI. In: Brain Sciences, 12 (10).

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Official URL: https://doi.org/10.3390/brainsci12101361


Layer-specific cortical microcircuits have been explored through invasive animal studies, yet it is not possible to reliably characterize them functionally and noninvasively in the human brain. However, recent advances in ultra-high-field functional magnetic resonance imaging (fMRI) have made it feasible to reasonably resolve layer-specific fMRI signals with sub-millimeter resolution. Here, we propose an experimental and analytical framework that enables the noninvasive functional characterization of layer-specific cortical microcircuits. Specifically, we illustrate this framework by characterizing layer-specific functional pathways in the corticogeniculate network of the human visual system by obtaining sub-millimeter fMRI at 7T using a task which engages the magnocellular pathway between the lateral geniculate nucleus (LGN) and the primary visual cortex. Our results demonstrate that: (i) center-surround inhibition in magnocellular neurons within LGN is detectable using localized fMRI responses; (ii) feedforward (LGN → layers VI/IV, layer IV → layer VI) and feedback (layer VI → LGN) functional pathways, known to exist from invasive animal studies, can be inferred using dynamic directional connectivity models of fMRI and could potentially explain the mechanism underlying center-surround inhibition as well as gain control by layer VI in the human visual system. Our framework is domain-neutral and could potentially be employed to investigate the layer-specific cortical microcircuits in other systems related to cognition, memory and language.

Item Type: Journal Article
Publication: Brain Sciences
Publisher: MDPI
Additional Information: The copyright for this article belongs to the Author(S).
Keywords: animal experiment; animal model; article; cognition; controlled study; functional magnetic resonance imaging; human; language; lateral geniculate body; memory; nerve cell; nonhuman; striate cortex; visual system
Department/Centre: Autonomous Societies / Centres > Centre for Brain Research
Date Deposited: 09 Nov 2022 06:11
Last Modified: 09 Nov 2022 06:11
URI: https://eprints.iisc.ac.in/id/eprint/77820

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