Illuminating Neocortical-Hippocampal Interactions - Elucidating Widefield Cortical Dynamics of Sensory Cue Processing during Sharp-Wave Ripple Events

Date
2023-10-11
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Abstract

Sensory cue consolidation is critical for the survival of animals, involving a variety of neural processes occurring in multiple brain regions. On a mesoscale, different Ca2+ reactivation patterns manifest across the neocortex when learning new sensory cues, while changes in task-related neuronal assembly between the prefrontal and hippocampus are observed during awake sharp-wave ripple (SWR) events, which play a crucial role in consolidation. Despite these insights, the wide-scale correlations between different brain regions during hippocampal activity following sensory stimulation remain poorly understood. To bridge this gap, we conducted a multimodal study using co-implantation of a near-cortex wide polymer window and longitudinal neural nanoelectronic threads (NETs) implanted in the CA1 of the hippocampus. By simultaneously recording neocortical-hippocampal activity during periods of visual stimulation and non-stimulation, our goal was to elucidate the correlations between multiple brain regions during hippocampal activity, specifically awake SWRs, in both visual and non-visual stimulation epochs. We mapped the different Ca2+ correlations between 28 cortical regions during a sharp wave ripple event in sequential periods of visual stimulation and zero-stimulus stimulation. Our findings revealed that during an SWR event, all brain regions exhibit changes in their correlation coefficients with one another in pre-visual versus post-visual zero-stimulus stimulation periods. Most notably, the pre-motor and visual regions of the neocortex display the largest change in correlation (α < 0.05) with all other brain regions during post-visual and pre-visual zero-stimulation stages. Furthermore, the sum of all correlations for each brain region and their eigen-centrality become more significant in post-visual zero-stimulus periods compared to pre-visual zero visual stimulation. These results suggest that distinct functional dynamics emerge between different brain regions during an SWR event in a period of no stimulation after visual stimulation. This has significant implications for future research on the mechanisms underlying sensory perception and the roles of various brain regions in this process. Additionally, our innovative approach using co-implantation of a near-cortex wide polymer window and NETs in a visual regime offers a potent tool for simultaneously investigating neural activity across multiple brain regions during sensory processing.

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EMBARGO NOTE: This item is embargoed until 2024-08-01
Degree
Master of Science
Type
Thesis
Keywords
Widefield Activity, Sharp-Wave Ripples, Neuro-imaging, Optical Imaging, Co-recording
Citation

Noble, Brian Christopher. "Illuminating Neocortical-Hippocampal Interactions - Elucidating Widefield Cortical Dynamics of Sensory Cue Processing during Sharp-Wave Ripple Events." (2023) Master's thesis, Rice University. https://hdl.handle.net/1911/115338

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