Inter-areal Communication in Posterior Parietal Cortex Supporting Eye-hand and Bimanual Coordination
ORCID
https://orcid.org/0000-0002-3724-5138
Date of Award
8-24-2023
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Understanding inter-areal communication is crucial for systems neuroscience. Much of the processing in the brain involves communication between different areas. Sensory areas must send information to motor areas, and motor areas must communicate with each other if different body parts are to be coordinated. For example, coordinating movements of the two arms likely requires interactions between motor areas in the two hemispheres. We therefore hypothesize that bimanual and eye-hand coordination relies on interhemispheric communication, and the most direct path for information exchange between the two hemispheres is through the corpus callosum. By reversibly blocking the callosal pathways connecting the left and right cortices and recording neural activity before, during, and after blockade in each hemisphere, we can evaluate the contributions of interhemispheric communication to neuronal processing and behavior during bimanual and eye-hand coordination, which we entitle “hand-eye-hand” (HEH) coordination. We aim to investigate the early planning of bimanual movements, and the role of interareal and interhemispheric communication between effector-specific areas in the posterior parietal cortex in HEH coordination. The parietal reach region (PRR) primarily codes the early planning of contralateral arm movements, and interhemispheric communication between PRR in each hemisphere is a possible mechanism for one arm to “know” the movement of the other arm. The lateral intraparietal area (LIP) is an analogous area that primarily codes eye movements or visual saliency in its contralateral hemifield, and we predict that inter-areal communication between LIP and PRR may be important for eye-hand coordination. Eye-hand coordination. We ask whether LIP plays a central role in allocating spatial resources (spatial attention) during coordinated eye and arm movements. We measured effective connectivity between PRR and LIP to test their relative roles. If LIP is a “command center” for spatial decision-making, then information should flow from LIP to PRR when identifying a target for a reach. In contrast, if LIP subserves an oculomotor function, then information should flow reciprocally between LIP and PRR to support eye-hand coordination. We simultaneously measured spikes and local field potentials (LFP) in PRR and LIP during coordinated eye and arm movements. Inter-areal spike-LFP coherence and LFP-LFP spectral Granger causality analyses indicate that twice as much information flows from PRR to LIP than vice versa. This is consistent with PRR playing a commanding role in determining the spatial goal of a reach and instructing LIP of that decision. Our results suggest that area LIP primarily subserves an oculomotor function rather than a “command center” for spatial processing.
Language
English (en)
Chair and Committee
Lawrence Snyder
Recommended Citation
Kang, Jung Uk, "Inter-areal Communication in Posterior Parietal Cortex Supporting Eye-hand and Bimanual Coordination" (2023). Arts & Sciences Electronic Theses and Dissertations. 3152.
https://openscholarship.wustl.edu/art_sci_etds/3152