Description
- Abstract:
- The guiding hypothesis for this thesis is that the posterior parietal cortex (PPC) integrates sensory information from visual and somatosensory areas in order to plan appropriate actions. Such actions are modulated by attentional demands communicated to the PPC through its connections with the lateral posterior nucleus of the thalamus (LPO) in the rodent brain. I addressed this hypothesis using anatomical, behavioral, and electrophysiological techniques combined with optogenetic manipulation in a rodent behavioral model of visuospatial attention. I first developed a novel behavioral task, the Visuospatial Attention (VSA) task, in which stimuli are limited to the visual and spatial domains. This task allows assessment of visuospatial attention and action selection. Versions of this task were used for the three electrophysiological studies. In the first study, I recorded neuronal activity in the dorsal PPC during performance on the VSA task. This experiment revealed cellular correlates of attention and action selection. In the second study, I inspected anatomical connections of the dorsal and caudal PPC with the LPO and the postrhinal cortex. This experiment showed that rodent-primate connectional homology of the PPC extends to the dorsal and caudal PPC subdivisions in the rat. In the third study, I simultaneously recorded different subdivisions of the rat PPC including both dorsal and caudal limbs as well as the LPO. This study addressed the question of whether the connectional homology across PPC subdivisions extends to the functions of the subdivisions. In the final study, I combined the electrophysiology and optogenetic manipulations to examine the influence of the LPO input on the dorsal and caudal PPC. This final study provided additional evidence that these three regions are part of a functional circuit. This series of studies advances our basic understanding of the role of the PPC in the circuitry that supports visuospatial attention. These studies further developed the rodent model of attention by elucidating the contributions of the caudal PPC and its role in these circuits. Finally, a more complete rodent model will be advantageous for understanding and treating human disorders relevant to the PPC, such as hemispatial neglect, and attentional alterations in various mental disorders.
- Notes:
- Thesis (Ph.D.)--Brown University, 2017
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Citation
Yang, Fang-Chi,
"Thalamocortical Circuits and Visuospatial Attention"
(2017).
Psychology Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0736PB9
