Date of Award

2026-05-01

Degree Name

Doctor of Philosophy

Department

Biological Sciences

Advisor(s)

Arshad M. Khan

Abstract

The neural control of energy balance is mediated in part by distributed brainstem circuits that integrate metabolic, visceral, and hormonal signals to coordinate appropriate motivated behaviors and autonomic responses. Despite extensive study, the precise neuroanatomical architecture regulating metabolism remains incompletely defined within standardized atlas frameworks. This work addresses that gap through complementary studies examining an acute glycemic challenge methodology known to stimulate feeding, the acute delivery of an anorexigenic-associated neurohormone, and the chemoarchitecture of a major feeding-related region, the parabrachial nucleus. First, utilizing 2-deoxy-D-glucose (2-DG) induced glucoprivation, we map the rapid response of dorsal medullary neuronal populations with high spatial resolution. These data reveal prominent recruitment of catecholaminergic populations implicated in glucose counterregulatory responses. Second, we examined the same medullary areas following hindbrain-directed OT transfusion at the same rapid time point post-treatment. OT was observed to induce rapid activation across several medullary domains, including the nucleus of the solitary tract (NTS), intermediate reticular formation (IRt), raphe obscurus (RO), and raphe pallidus (RPA), demonstrating substantial spatial overlap in the rapid recruitment of brainstem circuitry across opposing metabolic states. Third, we provide a chemoarchitectural analysis of the PB, a key integration center for processing of visceral and meal-related signals. By utilizing cross-subject consensus mapping within an atlas-aligned framework, we establish a structural basis for interpreting the chemical heterogeneity of the PB that lays the groundwork for future studies investigating its role in feeding suppression and aversive signaling. By integrating functional activation mapping with anatomical exploration, this work details anatomical dissection of the interconnected hindbrain circuits that regulate energy balance, with implications for targeting these pathways in obesity and metabolic disease.

Language

en

Provenance

Received from ProQuest

File Size

208 p.

File Format

application/pdf

Rights Holder

Geronimo Tapia

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