Author Type

Graduate Student

Date of Award

Fall 9-12-2025

Document Type

Thesis

Publication Status

Version of Record

Submission Date

November 2025

Department

Biological Sciences

Degree Name

Master of Science (MS)

Thesis/Dissertation Advisor [Chair]

Erik Duboué

Abstract

The topology of the brain is highly conserved across phyla, yet the evolutionary processes driving anatomical divergence remain poorly understood. The fish Astyanax mexicanus, which exists in both surface- and cave-dwelling morphs within the same species, provides a powerful model for studying brain evolution. While previous studies have focused on larvae, imaging adult brains has been challenging due to their size and opacity. This study overcame these limitations using tissue clearing, light sheet imaging, and computational analysis to generate a comprehensive adult brain atlas. Using nuclear staining and antibody labeling, brain-wide 3D maps were created to compare regional size, shape, and molecular identity across surface fish, cavefish, and F2 hybrids. In parallel, behaviorally induced neuronal activity was mapped using pS6 immunolabeling following a stress-based novel tank diving assay. These findings reveal how genetic and environmental factors shape adult brain structure and activity, offering new insights into the evolution of neuroanatomy and behavior.

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