Biomedical Sciences ETDs

Publication Date

Spring 5-2026

Abstract

Behavioral flexibility—the ability to adapt behavior when contingencies change—is a fundamental executive function supported by orbitofrontal–striatal circuitry. This dissertation examined molecular, motivational, and circuit mechanisms underlying flexibility and its restoration after prenatal alcohol exposure (PAE). In healthy mice, GluN2B-containing NMDA receptors in the orbitofrontal cortex increased during outcome updating, while AMPA receptor subunits in the dorsal striatum rose during new learning, defining temporally distinct plasticity processes. PAE impaired reversal learning under low-reward conditions, but not when motivation was high, indicating altered thresholds for circuit engagement rather than permanent loss. Finally, optogenetic stimulation of OFC→dorsal striatum projections rescued flexibility in PAE mice, revealing preserved but under-recruited circuitry. Together, these studies identify dynamic glutamatergic mechanisms that support adaptive learning, demonstrate how motivation gates cognitive expression of developmental insult, and show that circuit activation can restore flexibility, highlighting latent neural resilience.

Keywords

behavioral flexibility, prenatal alcohol exposure, optogenetic rescue, orbitofrontal–striatal circuitry, glutamatergic receptor dynamics, reversal learning

Document Type

Dissertation

Language

English

Degree Name

Biomedical Sciences

Level of Degree

Doctoral

Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

Jonathan L. Brigman

Second Committee Member

Carlos Fernando Valenzuela

Third Committee Member

Nora Perrone Bizzozero

Fourth Committee Member

Erin Milligan

Fifth Committee Member

David Linsenbardt

Sixth Committee Member

Derek Hamilton

Comments

Behavioral flexibility—the ability to adapt behavior when contingencies change—is a fundamental executive function supported by orbitofrontal–striatal circuitry. This dissertation examined molecular, motivational, and circuit mechanisms underlying flexibility and its restoration after prenatal alcohol exposure (PAE). In healthy mice, GluN2B-containing NMDA receptors in the orbitofrontal cortex increased during outcome updating, while AMPA receptor subunits in the dorsal striatum rose during new learning, defining temporally distinct plasticity processes. PAE impaired reversal learning under low-reward conditions, but not when motivation was high, indicating altered thresholds for circuit engagement rather than permanent loss. Finally, optogenetic stimulation of OFC→dorsal striatum projections rescued flexibility in PAE mice, revealing preserved but under-recruited circuitry. Together, these studies identify dynamic glutamatergic mechanisms that support adaptive learning, demonstrate how motivation gates cognitive expression of developmental insult, and show that circuit activation can restore flexibility, highlighting latent neural resilience.

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