Graduation Date

Spring 5-4-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Interdisciplinary Graduate Program in Biomedical Sciences

First Advisor

Tony Wilson, PhD

Second Advisor

Soonjo Hwang, PhD

Third Advisor

Elizabeth Heinrichs-Graham, PhD

Fourth Advisor

Jennifer Blackford, PhD

Abstract

During the sensitive period of adolescence, the human brain undergoes dynamic changes in structure and function resulting in vast executive function gains. Verbal working memory (VWM) is one executive function that serves as a foundation to language acquisition, reading, and learning. Many have examined the development of VWM in youth, but few have probed age-related changes in the underlying neural oscillatory dynamics, and none have examined testosterone-related changes. We recorded magnetoencephalography during a modified Sternberg VWM task in 82 youth participants aged 6 – 14 years old and collected salivary testosterone samples. Significant oscillatory responses were identified and imaged using a beamforming approach and the resulting whole-brain maps were probed for developmental effects during the encoding and maintenance phases. First, we identified cortical regions in which oscillatory power significantly covaried with chronological age (Chapter 1), and then we quantified the functional connectivity between these regions, using phase-locking value, as a function of chronological age (Chapter 2). Lastly, we probed whole-brain maps for cortical regions exhibiting significant relationships between oscillatory power and endogenous testosterone hormone levels, controlling for age (Chapter 3). These results extend the existing literature on working memory development by showing strong associations between oscillatory dynamics and unique development measures across a distributed network.

Comments

2024 Copyright, the authors

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