Abstract

Many psychiatric illnesses first emerge very early in life, with clear behavioral risk markers detectable in infancy and early childhood. This early onset coincides with a period of rapid brain development and heightened plasticity, during which cortical architecture is still being actively shaped. To better understand the role of early brain development and psychiatric risk, it is first critical to understand how the brain is organized during this early postnatal period. The brain can be organized into cortical areas and large-scale functional networks, and these levels of organization can be identified in vivo in humans using resting-state functional connectivity (RSFC). In adults, RSFC studies reveal a broadly shared topology of cortical areas and networks across individuals, but also robust idiosyncratic variation in the precise topography, including the boundaries and spatial organization of these areas and networks. By contrast, cortical development in infants is still unfolding postnatally, and we know comparatively little about how cortical areas and functional networks are organized near birth or how much individual variability exists at this stage. This dissertation leverages group-level and individual-specific RSFC data from healthy neonates to establish a normative foundation of early postnatal functional brain organization and to characterize individual variability that may constitute early neural risk for psychopathology. This dissertation addresses this goal through three interrelated aims. Aim 1 defines shared organizational principles of neonatal cortical arealization by applying a boundary-mapping approach to group-averaged RSFC data from 261 neonates. This approach yielded a cortical area parcellation that captures robust local connectivity yet covers only about half the cortical surface after shrinking area parcels to their centers to improve external reliability. This need to shrink area parcels to their centers suggests either heterogeneous boundary locations across individuals or immature areal differentiation. To probe the individual variability of cortical area boundaries, aim 2 applies the same boundary-mapping approach within individuals in a neonatal precision dataset (n=8). These data demonstrate that large amounts of high-quality individual-specific RSFC data can delineate sharp cortical boundaries across much of the cortex, confirming both the feasibility of neonatal precision functional mapping and the presence of meaningful individual-specific areal topography near birth. Finally, aim 3 extends this characterization of functional brain organization in individual neonates to large-scale functional brain networks. These data reveal reliable, nascent adult-like network architectures whose topography varies across neonates. Additionally, these networks exhibit network-specific long-range FC selectivity, suggesting the early emergence of distributed network organization. Collectively, this dissertation provides the first integrated look at shared and individual-specific neonatal functional brain organization, laying the groundwork for mechanistic studies of how early deviations in functional architecture may contribute to psychiatric vulnerability.

Committee Chair

Chad Sylvester

Committee Members

Ashley Nielsen Preisser; Chris Smyser; Deanna Barch; Evan Gordon

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Neurosciences)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

6-24-2026

Language

English (en)

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Available for download on Friday, June 23, 2028

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