Biology subjects

McKeon, S. D.

Publications and source records attributed to McKeon, S. D..

4 recordsLinked to original sources

bioRxiv2026

Developmental interactions between oscillatory and spontaneous neural activity support improvements in inhibitory control from adolescence into adulthood

Adolescence is a critical period of development marked by improvements in cognitive control driven by maturation of executive brain systems. Neural mechanisms supporting inhibitory control (the ability to suppress a prepotent response in favor of generating a goal-directed response) mature into adulthood in parallel with refinements in frequency-specific neural oscillations and broadband spontaneous activity, supporting more accurate and reliable performance on response inhibition tasks, such as the antisaccade oculomotor task. Prior work has established that the maturation of neural circuitry contributes to age-related decreases in spontaneous activity, supporting higher-fidelity transmission of task-relevant activity, such as frequency-specific neural oscillations, which are crucial for antisaccade performance. Using longitudinal electroencephalography (EEG) data from 146 participants (72 F, ages 10-34, 253 total sessions) collected while participants performed an antisaccade task, we sought to understand the interplay between frontal oscillatory and spontaneous activity during cognitive processing and how it supports developmental improvements in inhibitory control. We found that spontaneous activity decreased developmentally during the preparation of an inhibitory response, and that this was associated with reduced trial-to-trial variability in response latency, indicating that reductions in spontaneous activity may increase the reliability of inhibitory control processing. Furthermore, performance-related decreases in broadband spontaneous activity were associated with the suppression of preparatory high-beta oscillations in an age-dependent manner, such that this relationship became more pronounced through development. Together, these results illustrate how developmental enhancements in the coordination of frequency-specific oscillations and spontaneous activity during inhibitory response preparation support developmental improvements in inhibitory control, providing a potential mechanism through which inhibitory control becomes more accurate and reliable from adolescence into adulthood.

neuroscience↗

bioRxiv2025

Cross-species evidence for the refinement of intrinsic neural timescales supporting executive system maturation through adolescence

Brain functional, structural, and neurochemical maturation has been found to support the specialization of executive systems through adolescence that will lead to adult level processing. Importantly, animal models and initial EEG studies in humans indicate developmental improvements in neural processing of complex information that would be evident in changes in temporal dynamics, which are not well-understood. Intrinsic neural timescales (INTs), or the temporal windows over which neural populations integrate inputs, have been proposed to reflect circuit-level properties such as excitatory-inhibitory (E/I) balance, myelination, and functional properties supporting complex information processing such as in executive functioning. Here, we used a multimodal, cross-species approach to investigate how INTs develop across adolescence to support cognitive specialization. In parallel analyses using a large longitudinal human EEG cohort, adolescent intracranial sEEG recordings, and macaque local field potentials, we observed robust reductions in INTs through adolescence, particularly in frontal and parietal association cortices. These developmental reductions were shaped by local circuit physiology, as evidenced by associations between shorter INTs and both lower aperiodic exponents, indicative of increased E/I balance, and reduced spectral offsets, suggesting lower aggregate spiking. We also found structural contributions via developmental interactions between age and deep layer intracortical myelination which predicted shorter INTs, suggesting that long-range circuitry may play a key role in shaping spontaneous temporal dynamics. Functionally, shorter INTs in adolescence were linked to improved working memory accuracy and reduced response time variability, indicating a behavioral advantage of refined temporal integration windows through development. Together, these findings establish INTs as a conserved, biologically grounded signature of adolescent brain maturation, providing a mechanistic framework for how structural and physiological refinements reorganize temporal processing to support increasingly efficient cognitive function.

neuroscience↗

bioRxiv2025

Heterochronous laminar maturation in the human prefrontal cortex

The human prefrontal cortex (PFC) exhibits markedly protracted developmental plasticity, yet whether reductions in plasticity occur synchronously across prefrontal cortical layers is unclear. Animal studies have shown that intracortical myelin consolidates developing circuits by restricting ongoing neuronal plasticity. Here, we use longitudinal myelin-sensitive imaging collected at ultra-high field to investigate whether superficial and deep PFC layers exhibit different timeframes of malleability. We find that myelin matures earlier in deep than in superficial compartments of the cortical ribbon; this laminar divergence in maturational timing is differentially expressed across cytoarchitecturally and functionally distinct frontal regions. By integrating myelin mapping with EEG and behavioral phenotyping, we provide evidence that prefrontal myelin impacts timescales of neural activity, task learning rates, and cognitive processing speed. Heterochronous myelination across deep and superficial layers is an underrecognized mechanism through which human association cortex balances cognitively-relevant increases in circuit stability and efficiency with extended neuroplasticity.

neuroscience↗

bioRxiv2024

Prefrontal Excitation/ Inhibition Balance Supports Adolescent Enhancements in Circuit Signal to Noise Ratio

The development and refinement of neuronal circuitry allow for stabilized and efficient neural recruitment, supporting adult-like behavioral performance. During adolescence, the maturation of PFC is proposed to be a critical period (CP) for executive function, driven by a break in balance between glutamatergic excitation and GABAergic inhibition (E/I) neurotransmission. During CPs, cortical circuitry fine-tunes to improve information processing and reliable responses to stimuli, shifting from spontaneous to evoked activity, enhancing the SNR, and promoting neural synchronization. Harnessing 7T MR spectroscopy and EEG in a longitudinal cohort (N = 164, ages 10-32 years, 283 neuroimaging sessions), we outline associations between age-related changes in glutamate and GABA neurotransmitters and EEG measures of cortical SNR. We find developmental decreases in spontaneous activity and increases in cortical SNR during our auditory steady state task using 40 Hz stimuli. Decreases in spontaneous activity were associated with glutamate levels in DLPFC, while increases in cortical SNR were associated with more balanced Glu and GABA levels. These changes were associated with improvements in working memory performance. This study provides evidence of CP plasticity in the human PFC during adolescence, leading to stabilized circuitry that allows for the optimal recruitment and integration of multisensory input, resulting in improved executive function.

neuroscience↗