Biology subjects

Hetherington, H.

Publications and source records attributed to Hetherington, H..

3 recordsLinked to original sources

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↗

bioRxiv2023

Aperiodic EEG and 7T MRSI evidence for maturation of E/I balance supporting the development of working memory through adolescence

Postmortem animal and human models suggest changes through adolescence in aspects of excitatory glutamatergic and inhibitory GABAergic function (E/I) in prefrontal cortex (PFC) suggestive of critical period plasticity at a time of significant cognitive development. Recently, using high field 7T Magnetic Resonance Spectroscopic Imaging (MRSI), we found in vivo evidence for increases in PFC glutamate/GABA balance through adolescence into adulthood. We now extend these MRSI findings by investigating, in the same 164 10- 32-year-old participants, its correspondence with EEG aperiodic activity, an independent measure of E/I balance elucidating changes in neural activity. Results showed decreases in PFC aperiodic activity from adolescence to adulthood, that were associated with MRSI measures of glutamate/GABA balance as well as mediating the association between age and EEG aperiodic activity. Further, changes in aperiodic activity predicted performance on a working memory task, indicating a role for E/I based changes in PFC signaling mechanisms in supporting maturation of cognitive control. Taken together, these results suggest that PFC is undergoing critical period plasticity through adolescence evident in both neurotransmitter and neural function that supports cognitive development.

neuroscience↗

bioRxiv2022

Changes in prefrontal GABA and glutamate through adolescence supports excitation/inhibition balance

Animal and human postmortem studies provide evidence for changes in gamma-aminobutyric acid (GABA) and glutamate in prefrontal cortex (PFC) during adolescence, suggesting shifts in excitation and inhibition balance consistent with critical period plasticity. However, how GABA and glutamate change through adolescence and how the balance of these inhibitory and excitatory neurotransmitters changes is not well understood in vivo in humans. High field (7 Tesla) Magnetic Resonance Spectroscopic Imaging was used to investigate age-related changes in the balance of GABA/creatine (Cr) and glutamate/Cr in multiple developmentally-relevant regions of PFC in 144 10 to 30-year-olds. Results indicated a homogenous pattern of age-related Glu/Cr decreases across PFC regions, while age-related changes in GABA/Cr were heterogenous, with a mix of stable and decreasing age effects. Importantly, balance between glutamate/Cr and GABA/Cr in areas of prefrontal cortex increased through adolescence, suggesting the presence of critical period plasticity in PFC at this significant time of development when adult trajectories are established.

neuroscience↗