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

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ABSTRACT
During adolescence, the prefrontal cortex (PFC) undergoes significant maturation, supporting improvements in cognitive control and executive functions. Using 7T MRSI we have found greater PFC glutamatergic excitatory over inhibitory GABAergic function disturbing excitatory/inhibitory (E/I) balance indicative of critical period plasticity. To further confirm this finding and understand neural function mechanisms underlying this process, we now extend these findings applying EEG measures of E/I balance in the same participants. EEG broadband background aperiodic activity provides a unique measure of E/I balance using the Fitting Oscillations and 1/f (FOOOF) protocol, which derives the 1/f spectral slope (referred to as the aperiodic exponent) and an offset. Thus, we aim to provide in vivo validation of the underlying mechanisms of E/I balance in humans, via EEG and MRSI derived measures, and their associations with working memory development, supporting a period of PFC critical plasticity during adolescence. We hypothesized that MRSI measures of Glu/GABA balance would be associated with EEG aperiodic activity confirming recovery of E/I balance from adolescence to adulthood.