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Publication - Dr Rosalyn Moran

    Circadian dynamics in measures of cortical excitation and inhibition balance


    Chellappa, S, Meyer, C, Gaggioni, G, Ly, J, Rosanova, M, Simone, S, Archer, S, Luxen, A, Dijk, D-J, Massimini, M, Maquet, P, Phillips, C, Moran, R & Vandewalle, G, 2016, ‘Circadian dynamics in measures of cortical excitation and inhibition balance’. Scientific Reports, vol 6.


    Several neuropsychiatric and neurological disorders have recently been characterized as dysfunctions arising from a ‘final common pathway’ of imbalanced excitation to inhibition within cortical networks. How the regulation of a cortical E/I ratio is affected by sleep and the circadian rhythm however, remains to be established. Here we addressed this issue through the analyses of TMS-evoked responses recorded over a 29 h sleep deprivation protocol conducted in young and healthy volunteers. Spectral analyses of TMS-evoked responses in frontal cortex revealed non-linear changes in gamma band evoked oscillations, compatible with an influence of circadian timing on inhibitory interneuron activity. In silico inferences of cell-to-cell excitatory and inhibitory connectivity and GABA/Glutamate receptor time constant based on neural mass modeling within the Dynamic causal modeling framework, further suggested excitation/inhibition balance was under a strong circadian influence. These results indicate that circadian changes in EEG spectral properties, in measure of excitatory/inhibitory connectivity and in GABA/glutamate receptor function could support the maintenance of cognitive performance during a normal waking day, but also during overnight wakefulness. More generally, these findings demonstrate a slow daily regulation of cortical excitation/inhibition balance, which depends on circadian-timing and prior sleep-wake history.

    Full details in the University publications repository