Investigating the different roles of interneuronal populations in modulating cortical dynamics (360G-Wellcome-099755_Z_12_A)

Normal and pathological brain activity is characterised by changes in brain rhythms. Such changes are linked to attention, sleep-wake cycles, or epilepticseizures. During an epileptic seizure, for example, there are a series of transitions which are often highly stereotyped in individuals, and which may be pathognomonic of the seizure type. There are various animal and computational models for generating oscillations in specific frequency bands. However, the transition between frequencies is not well understood. Cortical layers might show distinct frequencies that interact and lead to altered frequencies in following time steps. Furthermore, input from thalamus, corpus callosum or adjacent cortical areas might trigger frequency transitions. This project will use optogenetics to change input and on-going activity in specific circuits to test their influence on frequency transitions. Experiments will be complemented by computational models of cortical circuits to better understand on-going dynamics and inform the selection of future targets for experimental stimulation. This work will not only be important in assessing transitions in epilepsy (e.g. from the inter-ictal to the ictal stage), but also for models of external interventions to change pathological brain rhythms in the future.