event
Tuesday 01 Dec 2020: Loss of consciousness in general anaesthesia may be understood by de-noising the brain
Axel Hutt - INRIA Grand Est
https://Universityofexeter.zoom.us/j/95563034432?pwd=d2U5cWN4U1JtZlIvLytyMTkrNExyZz09 Meeting ID: 955 6303 4432 Password: 883575 13:30-14:30
The physiological mechanisms by which anaesthetic drugs modulate oscillatory brain activity remain poorly understood. Combining human data, mathematical and computational analysis of both spiking and mean-field models, we investigated the spectral dynamics of encephalographic (EEG) beta-alpha oscillations, observed in human patients undergoing general anaesthesia. Based on previous own mathematical studies, we have assumed that additive random fluctuations may change the nonlinear interaction between neutrons yielding to new dynamic states. To this end, we modelled the effect of anaesthetics as a reduction of neural fluctuation intensity, and/or an increase in inhibitory synaptic gain in the thalamo-cortical circuit. Our analysis demonstrates that a non-linear transition, triggered by a simple decrease in neural fluctuation intensity, is sufficient to explain the clinically-observed appearance – and subsequent slowing – of the beta-alpha narrowband EEG peak. Taken together, our results show that such a non-linear transition results in functional fragmentation of cortical and thalamic populations; highly correlated intra-population dynamics triggered by anaesthesia decouple and isolate neural populations.
