Experimental plans. Issue 3

T3.1 Anaesthesia: (UOX, STA, IFADO, UMI): Apply the concepts/protocols employed during sleep stage N1 or dreaming to subjects who are in a state of mild sedation or during the induction of general anaesthesia (MOOAS level 3) in order to probe the capacity of tCS to (1) alter the EEG features of bistability and (2) shift the level of wakefulness. Explore the relationship of the SWAS biomarker within the information theoretic and PCI approach to consciousness state. We will gather ultra high field 7T resting state fMRI paradigms using the developed EEG metrics as end-points for titration of anaesthesia. In particular we will explore the functional thalamocortical connectivity of the sub-regions of thalamus at these EEG end-points, and identify changes in connectivity induced by tCS. Slow activity is a common feature of both sleep and anaesthesia. There is also evidence that some anaesthetics satisfy the homeostatic need for sleep (Pal2011). By using a within-subject design, we will explore the commonality of these mechanisms further by using EEG recordings of sleep prior to fMRI scanning. We will investigate the effect of tCS on the developed EEG consciousness metrics to elucidate whether the proposed brain interference methods will allow the required dose for anaesthesia-induced loss of consciousness to be reduced, thus reducing the known risks of over-anaesthesia.