Brain waves could help predict how we respond to general anaesthetics
The complex pattern of ‘chatter’ between different areas of an individual’s brain while they are awake could help doctors better track and even predict their response to general anaesthesia – and better identify the amount of anaesthetic necessary – according to new research from the University of Cambridge.
Brain networks during the transition to unconsciousness during propofol sedation (drug infusion timeline shown in red). Participants with robust networks at baseline (left panel) remained resistant to the sedative, while others showed characteristically different, weaker networks during unconsciousness (middle). All participants regained similar networks when the sedative wore off (right).
As areas of the brain communicate with each other, they give off tell-tale signals that can give an indication of how conscious an individual is. These ‘networks’ of brain activity can be measured using an EEG. Cambridge researchers have previously shown that HYPERLINK “http://www.cam.ac.uk/research/news/scientists-find-hidden-brain-signatures-of-consciousness-in-vegetative-state-patients” these network signatures can even be seen in some people in a vegetative state and may help doctors identify patients who are aware despite being unable to communicate. These findings build upon advances in the science of networks to tackle the challenge of understanding and measuring human consciousness.
In a study published in PLoS Computational Biology, the researchers studied how these signals changed in healthy volunteers as they received an infusion of propofol.
Twenty individuals (9 male, 11 female) received a steadily increasing dose of propofol – all up to the same limit – while undergoing a task that involved pressing one button if they heard a ‘ping’ and a different button if they heard a ‘pong’. At the same time, the researchers tracked their brain network activity using an EEG.
By the time the subjects had reached the maximum dose, some individuals were still awake and able to carry out the task, while others were unconscious. As the researchers analysed the EEG readings, they found clear differences between those who were responding to the anaesthetic and those who remained able to carry on with the task. This ‘brain signature’ was evident in the network of communications between brain areas car