Australasian Science: Australia's authority on science since 1938

Rebooting the Brain

By Tim Hannan

A study of recovery from anaesthesia finds that returning to consciousness is not a simple path.

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One of the enduring mysteries of the human brain is how it transitions between the conscious and unconscious states. It is not well-understood how the brain, when recovering from a major disruption to its activity, is able to navigate its way back to consciousness.

Anaesthesia has been the most useful method of studying this process, and past observation of patients undergoing surgery has led to the popular intuition that, as the anaesthetic wears off, the brain simply wakes gradually, much like an energy-saving light bulb steadily increasing illumination over time. However, a new study has found that this theory is incorrect, and that the anaesthetised brain moves through a series of stable, discrete states en route to consciousness, in a manner more analogous to a computer being rebooted.

Anaesthesia is the practice of inducing unconsciousness, a state in which a person is neither awake nor aware. In this state, pain and other unpleasant sensations are not experienced, so an individual may undergo surgical or other medical procedures without distress or discomfort.

Of course, the brain is not completely inactive while anaesthetised, as neurons continue to generate electrical activity, which can be monitored in various regions as a local field potential. The nature of this low-level brain activity is not well-understood, and neither is the process...

The full text of this article can be purchased from Informit.