A new study shows that 42 really is the answer to life, the universe, and everything. OK, not really, but it does show that 42% of healthy brain activity is the minimum threshold for consciousness.
Disorders of consciousness, also referred to as coma when severe enough, can be a difficult situation to assess sufficiently to make reliable predictions about outcome. Part of the problem is that once someone is not able to maintain consciousness, we lose much of the neurological exam, and therefore it becomes more difficult to assess brain function other than to say that they are not conscious.
Types of coma
Two types of coma in particular are of interest: the persistent vegetative state, also called unresponsive wakefulness syndrome (UWS), and the minimally conscious state (MCS). Both are severe impairments of consciousness. In UWS, by definition, the patient may have sleep-wake cycles, open their eye, have roving eye movements, and grimace, but they do not have any interaction with their environment. They do not respond to voice, look at faces, or move in response to stimuli.
In his first book, On Being Certain: Believing You Are Right Even When You’re Wrong, neurologist Robert Burton showed that our certainty that we are right has nothing to do with how right we are. He explained how brain mechanisms can make us feel even more confident about false beliefs than about true ones. Now, in a new book, A Skeptic’s Guide to the Mind: What Neuroscience Can and Cannot Tell Us About Ourselves, he investigates the larger question of how a brain creates a mind. There is no alternative to the scientific method for studying the physical world, but Burton thinks there are essential limitations to science’s ability to investigate conundrums like consciousness and free will. Brain scientists fall into error because:
…our brains possess involuntary mechanisms that make unbiased thought impossible yet create the illusion that we are rational creatures capable of fully understanding the mind created by these same mechanisms.
He has a bone to pick with neuroscientists. They are discovering fascinating information, but their interpretations often go beyond what the data can really tell us. They often draw questionable conclusions from imaging studies that could have other explanations. (more…)