July 5, 2022

CONTROVERSY OVER BRAIN-DEAD PATIENT

Back in September, British researchers startled the neuroscience world when they reported in Science that a severely brain-damaged and apparently unresponsive patient had responded to instructions. A scan of her brain was indistinguishable from scans of healthy volunteers when she was asked to imagine playing tennis or walking through her house. The implication was that at least some patients in a “permanent vegetative state” may actually be conscious.

The unsettling experiment has now been criticised by other scientists. Two letters in Science observe that the words “tennis” and “house” might have elicited automatic responses in the brain. However, the original researchers still insist that their patient was “consciously aware”. Had the response been automatic, they argue, there would only have been a flicker in the word processing region of the brain. But what they observed was a sustained response in regions of the brain which are involved in “purposefully imagining coordinated movements” and “real or imagined spatial navigation”. The simplest explanation of their data, they conclude, is that the patient was truly consciously aware.