Unconsciousness is characterized by an inability to report subjective experience. For patients under anaesthesia, or in a more enduring state of unconsciousness caused by brain injury, reliable markers that indicate the presence or absence of consciousness remain elusive. Now, an international team of scientists has reported functional MRI (fMRI)-based evidence of distinct patterns of brain activity that could differentiate consciousness from unconsciousness (Sci. Adv. 10.1126/sciadv.aat7603).
To search for these indicators, Athena Demertzi and colleagues recorded fMRI data from 159 subjects scanned at four independent research sites. Participants included healthy individuals, as well as patients diagnosed with unresponsive wakefulness syndrome (UWS), in which they can open their eyes but do not display voluntary movements, and patients in a minimally conscious state (MCS), in which they show additional behaviours potentially indicative of awareness.