The Lights Are Out but Someone’s Home: Sensory Processing in Anaesthetized Human Brains

While patients lay unconscious under anesthesia, their brains kept decoding stories and preparing for what came next

Baylor College of Medicine researchers have found that the human brain is capable of sophisticated language processing while in an unconscious state from general anesthesia. The findings, published in Nature, challenge what we know about the role of consciousness and cognition, and could open new ways of understanding memory, language and brain-computer interfaces.

The brain processes overheard words under anesthesia, but it may not remember them

A study of people who underwent surgery to treat epilepsy suggests the hippocampus may process words and speech when people are under general anesthesia, even though the study participants didn’t remember them

The lights are out but someone’s home: sensory processing in anaesthetized human brains

Detailed neural recordings were made from a brain structure called the hippocampus in unconscious anaesthetized people. Neuronal activity responded to ‘oddballs’ in a series of auditory tones, encoded complex meaning-related properties of language and could even predict upcoming words in a heard phrase. Neurons in the hippocampuses of unconscious people undergoing brain surgery could predict upcoming words in a heard phrase.