Can a severed brain remain conscious?

"What would it feel like to be a brain in a vat? If you had no body and no world in which to ground yourself, could you be conscious of anything at all? Neuroscientists and philosophers have debated this thought experiment for decades as they have tried to understand how the three-pound organ in our heads can generate something as lofty as consciousness: an individual's feelings, thoughts and subjective sense of self."

"Your current conscious experience is likely dominated by the feeling of your body and the world around youthis is the case much of the time. But researchers like thinking about extreme cases to sharpen their theories about how consciousness works. So, they ask, can consciousness exist without these interactions with the outside world? Are they necessary in a deeper way? Are they necessary for any kind of consciousness at all? asks Anil Seth, a neuroscientist at the University of Sussex in England."

The brain-in-a-vat thought experiment questions whether consciousness requires bodily and environmental grounding. Conscious experience is often dominated by sensations of the body and the surrounding world, yet dreaming demonstrates a form of consciousness when sensory input is largely cut off. Researchers probe the necessity of bodily and external interactions by examining rare clinical cases such as hemispherotomy, a surgery that severs one cerebral hemisphere while maintaining its blood and nutrient supply. Studying isolated brain tissue and its experiential outcomes aims to reveal whether isolated neural systems can sustain conscious states and what forms those states might take.

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