A new study reveals that the brain may continue interpreting language and predicting information even while unconscious under anesthesia.
Researchers at Baylor College of Medicine have discovered that the human brain can continue carrying out complex language processing even while a person is unconscious under general anesthesia. The study, published in Nature, challenges long-standing ideas about consciousness and cognition and may lead to new insights into memory, language, and brain-computer interfaces.
“Our findings show that the brain is far more active and capable during unconsciousness than previously thought,” said Dr. Sameer Sheth, professor and Cullen Foundation Endowed chair of neurosurgery and a McNair Scholar at Baylor. “Even when patients are fully anesthetized, their brains continue to analyze the world around them.”
During epilepsy surgeries, Sheth and his colleagues recorded activity from hundreds of individual neurons in the hippocampus, a brain region linked to memory. These procedures gave researchers rare access to this deep part of the brain while patients were under general anesthesia.
Neuropixels Probes Reveal Learning During Unconsciousness
Using Neuropixels probes, which had never before been used in this area of the brain, the researchers measured how the hippocampus responded to sound and language without conscious awareness.
In the first experiment, patients listened to repeated tones that were occasionally interrupted by a different sound. The team found that hippocampal neurons could identify the unusual tones, and their responses became stronger over time. This suggests the brain may still undergo learning or neural plasticity during anesthesia.
The researchers then carried out a more advanced test by playing short stories while tracking neural activity. The hippocampus appeared to process language in real time. Patterns of neuron firing showed that the brain could distinguish between parts of speech such as nouns, verbs, and adjectives.
Predictive Language Processing Without Conscious Awareness
The researchers also found evidence that the brain could predict upcoming words in a sentence.
“The brain appears to anticipate what comes next in a story, even without conscious awareness,” said Sheth, who is also Director of The Gordon and Mary Cain Pediatric Neurology Research Foundation Laboratories within the Duncan Neurological Research Institute at Texas Children’s Hospital.
“This kind of predictive coding is something we associate with being awake and attentive, yet it’s happening here in an unconscious state,” said Dr. Benjamin Hayden, professor of neurosurgery at Baylor.
The findings suggest that abilities such as language comprehension and prediction may not require consciousness itself. Instead, consciousness could depend on wider coordination between multiple brain regions rather than activity limited to the hippocampus.
AI Comparisons and Future Speech Prosthetics
The brain activity observed in the study also resembles processes used in artificial intelligence (AI). The brain’s ability to anticipate upcoming words is similar to how large language models generate text. Researchers say these results may improve understanding of how both biological and artificial systems handle information.
The work could also support future communication technologies, including speech prosthetics designed for people who cannot speak.
“Can we use these signals to deploy and run a speech prosthetic for some of the parts of the brain that are damaged by stroke or injury? These are questions that we can now consider in relation to this part of the brain,” said Dr. Vigi Katlowitz, first author and a neurosurgery resident with Baylor.
Researchers Say Questions About Consciousness Remain Unanswered
The researchers caution that more studies are needed. The results only apply to one form of anesthesia and may not extend to other unconscious states such as sleep or coma. The study also focused on a single brain region, so scientists do not yet know how widespread these processes are throughout the brain.
“This work pushes us to rethink what it means to be conscious,” said Sheth. “The brain is doing much more behind the scenes than we fully understand.”
Reference: “Plasticity and language in the anaesthetized human hippocampus” by Kalman A. Katlowitz, Eric R. Cole, Elizabeth A. Mickiewicz, Shraddha Shah, Melissa Franch, Joshua A. Adkinson, James L. Belanger, Raissa K. Mathura, Domokos Meszéna, Matthew McGinley, William Muñoz, Garrett P. Banks, Sydney S. Cash, Chih-Wei Hsu, Angelique C. Paulk, Nicole R. Provenza, Andrew J. Watrous, Ziv Williams, Alica M. Goldman, Vaishnav Krishnan, Atul Maheshwari, Sarah R. Heilbronner, Robert Kim, Nuttida Rungratsameetaweemana, Benjamin Y. Hayden and Sameer A. Sheth, 6 May 2026, Nature.
DOI: 10.1038/s41586-026-10448-0
This project was funded in part by the National Institutes of Health (U01 NS121472), the McNair Foundation and the Gordon and Mary Cain Pediatric Neurology Research Foundation. This project was supported by the Optical Imaging & Vital Microscopy Core at the Baylor College of Medicine and by the McNair Foundation.
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