Propofol disrupts alpha dynamics in functionally distinct thalamocortical networks during loss of consciousness

What is it about?

Since the 1970s, general anesthesia using drugs like propofol has been known to cause a phenomenon called anteriorization, where brain rhythms shift from the posterior to the anterior. To date, the brain structures that produce anteriorization have been unknown. We used intracranial recordings from epilepsy patients to identify regions in sensory and prefrontal cortices where alpha activity is attenuated or amplified by propofol. Then, by performing diffusion tractography between these regions and the thalamus, we showed that rhythmic changes are linked to two distinct brain networks. Because these networks are associated with sensory and cognitive functions, respectively, propofol may interfere with these processes to cause loss of consciousness.

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Photo by Ibrahim Boran on Unsplash

Photo by Ibrahim Boran on Unsplash

Why is it important?

We establish for the first time a structure-function association between the thalamocortical networks of the brain and alpha rhythms observed during states of consciousness and general anesthesia. This finding, enabled by a large dataset of recordings from intracranially implanted electrodes in epilepsy patients as well as an open structural magnetic imaging dataset, offers insights into the effects of general anesthesia upon the multiple brain regions responsible for both sensory and cognitive functions during consciousness.