Local wakefulness-like activity of layer 5 cortex under general anaesthesia.
The Journal of Physiology October 1, 2024 Jesús Pardo-Valencia, Miryam Moreno-Gomez, Noelia Mercado et al.
Under isoflurane anaesthesia, activating layer 5 pyramidal neurons in one hemisphere of the mouse sensorimotor cortex using chemogenetics (DREADDs) produced local wakefulness-like activity—shifting from slow-wave to tonic firing—and disrupted interhemispheric synchrony with the opposite hemisphere. However, this local activation did not reduce the depth of unconsciousness during deep anaesthesia or during transitions into or out of anaesthesia. Global layer 5 synchrony may be sufficient for anaesthesia-induced unconsciousness but is not necessary, at least under isoflurane. Local wakefulness-like activity in layer 5 cortex can occur during deep anaesthesia, highlighting the need to further explore local versus global aspects of anaesthesia-induced unconsciousness.