Publication Highlight
Ketamine anaesthesia induces gain enhancement via recurrent excitation in granular input layers of the auditory cortex
Katrina E. Deane, Michael G. K. Brunk, Andrew W. Curran, Marina M. Zempeltzi, Jing Ma, Xiao Lin, Francesca Abela, Sümeyra Aksit, Matthias Deliano, Frank W. Ohl, Max F. K. Happel
Key points
Ketamine is a common anaesthetic agent used in research and more recently as medication in treatment of depression. It has known effects on inhibition of interneurons and cortical stimulus‐locked responses, but the underlying functional network mechanisms are still elusive.
Analysing population activity across all layers within the auditory cortex, we found that doses of this anaesthetic induce a stronger activation and stimulus‐locked response to pure‐tone stimuli.
This cortical response is driven by gain enhancement of thalamocortical input processing selectively within granular layers due to an increased recurrent excitation.
Time–frequency analysis indicates a higher broadband magnitude response and prolonged phase coherence in granular layers, possibly pointing to disinhibition of this recurrent excitation.
These results further the understanding of ketamine's functional mechanisms, which will improve the ability to interpret physiological studies moving from anaesthetized to awake paradigms and may lead to the development of better ketamine‐based depression treatments with lower side effects.
