TY - JOUR A1 - Deane, Katrina E. A1 - Brunk, Michael G. K. A1 - Curran, Andrew W. A1 - Zempeltzi, Marina M. A1 - Ma, Jing A1 - Lin, Xiao A1 - Abela, Francesca A1 - Aksit, Sümeyra A1 - Deliano, Matthias A1 - Ohl, Frank W. A1 - Happel, Max F. K. T1 - Ketamine anaesthesia induces gain enhancement via recurrent excitation in granular input layers of the auditory cortex T2 - The Journal of Physiology N2 - Ketamine is commonly used as an anaesthetic agent and has more recently gained attention as an antidepressant. It has been linked to increased stimulus‐locked excitability, inhibition of interneurons and modulation of intrinsic neuronal oscillations. However, the functional network mechanisms are still elusive. A better understanding of these anaesthetic network effects may improve upon previous interpretations of seminal studies conducted under anaesthesia and have widespread relevance for neuroscience with awake and anaesthetized subjects as well as in medicine. Here, we investigated the effects of anaesthetic doses of ketamine (15 mg kg\(^{-1}\) h\(^{-1}\)i.p.) on the network activity after pure‐tone stimulation within the auditory cortex of male Mongolian gerbils (Meriones unguiculatus). We used laminar current source density (CSD) analysis and subsequent layer‐specific continuous wavelet analysis to investigate spatiotemporal response dynamics on cortical columnar processing in awake and ketamine‐anaesthetized animals. We found thalamocortical input processing within granular layers III/IV to be significantly increased under ketamine. This layer‐dependent gain enhancement under ketamine was not due to changes in cross‐trial phase coherence but was rather attributed to a broadband increase in magnitude reflecting an increase in recurrent excitation. A time–frequency analysis was indicative of a prolonged period of stimulus‐induced excitation possibly due to a reduced coupling of excitation and inhibition in granular input circuits – in line with the common hypothesis of cortical disinhibition via suppression of GABAergic interneurons. KW - auditory cortex KW - continuous wavelet analysis KW - current source density KW - ketamine anaesthesia KW - laminar recording KW - mesoscopic KW - microcircuitry KW - population dynamics Y1 - 2020 UR - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/21612 UR - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-216123 VL - 598 IS - 13 SP - 2741 EP - 2755 ER -