title: Laminar analysis of the slow wave activity in the somatosensory cortex of anesthetized rats.
abstract: Rhythmic slow waves characterize brain electrical activity during natural deep sleep and under anesthesia, reflecting the synchronous membrane potential fluctuations of neurons in the thalamocortical network. Strong evidence indicates that the neocortex plays an important role in the generation of slow wave activity (SWA), however, contributions of individual cortical layers to the SWA generation are still unclear. The anatomically correct laminar profiles of SWA were revealed under ketamine/xylazine anesthesia, with combined local field potential recordings, multiple-unit activity (MUA), current source density (CSD) and time-frequency analyses precisely co-registered with histology. The up-state related negative field potential wave showed the largest amplitude in layer IV, the CSD was largest in layers I and III, whereas MUA was maximal in layer V, suggesting spatially dissociated firing and synaptic/transmembrane processes in the rat somatosensory cortex. Up-state related firing could start in virtually any layers (III-VI) of the cortex, but were most frequently initiated in layer V. However, in a subset of experiments, layer IV was considerably active in initiating up-state related MUA even in the absence of somatosensory stimulation. Somatosensory stimulation further strengthened up-state initiation in layer IV. Our results confirm that cortical layer V firing may have a major contribution to the up-state generation of ketamine/xylazine-induced SWA, however, thalamic influence through the thalamorecipient layer IV can also play an initiating role, even in the absence of sensory stimulation.
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.|School of Ph.D. Studies, Semmelweis University, Budapest, Hungary.|Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: Richárd
authors.initials: R
authors.lastname: Fiáth
authors.affiliation: Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: Bálint Péter
authors.identifier: 0000-0001-9542-8082
authors.initials: BP
authors.lastname: Kerekes
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
authors.forename: Lucia
authors.identifier: 0000-0001-6800-0953
authors.initials: L
authors.lastname: Wittner
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
authors.forename: Kinga
authors.identifier: 0000-0002-8751-8499
authors.initials: K
authors.lastname: Tóth
authors.affiliation: Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Beregszászi
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.|School of Ph.D. Studies, Semmelweis University, Budapest, Hungary.|Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: Domonkos
authors.identifier: 0000-0001-7310-2890
authors.initials: D
authors.lastname: Horváth
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.|Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: István
authors.identifier: 0000-0001-9941-9159
authors.initials: I
authors.lastname: Ulbert
mesh_terms: D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D058256:Brain Waves; D005073:Evoked Potentials, Somatosensory; D005260:Female; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology*; D014991:Xylazine / Q000494:pharmacology
chemical_list: D000700:Analgesics; D014991:Xylazine; D007649:Ketamine
keywords: current source density analysis; local field potential; multiple-unit activity; slow (< 1 Hz) oscillation; slow wave activity