--- _id: '3515' abstract: - lang: eng text: Oscillations in neuronal networks are assumed to serve various physiological functions, from coordination of motor patterns to perceptual binding of sensory information. Here, we describe an ultra-slow oscillation (0.025 Hz) in the hippocampus. Extracellular and intracellular activity was recorded from the CA1 and subicular regions in rats of the Wistar and Sprague-Dawley strains. anesthetized with urethane. in a subgroup of Wistar rats (23%), spontaneous afterdischarges (4.7 +/- 1.6 s) occurred regularly at 40.8 +/- 15.7 s. The afterdischarge was initiated by a fast increase of population synchrony (100-250 Hz oscillation; “tonic” phase), followed by large-amplitude rhythmic waves and associated action potentials at gamma and beta frequency (15-50 Hz; “clonic” phase). The afterdischarges were bilaterally synchronous and terminated relatively abruptly without post-ictal depression. Single-pulse stimulation of the commissural input could trigger afterdischarges, but only at times when they were about to occur. Commissural stimulation evoked inhibitory postsynaptic potentials in pyramidal cells. However, when the stimulus triggered an afterdischarge, the inhibitory postsynaptic potential was absent and the cells remained depolarized during most of the afterdischarge. Afterdischarges were not observed in the Sprague-Dawley rats. Long-term analysis of interneuronal activity in intact, drug-free rats also revealed periodic excitability changes in the hippocampal network at 0.025 Hz. These findings indicate the presence of an ultra-slow oscillation in the hippocampal formation. The ultra-slow clock induced afterdischarges in susceptible animals. We hypothesize that a transient failure of GABAergic inhibition in a subset of Wistar rats is responsible for the emergence of epileptiform patterns. (C) 1999 IBRO. Published by Elsevier Science Ltd. acknowledgement: This work was supported by the Academy of Finland (32391) and the NIH (NS34994, MH54671). article_processing_charge: No article_type: original author: - first_name: Markku full_name: Penttonen, Markku last_name: Penttonen - first_name: Nina full_name: Nurminen, Nina last_name: Nurminen - first_name: Riitta full_name: Miettinen, Riitta last_name: Miettinen - first_name: Jouni full_name: Sirviö, Jouni last_name: Sirviö - first_name: Darrell full_name: Henze, Darrell last_name: Henze - first_name: Jozsef L full_name: Csicsvari, Jozsef L id: 3FA14672-F248-11E8-B48F-1D18A9856A87 last_name: Csicsvari orcid: 0000-0002-5193-4036 - first_name: György full_name: Buzsáki, György last_name: Buzsáki citation: ama: Penttonen M, Nurminen N, Miettinen R, et al. Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats. Neuroscience. 1999;94(3):735-743. doi:10.1016/S0306-4522(99)00367-X apa: Penttonen, M., Nurminen, N., Miettinen, R., Sirviö, J., Henze, D., Csicsvari, J. L., & Buzsáki, G. (1999). Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats. Neuroscience. Elsevier. https://doi.org/10.1016/S0306-4522(99)00367-X chicago: Penttonen, Markku, Nina Nurminen, Riitta Miettinen, Jouni Sirviö, Darrell Henze, Jozsef L Csicsvari, and György Buzsáki. “Ultra-Slow Oscillation (0.025 Hz) Triggers Hippocampal Afterdischarges in Wistar Rats.” Neuroscience. Elsevier, 1999. https://doi.org/10.1016/S0306-4522(99)00367-X. ieee: M. Penttonen et al., “Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats,” Neuroscience, vol. 94, no. 3. Elsevier, pp. 735–743, 1999. ista: Penttonen M, Nurminen N, Miettinen R, Sirviö J, Henze D, Csicsvari JL, Buzsáki G. 1999. Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats. Neuroscience. 94(3), 735–743. mla: Penttonen, Markku, et al. “Ultra-Slow Oscillation (0.025 Hz) Triggers Hippocampal Afterdischarges in Wistar Rats.” Neuroscience, vol. 94, no. 3, Elsevier, 1999, pp. 735–43, doi:10.1016/S0306-4522(99)00367-X. short: M. Penttonen, N. Nurminen, R. Miettinen, J. Sirviö, D. Henze, J.L. Csicsvari, G. Buzsáki, Neuroscience 94 (1999) 735–743. date_created: 2018-12-11T12:03:44Z date_published: 1999-10-01T00:00:00Z date_updated: 2022-09-07T13:16:01Z day: '01' doi: 10.1016/S0306-4522(99)00367-X extern: '1' external_id: pmid: - '10579564' intvolume: ' 94' issue: '3' language: - iso: eng month: '10' oa_version: None page: 735 - 743 pmid: 1 publication: Neuroscience publication_identifier: issn: - 0306-4522 publication_status: published publisher: Elsevier publist_id: '2870' quality_controlled: '1' scopus_import: '1' status: public title: Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats type: journal_article user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17 volume: 94 year: '1999' ...