title: Pyramidal neurons in the superficial layers of rat retrosplenial cortex exhibit a late-spiking firing property.
abstract: The rodent granular retrosplenial cortex (GRS) is reciprocally connected with the hippocampus. It is part of several networks implicated in spatial learning and memory, and is known to contain head-direction cells. There are, however, few specifics concerning the mechanisms and microcircuitry underlying its involvement in spatial and mnemonic functions. In this report, we set out to characterize intrinsic properties of a distinctive population of small pyramidal neurons in layer 2 of rat GRS. These neurons, as well as those in adjoining layer 3, were found to exhibit a late-spiking (LS) firing property. We established by multiple criteria that the LS property is a consequence of delayed rectifier and A-type potassium channels. These were identified as Kv1.1, Kv1.4 and Kv4.3 by Genechip analysis, in situ hybridization, single-cell reverse transcriptase-polymerase chain reaction, and pharmacological blockade. The LS property might facilitate comparison or integration of synaptic inputs during an interval delay, consistent with the proposed role of the GRS in memory-related processes.
authors.affiliation: Lab for Cortical Organization and Systematics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan. kurotani@brain.riken.jp
authors.forename: Tohru
authors.initials: T
authors.lastname: Kurotani
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyashita
authors.forename: Marie
authors.initials: M
authors.lastname: Wintzer
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Konishi
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sakai
authors.forename: Noritaka
authors.initials: N
authors.lastname: Ichinohe
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Rockland
mesh_terms: D000200:Action Potentials; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051668:Delayed Rectifier Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D007700:Kinetics; D051662:Kv1.1 Potassium Channel / Q000235:genetics; D051665:Kv1.4 Potassium Channel / Q000378:metabolism; D007858:Learning; D008568:Memory; D009415:Nerve Net / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051672:Shal Potassium Channels / Q000378:metabolism; D009435:Synaptic Transmission
chemical_list: D051668:Delayed Rectifier Potassium Channels; C489293:Kcna1 protein, rat; D051665:Kv1.4 Potassium Channel; D026902:Potassium Channel Blockers; D051672:Shal Potassium Channels; D051662:Kv1.1 Potassium Channel; D011188:Potassium