Factors defining a pacemaker region for synchrony in the hippocampus
- 31 October 2007
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 584 (3), 867-883
- https://doi.org/10.1113/jphysiol.2007.138131
Abstract
Synchronous activities of neuronal populations are often initiated in a pacemaker region and spread to recruit other regions. Here we examine factors that define a pacemaker site. The CA3a region acts as the pacemaker for disinhibition induced synchrony in guinea pig hippocampal slices and CA3b is a follower region. We found CA3a pyramidal cells were more excitable and fired in bursts more frequently than CA3b cells. CA3a cells had more complex dendritic arbors than CA3b cells especially in zones targetted by recurrent synapses. The product of the density of pyramidal cell axon terminals and dendritic lengths in innervated zones predicted a higher recurrent synaptic connectivity in the CA3a than in the CA3b region. We show that some CA3a cells but few CA3b cells behave as pacemaker cells by firing early during population events and by recruiting follower cells to fire. With a greater excitability and enhanced synaptic connectivity these CA3a cells may also possess initiating functions for other hippocampal ensemble activities initiated in this region.Keywords
This publication has 63 references indexed in Scilit:
- Hippocampal CA3 pyramidal cells selectively innervate aspiny interneuronsEuropean Journal of Neuroscience, 2006
- Geometric and functional organization of cortical circuitsNature Neuroscience, 2005
- Synaptic Contributions to Focal and Widespread Spatiotemporal Dynamics in the Isolated Rat SubiculumIn VitroJournal of Neuroscience, 2004
- Cell‐attached measurements of the firing threshold of rat hippocampal neuronesThe Journal of Physiology, 1999
- Molecular Characterization of a Putative K-Cl Cotransporter in Rat BrainJournal of Biological Chemistry, 1996
- Reactivation of Hippocampal Ensemble Memories During SleepScience, 1994
- Do septal neurons pace the hippocampal theta rhythm?Trends in Neurosciences, 1990
- Two-stage model of memory trace formation: A role for “noisy” brain statesNeuroscience, 1989
- Single neurones can initiate synchronized population discharge in the hippocampusNature, 1983
- Penicillin‐induced epileptiform activity in the hippocampal in vitro preparationAnnals of Neurology, 1977