The Properties and Implications of Nmda Spikes in Neocortical Pyramidal Cells.
From: Department of Molecular and Cellular Physiology, Beckman Center B-139, Stanford University, Stanford, California 94305, USA. parhodes@stanford.edu
The Journal of neuroscience : the official journal of the Society for Neuroscience
- Publish Date: Jun 2006
- ISSN: 1529-2401
- Volume: 26
- Issue: 25
- Pages: 6704-15
- Medium: Internet
- Language: English
- Citation (JAMA): Rhodes Paul, et al. The Properties and Implications of Nmda Spikes in Neocortical Pyramidal Cells.. J. Neurosci. Jun 2006;26:6704-15
Abstract
Integration of synaptic input in dendritic trees is a nonlinear process in which excitatory input may elicit spikes localized within the branch receiving input. In addition to membrane current-driven events, a type of dendritic spike has recently been described that instead depends on NMDA receptor current. These NMDA spikes enable superlinear integration among inputs targeted close together on a single branch. Here a compartment model of a layer 5 pyramidal cell was used to examine the mechanisms underlying NMDA spikes and to test properties not directly accessible experimentally. The results indicate the following: initiation of an NMDA spike in a tertiary dendrite in 1 mm [Mg2+] requires an NMDA conductance density equivalent to 6-8 nS within a 25-microm-long dendritic subsegment; dendritic membrane currents are not required for NMDA spike production; and targeted dendritic (but not somatic) inhibitory input is exquisitely suited to veto an NMDA spike if it arrives within a 30 ms window in time. Finally, an analysis of the spatial density of NMDA conductance required for NMDA spike production implies that, at least up to the age (postnatal day 35) that these events have been observed, most of the excitatory synaptic conductance arriving at pyramidal cells is NMDA mediated.
Mesh Headings (Keywords): Action Potentials, Animals, Calcium, Dendrites, Dose-Response Relationship, Radiation, Electric Stimulation, Excitatory Amino Acid Agonists, Excitatory Postsynaptic Potentials, Models, Neurological, N-Methylaspartate, Neocortex, Neural Inhibition, Pyramidal Cells, alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
Check for Full Text / PubMed Unique Identifier (PMID): 16793878
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.