Affordable Access

Overestimation of the electrical length of neuron dendrites and synaptic electrotonic attenuation.

Authors
  • Glenn, L L
Type
Published Article
Journal
Neuroscience Letters
Publisher
Elsevier
Publication Date
Aug 15, 1988
Volume
91
Issue
1
Pages
112–119
Identifiers
PMID: 3173782
Source
Medline
License
Unknown

Abstract

The electrical (also termed electrotonic) length of dendrites is a key factor in determining the magnitude of the decay of a postsynaptic potential as it propagates from the dendrites to the soma. The average electrotonic length of dendrites in spinal, hippocampal, and red nucleus neurons have been estimated at 1.2 (range of 0.9-1.5), based on single (equivalent) cylinder models. Synaptic potentials evoked at the terminals of dendrites that are 1.2 space constants in length have been estimated to decay 50% during propagation to the soma, the lost energy being dissipated as heat. The present analysis was conducted because a 50% propagation loss seemed unlikely for such a widespread neuron function as passive dendritic propagation. The explicit and implicit assumptions of the cylinder model were reconsidered. It was found that the simplifying assumption of uniform dendritic electrotonic length has led to a three-fold overestimate of dendritic electrotonic length by previous investigators. The conclusion is that dendrites have a typical electrotonic length of 0.4 rather than 1.2, therefore resulting in a propagation loss of only 7% rather than 50% for distal dendritic synapses.

Report this publication

Statistics

Seen <100 times