Structural mechanisms to produce differential dendritic gains.

Journal Article (Journal Article)

The axons of sacral parasympathetic preganglionic neurons (PGNs) originate on a primary dendrite between 10 and 110 mum from the soma. Therefore, it was hypothesized that the location of the axon origin would impact the relative efficacy of ipsilateral and contralateral synaptic inputs. The morphology of two PGNs was reconstructed, and the transfer impedance was used to quantify the influence of synaptic inputs on the transmembrane potential at the axon initial segment. The ratio of ipsilateral transfer impedance to contralateral transfer impedance (termed the relative gain) was increased by 14-29% for axons originating from the dendrite vs. axons originating from the soma. The addition of 50 synchronized "gating" synapses on the proximal dendrites increased the relative gain by 17-38% when the axon originated from the dendrite, but only by 11-15% when the axon originated from the soma. The efficacy of synaptic inputs and the ability of proximal gating synapses to regulate synaptic efficacy were strongly influenced by the site of origin of the axon. The position of axon origin is an effective structural mechanism to regulate the relative efficacy of synaptic inputs arriving at different locations on the dendritic tree.

Full Text

Duke Authors

Cited Authors

  • Lee, DC; Jensen, AL; Schiefer, MA; Morgan, CW; Grill, WM

Published Date

  • February 2005

Published In

Volume / Issue

  • 1033 / 2

Start / End Page

  • 117 - 127

PubMed ID

  • 15694915

Electronic International Standard Serial Number (EISSN)

  • 1872-6240

International Standard Serial Number (ISSN)

  • 0006-8993

Digital Object Identifier (DOI)

  • 10.1016/j.brainres.2004.11.034


  • eng