Format

Send to

Choose Destination
See comment in PubMed Commons below
J Neurophysiol. 2001 Apr;85(4):1377-83.

Mechanism for increased hippocampal synaptic strength following differential experience.

Author information

  • 1Department of Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-6209, USA. Tfoster@pop.uky.edu

Abstract

Exposure to novel environments or behavioral training is associated with increased strength at hippocampal synapses. The present study employed quantal analysis techniques to examine the mechanism supporting changes in synaptic transmission that occur following differential behavioral experience. Measures of CA1 synaptic strength were obtained from hippocampal slices of rats exposed to novel environments or maintained in individual cages. The input/output (I/O) curve of extracellularly recorded population excitatory postsynaptic potentials (EPSPs) increased for animals exposed to enrichment. The amplitude of the synaptic response of the field potential was related to the fiber potential amplitude and the paired-pulse ratio, however, these measures were not altered by differential experience. Estimates of biophysical parameters of transmission were determined for intracellularly recorded unitary responses of CA1 pyramidal cells. Enrichment was associated with an increase in the mean unitary synaptic response, an increase in quantal size, and a trend for decreased input resistance and reduction in the stimulation threshold to elicit a unitary response. Paired-pulse facilitation, the percent of response failures, coefficient of variance, and estimates of quantal content were not altered by experience but correlated well with the mean unitary response amplitude. The results suggest that baseline synaptic strength is determined, to a large extent, by presynaptic release mechanisms. However, increased synaptic transmission following environmental enrichment is likely due to an increase in the number or efficacy of receptors at some synapses and the emergence of functional synaptic contacts between previously unconnected CA3 and CA1 cells.

PMID:
11287462
[PubMed - indexed for MEDLINE]
Free full text

LinkOut - more resources

Full Text Sources

Other Literature Sources

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center