Highly nonrandom features of synaptic connectivity in local cortical circuits

Song, S., Sjöström, P. J., Reigl, M., Nelson, S., Chklovskii, D. B. (March 2005) Highly nonrandom features of synaptic connectivity in local cortical circuits. PLoS Biol, 3 (3). e68. ISSN 1545-7885 (Electronic)

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URL: http://biology.plosjournals.org/perlserv/?request=...
DOI: 10.1371/journal.pbio.0030068

Abstract

How different is local cortical circuitry from a random network? To answer this question, we probed synaptic connections with several hundred simultaneous quadruple whole-cell recordings from layer 5 pyramidal neurons in the rat visual cortex. Analysis of this dataset revealed several nonrandom features in synaptic connectivity. We confirmed previous reports that bidirectional connections are more common than expected in a random network. We found that several highly clustered three-neuron connectivity patterns are overrepresented, suggesting that connections tend to cluster together. We also analyzed synaptic connection strength as defined by the peak excitatory postsynaptic potential amplitude. We found that the distribution of synaptic connection strength differs significantly from the Poisson distribution and can be fitted by a lognormal distribution. Such a distribution has a heavier tail and implies that synaptic weight is concentrated among few synaptic connections. In addition, the strengths of synaptic connections sharing pre- or postsynaptic neurons are correlated, implying that strong connections are even more clustered than the weak ones. Therefore, the local cortical network structure can be viewed as a skeleton of stronger connections in a sea of weaker ones. Such a skeleton is likely to play an important role in network dynamics and should be investigated further.

Item Type: Paper
Uncontrolled Keywords: Animals Cell Communication physiology Neural Pathways physiology Neuronal Plasticity Neurons physiology Rats Signal Transduction Synapses physiology Visual Cortex physiology
Subjects: organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons

organs, tissues, organelles, cell types and functions > tissues types and functions > visual cortex
CSHL Authors:
Communities: CSHL labs > Chklovskii lab
Depositing User: CSHL Librarian
Date: March 2005
Date Deposited: 05 Jan 2012 14:16
Last Modified: 05 Jan 2012 14:16
URI: http://repository.cshl.edu/id/eprint/23256

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