Geometry and structural plasticity of synaptic connectivity

Armen Stepanyants, Patrick R. Hof, Dmitri B. Chklovskii

Research output: Contribution to journalArticlepeer-review

243 Scopus citations


Changes in synaptic connectivity patterns through the formation and elimination of dendritic spines may contribute to structural plasticity in the brain. We characterize this contribution quantitatively by estimating the number of different synaptic connectivity patterns attainable without major arbor remodeling. This number depends on the ratio of the synapses on a dendrite to the axons that pass within a spine length of that dendrite. We call this ratio the filling fraction and calculate it from geometrical analysis and anatomical data. The filling fraction is 0.26 in mouse neocortex, 0.22-0.34 in rat hippocampus. In the macaque visual cortex, the filling fraction increases by a factor of 1.6-1.8 from area V1 to areas V2, V4, and 7a. Since the filling fraction is much smaller than 1, spine remodeling can make a large contribution to structural plasticity.

Original languageEnglish
Pages (from-to)275-288
Number of pages14
Issue number2
StatePublished - 11 Apr 2002


Dive into the research topics of 'Geometry and structural plasticity of synaptic connectivity'. Together they form a unique fingerprint.

Cite this