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Updated: Jul 17, 2026

Analysis of Dendritic Spine Morphology in Cultured CNS Neurons
Published on: July 13, 2011
Non-synaptic dendritic spines in neocortex
J I Arellano1, A Espinosa, A Fairén
1Departamento de Neuroanatomia y Biologia Celular, Instituto Cajal (CSIC), Ave. Dr. Arce, 37, 28002 Madrid, Spain.
Abstract:
A long-held assumption states that each dendritic spine in the cerebral cortex forms a synapse, although this issue has not been systematically investigated. We performed complete ultrastructural reconstructions of a large (n=144) population of identified spines in adult mouse neocortex finding that only 3.6% of the spines clearly lacked synapses. Nonsynaptic spines were small and had no clear head, resembling dendritic filopodia, and could represent a source of new synaptic connections in the adult cerebral cortex.
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