Neuronal Remodeling and Dendritic Spines: A Review

ABSTRACT

The neurons show remodeling in their dendritic arbor and spine/synapsenumber in many brain regions including the hippocampus, amygdala and the prefrontalcortex. The dendritic spine density is reported to be changed due to experiences andstressful conditions. The dendritic spines are the small protrusions arising from thedendritic shaft of the neurons. They have basic shapes as large mushroom spines, shortstubby spines and thin spines. The morphology of spines changes rapidly in response tovarious stimuli that may be internal such as hormones and external such as environmentalchanges. Dendritic spine density plays a major role in classification of principal neuronsi.e. multipolar and pyramidal neurons. The principal neurons may be classified as sparselyspinous, moderately spinous and heavily spinous on the basis of density of spine over thedendritic branches. In response to environment dendritic remodeling takes place in theform of spine shapes, spine turnover and spine density etc. Synaptic plasticity primarilytakes place in dendritic spines and enriched environment have positive effect while socialisolation have negative effect on synapse formation. Exposure of animals to environmentalcomplexity may improve the learning and memory by providing adaptive changes in thedendritic spine density.