Dendritic structure alterations induced by hypothyroidism in pyramidal neurons of the rat visual cortex.

In order to study the effect that neonatal hypothyroidism has on the whole morphology of pyramidal neurons of the cerebral cortex, the dendritic structure of these cells was defined by a set of 10 variables divided into two subsets, one composed of 7 variables defining the apical shaft and the other composed of 3 variables concerning the basal arborization. The canonical multivariate analysis applied to the measurements of these variables made on two groups of layer III pyramidal neurons belonging to 80-day-old control and thyroidectomized rats revealed that this disease only affects the development of the apical tuft region of those neurons. This result is in agreement with our previous finding concerning the effect of hypothyroidism on the dendritic densities of layer III pyramidal neurons (Dev. Brain Res., 28 (1986) 259-262).