[Effect of sensory deprivation on the lamina V pyramidal neurons in the rat cingulate gyrus].

Three groups of Wistar-rats were reared in the dark during different periods in their postnatal life: the first group was reared in the dark starting from birth for a period of four weeks, the second one from birth up to nine weeks of age and the third one from the fifth up to the ninth week postnatal. Two groups of control animals were reared under normal laboratory conditions from birth up to four or else up to nine weeks of age. The brains were processed according to a modified Golgi-Kopsch method. In lamina-V-pyramids of the gyrus cinguli there were evaluated lightmicroscopically for every group: length, number and distribution of spines on the main apical dendrites; on the apical oblique dendrites, too, these measures were made in the groups of four weeks of age (experimental and control animals). Main results are: 1. Rearing in the dark from birth up to the fourth week of age, i.e. during the early period of the postnatal brain development causes a growing-inhibition: the number of apical oblique dendrites (first order) was significantly decreased in comparison with the controls. The apical spines-values are not significantly altered. 2. Rearing in the dark from birth up to the ninth week of age as well as during the later postnatal development (from the fifth up to the ninth week) cause a statistically significant increase of spines values on the main apical dendrite. 3. These findings are discussed from a functional point of view and with the references.