QUANTITATIVE CYTOARCHITECTURAL ANALYSIS OF CELLULAR DEGENERATION IN THE DORSAL LATERAL GENICULATE NUCLEI OF CATS AND KITTENS WITH CEREBRAL HEMISPHERECTOMY

Quantitative morphometry was used to study the effects of maturationally dependent responses to brain trauma on the cytologic organization of the dorsal lateral geniculate nucleus (LGd). The left hemitelencephalon was removed in adult cats and in neonatal kittens and resultant changes in cell size and density were compared between these groups and with intact controls. Morphological changes were found bilaterally in all lesioned cats. Ipsilaterally, geniculate volume was reduced by 23% in kitten-lesioned cats and by 33% in adult-lesioned cats. The geniculate of both lesion groups contained fewer neurons in all laminae than did the nucleus of intact cats, but only the adult-lesioned cats showed a substantial increase in glial cell counts. Contralaterally, there was a tendency for a lower neuronal density in both lesion groups, but this was significant only for the A-laminae of adult-lesioned cats. Therefore, neonatal lesions spared more neurons bilaterally and produced minimal ipsilateral gliosis compared to the adult ablation. Results are discussed within the context of the "Gudden effect" which asserts that there is more retrograde degeneration in neonatal versus adult brain-lesioned animals. © 1991.