POSTNATAL-GROWTH OF DORSAL LATERAL GENICULATE-NUCLEUS OF CAT

The postnatal growth of the dorsal part of the lateral geniculate nucleus (LGNd) was studied in paraffin sections at the brains of 32 cats of known age. The changes in shape and position of the LGNd were described, and it was found that its volume increased from about 3.4 mm3 at birth to about 26.4 mm3 in the adult cat. When this value was corrected for shrinkage, the volume of the LGNd in the adult cat was about 44 mm3. Detailed measurements revealed that during the 2nd and 3rd week of postnatal life there was particularly steep increase in volume and that the final values were already reached at around the 40th day. Concomitant with the increase in volume there was a decrease of the number of cells per unit volume of grey matter. In the binocular segment of lamina A the number of cells decreased from about 470/(0.1 mm)3 at birth to between 95-130/(0.1 mm)3 in the adult cat. Separate measurements of nerve cells and neuroglial cells indicated that the absolute number of nerve cells remained fairly constant during postnatal life; between the 2nd and 6th wk a great number of neuroglial cells were newly formed.