A micrometric and cytophotometric study of the simultaneous development of the cerebellar cortex and dental function in the rat during the early post-natal period.

A study was made of the growth of two cerebellar lobules receiving trigeminal afferents, crus 1 (C1) and uvula (U) and another lobule which receives only vestibular afferents, nodulus (N). Growth factors were determined using micrometry and histophotometry. Times of growth end were compared with first masticatory movements. The end of the maturation period of U and the beginning of absorption of tough diet appeared on the 15th post-natal day (PND). The end of growth of C1 on the 18th PND coincided with functional appearance of molars. It was suggested that, in the rat, maturity of the cerebellar cortex in certain lobules could be related to the early stage of weaning.