Marc Colonnier

Monoclonal antibodies reveal sagittal banding in the rodent cerebellar cortex

We have produced two monoclonal antibodies against polypeptide-associated antigens of developing rat cerebellum. One antibody recognizes an antigen associated with synaptic vesicles and another binds to a polypeptide which is restricted to the cytoplasm of a subset of cerebellar Purkinje cells. Both antibodies reveal the biochemical differentiation of the rodent cerebellar cortex into antigenically distinct sagittal zones.

Effects of the richness of the environment on six different cortical areas of the cat cerebral cortex.

The number and size of neurons and the cortical thickness were determined in areas 17, 18, 3B, 4 gamma, the posteromedial lateral suprasylvian area, and the primary auditive area of cats raised in an enriched and in an impoverished environment. A significant effect on the numerical density of neurons and on the size of the neuronal nuclei can be demonstrated in areas 17 and 18. We suggest that this preferential effect on occipital cortical regions is due to a different gradient of maturation among cortical regions.

A comparison of the number of neurons in individual laminae of cortical areas 17, 18 and posteromedial suprasylvian (PMLS) area in the cat.

The binocular region of area 17 (17B) has a greater number of neurons under a given unit of cortical surface (NC, number per column) than either the monocular region of area 17 (17M), area 18 or the posteromedial suprasylvian area (PMLS). The latter three areas follow the general principle of basic uniformity in the number of neurons under given units of cortical surface formulated by Rockel et al. This basic uniformity is maintained in layers I and II. The NC of other layers varies. The greatest differences are found in layer IV where the NC of each area is significantly different from that of each other area. Though the difference between layer IV of 17M and of either 18 and PMLS is largely offset by changes in the third layer, layers V (PMLS) and VI (18 and PMLS) also contribute to the compensation. The compensation between 18 and PMLS is due entirely to changes in layer VI. It is important to note that there are statistically demonstrable interindividual differences in the neuronal NC of the cats used in the present study. We suggest that these may be due to age, breeding, or rearing conditions, probably the latter.