Growth of the hippocampal formation in man.

The fresh volumes of the cortical area of the hippocampal formation were determined in 29 male, normative human brains ranging in age from 137 to 36,221 ontogenetic days inclusive of mid-gestation to the 99th postnatal year. The data were fitted by the 3-, 4-, and 5-parametric logistic functions. The ideal value P1 of the left hippocampal formation is 3 ml (SD = 0.1), the half-value time is 306 (SD = 32) ontogenetic days and the growth factor is 2.5 (SD = 0.4). The maximal daily growth rate of 8 mm3 occurs at approximately the half value time. According to the theory of Dobbing and Sands [1979], this period of rapid growth of the hippocampal formation with other brain regions suggests the existence of heterochronous development.