[Ventromedial field of human tuber cinereum. Mechanical morphometry]

Abstract

A quantitative structural analysis of the ventromedial area of the human hypothalamus was performed using an automatic image analysing computer. We divided the ventromedial area into two nuclei, nucleus ventromedialis (N. vm.) and nucleus infundibularis (N. inf.). N. vm. was studied in 6 cases, N. inf. in 7 cases. The following findings were obtained: 1. No significant differences of cell population became apparent between the left and right sides of both nuclei. Aside from a female case above 80 years of age, so far, no correlation with cellular distribution of age and sex, respectively, could be established. 2. In N. vm. the distribution of large and small nerve cells depends on the region within this nucleus. Small nerve cells appear more frequent in the medial region than in the central and in the lateral regions. On the other hand, significant distributional differences of nerve cells in the dorsal, central, and basal regions as well as in oro-caudal direction are absent. Data of individual cases and their mean value are conforming. Cell density (cell number/volume) does not show any regional dependence both in the frontal plane and in the oro-caudal direction; it amounts to approximately 170/mum3 in the entire nucleus. 3. In the frontal plane plane N. inf. does not disclose marked regional differences of cell population. Large neurons are slightly more frequent in the basal-medial region as compared to the dorsal region. An 81-year-old woman displayed a conspicuous increase of large nerve cells in the basal and centrolateral regions, obviously hypertrophy of the potential "subventricular nucleus" as described by SHEEHAN and KOVACS, which is, in our opinion, a part of the N. inf. In young subjects (below the age of 40 years) the frequency of large nerve cells decreases in oro-caudal direction. Identical cell populations suggest that the cuadal end of N. inf. extends to the floor of the mammillary recessus. Cell density in the frontal plane appears higher in the centrolateral region (230/mum3) compared to the dorsal and basal regions (190-200/mum3). Cell density increases in oro-caudal extent; it decreases, however, in the most caudal part.