Faculty Bibliography

The hippocampal formation was studied in 5 brains of younger (29 to 52 years of age) and 6 brains of elderly (61 to 89 years of age) subjects without signs of dementia, as well as in 11 brains of patients with Alzheimer's disease (65 to 91 years of age). The 8-microns-thick sections were stained either with cresyl violet, Weil method or with immunocytochemical methods for amyloid (4G8) and neurofibrillary tangles (Tau-1). Cell bodies, senile plaques and tangles were counted in all brains. In brains of patients with Alzheimer's disease a significant neuronal loss (about 56%) was observed in the second layer of the entorhinal cortex. The tangles/neurones ratio was very high (62.79.1%) in this layer. A great number of senile plaques were present in the whole hippocampal formation, especially in the molecular layer of the dentate gyrus (22.91.5 plaques/mm2) which is the termination zone of the perforant path. It seems therefore, that pathological alterations in Alzheimer's disease disrupt the main input to the hippocampal formation. In "physiological" ageing we did not observe changes in the density of neurones, although single tangles and plaques were found in all hippocampal areas. In elderly individuals 3.81.3% of neurones of the second layer revealed neurofibrillary pathology; a few plaques were found in various areas of the hippocampal formation. These observations may suggest only a slight decrease in number of neurones in the hippocampal formation. However, these changes cause a slight impairment of memory and learning often found in elderly individuals without dementia.

The morphometric analysis of some hypothalamic nuclei was performed on 20 brains of subjects of both sexes aged from 29 to 79 years. They were divided into two groups: below and above the age of 60. Supraoptic (SON), lateral tuberal (LTN) and lateral mammillary (LMN) nuclei were investigated. In the group of aged subjects a decrease in cross-section area of neuron nuclei was observed in all investigated structures, expressed most in the LTN. A considerable increase in the neuron density with age was found in the LTN. The size of neuron cell bodies and the number of neurons did not change significantly with age in any of the investigated nuclei.

The cytoarchitectonics of the nucleus of the lateral olfactory tract (NLOT) was studied on Nissl stained sections in 6 brains of adult Wistar rats by using morphometric methods. The neuronal density of layer III (11,866 +/- 547 mm-3) is on average about three times smaller than that of layer II (30,947 +/- 1110 mm-3). The average cross-section area of neurons in layer III (254.3 +/- 3.8 microns2) is about twice as large as that of neurons in layer II (115.8 +/- 0.8 microns2). The layer II is rather homogenous in contrast to layer III which possesses neurons of various size. Other morphometric parameters of layer II and III are also different.