COLUMNAR ORGANIZATION OF PARAHIPPOCAMPAL GYRUS IN HUMAN BRAIN

Abstract

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Backwords. The parahippocampal region, as defined in this review, comprises the cortical regions that surround the rodent hippocampus including the perirhinal, postrhinal, and entorhinal cortices. Parahippocampal gyrus is very important in the memory process. All other pathways especially from telencephalon are involved in bringing information. Aim. This information is then processed here and through efferent roads is forwarded to hippocampus. Material and Methods. Twelve anatomical cadaver samples of parahippocampal gyrus from two hemispheres of the brain cortex of from the age of 25 to 85 were used. They were treated with 12% formalin, isolated and dehydrated, 1040 sections were prepared in transversal and frontal plane and colored with Nissl method. Results and Discussion. In the surface of para-hippocampal gyrus, small lumps with irregular shapes have been observed. These are more significant on the first and second layer, where the cells are grouped in an island like shape, where in the middle acellular spaces are observed. These cells are composed of stellar and polygonal cells, consisting of big nucleus and cytoplasm rich in chromatin. These changes are very unique and are observed only in parahippocampal gyrus, which correspond to entorhinal area. Their size is variable, though based on our results the transversal diameter is around 0.25 to 2 mm respectively, and the longitudinal diameter is from 0.4 to 2.4 mm respectively. Conclusions. Verruca hippocampi which define the boundaries of entorhinal area, can be observed in different sizes. Their number also differs from the right and left side, which indicates that there is an asymmetry of the entorhinal area.