THE ROLE OF THE DENTATE GYRUS IN THE IMPLEMENTATION OF THE HIPPOCAMPAL FUNCTIONS: EPILEPTIC BRAIN

Temporal lobe epilepsy (TLE) is characterized by loss of cells in the hippocampus, often leading to sclerosis, subsequent reorganization of the hippocampal network, and deficits in declarative memory. Despite the huge amount of experimental, preclinical and clinical studies, there is still a limited understanding of the main mechanisms underlying the development of TLE. There is an assumption that namely the dentate gyrus (DG) plays a main role in the mechanisms of the development of TLE. It is believed that during TLE development, the protective function of the DG, based on the low excitability of granular neurons is disturbed. In patients with temporal lobe epilepsy, a loss of mossy cells was found in the hilus of the DG. The vulnerability of mossy cells is considered a critical factor in the development of TLE: these neurons normally behave as circuit breakers, and their death disrupts the natural neural network, leading to the appearance of pathological activity. The proposed work examines the morphological and functional properties of DG in the epileptic brain, as well as the role of neurogenesis mossy fibers sprouting in the development of TLE. Impairment of cognitive functions of the hippocampus due to the loss of the dentate gyrus of its protective role is also under consideration. Special attention is paid to unresolved issues in these aspects.