Аннотация:Prolonged epileptic seizures are known to cause neuronal death and lead to brain damage. Lesions in various brain regions can result in memory and cognitive impairment. Acute morphological abnormalities and changes in parameters of MRI signal are found during first days after prolonged seizures and can possibly predict further pathologic processes. We studied early and late changes in brain structures after prolonged severe seizures on lithium-pilocarpine model of status epilepticus (SE) in rats. MRI study of rat brain was performed 2, 7 and 30 days after SE. High-resolution T2 images and T2-maps were obtained, and total damaged area, hippocampal volume, and T2 relaxation time in hippocampus, entorhinal and piriform cortex, prefrontal cortex, thalamus and amygdala were calculated. A week after the MRI study, animals were tested in an open field. To investigate the ability of the animals to habituate to the new environment, the test was performed three times with 24-hour intervals. In addition, forced swim test and taste preference test were performed to evaluate depression. Two days after SE, the increase of T2 signal was found in hippocampus and associated structures. The patterns of brain damage in rats after SE varied considerably. All rats after SE demonstrated high motor activity in an open field and did not habituate in the new environment that could be the evidence of long-term spatial memory deficit. These rats also were hyperactive in the forced swim test, however about a half of them had anhedonia. Rats with large increase of T2 signal and considerable early changes found by MRI, tended to demonstrate higher activity in the open field in comparison with rats with less pronounced early MRI changes.