The Study Of The Functional Changes On Rat Brain During Cognitive Task

Epilepsy is one of the most common neural diseases. The reason why temporal lobe epilepsy can cause cognitive impairment is unknown yet. Studies based on fMRI found that the default mode network also exists in rodents’ brain. Many DMN regions participate in the process of memory and cognition. However, the changes of DMN under cognitive impairment haven’t been fully studied.The lithium-pilocarpine model of temporal lobe epilepsy(TLE) rat model has similar pathological mechanism and clinical features as temporal lobe epilepsy patients. This study use the lithium-pilocarpine model of temporal lobe epilepsy(TLE) rat model as research object and execute the spatial memory task and non-spatial memory task. We collected the behavior and electroencephalogram(EEG) data synchronously. In this study, we discuss the changes of DMN in control group and TLE group, so that to understand the neural mechanism of epilepsy brain networkThe results are as follows,1. Both spatial and non-spatial memory is impaired on TLE group.2. The network analysis shows that rat’s default mode network has anterior and posterior subsystems. In spatial memory stage, the connectivity of low frequency(1~30Hz) signals in DMN increase, the connectivity of high frequency(30~80Hz) signals in DMN decrease. Compared with control group, this trend is more obvious in TLE group. In non-spatial memory stage, no significant change is observed. The connectivity of anterior-posterior DMN can be observed during the rest state, and the connectivity is increase during the explore state. Compared with the control group, the connectivity of anterior-posterior DMN in TLE group is decrease. The synchronism between left prefrontal lobe and other DMN regions in TLE group enhanced. These results suggest that DMN might mainly participate in spatial memory processing. The connectivity reduction of anterior-posterior DMN might relate to the cognitive impairment in TLE group. The hippocampus-prefrontal circuit might participate in memory processing and consolidation.3. Compared with the control group, the power of gamma band is reduced on hippocampus and temporal lobe in TLE group. The power of delta band is enhanced on temporal lobe in TLE group. It suggested that the major deficits of TLE rat might located at hippocampus and temporal lobe.