Alterations of functional connectivity in pilocarpine-induced mouse model of temporal lobe epilepsy in latent period

Abstract

Temporal lobe epilepsy is a neurological disorders that characterize abnormal electrical activities in hippo-campus as epileptic foci. During epileptogenesis, spontaneous recurrent seizures (SRSs) occurred and intro-duce to a chronic stage. Seizure-free period with no SRSs during epileptogenesis is important to early diagno-sis and medication of epilepsy. However, researches related to latent period of temporal lobe epilepsy are not well understood. Although few reports have been investigated this period in epilepsy mouse model, there is one previous study indicated that social behavior deficits and abnormal cortical activity appear in latent pe-riod. We could have questions about this underlying mechanisms that how can the epileptic mice show dis-ruptions of social behavior similar to chronic stage even though SRSs were not occurred in latent period. In human study, patients with temporal lobe epilepsy suffered from psychiatric comorbidities including depres-sion, anxiety, psychotic disorders, cognitive and personality changes and many research suggested that al-tered resting-state functional connectivity is associated with symptoms and psychiatric comorbidities. There-fore, we could hypothesize that resting-state functional connectivity is altered in several brain regions which has been associated various deficits of behavior. Furthermore, the resting-state functional connectivity map-ping with optical intrinsic signal imaging (fcOIS) recently reported that could investigate the large-scale brain networks in mice. Using this functional neuroimaging, we observed the changes of intrinsic functional connec-tivity in latent period of chronic epilepsy mouse model by seed-based functional connectivity analysis. We demonstrated that there were significant decreased functional connectivity in several brain regions related to deficits of behavior and symptoms of epilepsy. These results suggest that the psychopathology of epilepsy might be involved with the altered intrinsic functional connectivity and could help understanding about latent period that is important to early diagnosis of temporal lobe epilepsy.