EEG analysis for estimation of duration and inter-event intervals of seizure-like events recorded in vivo from mice

Rett syndrome is a neurodevelopmental disorder of the brain that affects females more often than males. Its cause is linked to the mutations within the gene encoding methyl CpG-binding protein 2 (MeCP2). Presently, there is little information regarding how the loss of MeCP2 affects brain activity. It has been documented that during awake but immobile state, the MeCP2 deficient mice exhibit spontaneous, rhythmic electroencephalogram (EEG) seizure-like events (SLEs) in the range of 6-9 Hz. In this study, we analyze the cortical EEG activity in female MeCP2-deficient mice over 24 hour recordings. Characterizing the SLE and inter-SLE durations by fitting to a gamma distribution we show similarity to previous in vivo epilepsy studies. These results suggest that the SLE and inter-SLE dynamics differ. More precisely, the SLE terminations appear to be a result of time-dependent mechanisms, whereas the inter-SLEs are a result of a random process.