Intracortical synchronization pattern on the preclinical and clinical stages of absence epilepsy (analysis of wavelet bicoherence in WAG/Rij rats)
Laboratory of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, 117485, Moscow, Russia
2 Center for Coordination of Fundamental Scientific Activities, National Medical Research Center for Therapy and Preventive Medicine, 101990, Moscow, Russia
3 Institute of Cardiological Research, Saratov State Medical University, 410005, Saratov, Russia
4 Institute of Physics, Saratov State University, 410012, Saratov, Russia
Accepted: 26 October 2022
Published online: 9 November 2022
Here we examine the intracortical synchronization pattern in freely moving WAG/Rij rats (valid animal model of absence epilepsy). In all rats, electrocorticograms were recorded at the age 5 and 9 months (i.e., preclinical and clinical stages of absence epilepsy in epileptic subjects). To assess intracortical synchronization pattern, we measured wavelet bicoherence in unilateral (fronto-frontal) and bilateral (fronto-occipital) electrode pairs in five non-overlapping frequency bands (“1–4 Hz”; “5–9 Hz”; “9–12 Hz”; “12–14 Hz”; “14–20 Hz”) and two additional bands “0.5–1.5 Hz”; “10–14 Hz” bands. Bilateral fronto-frontal synchronization in epileptic subjects was lower than in non-epileptic ones only on the clinical stage of absence epilepsy. Unilateral fronto-occipital synchronization in epileptic rats was lower (“5–9 Hz” and “10–14 Hz”) than in non-epileptic ones only on preclinical stage. This finding may be interpreted as a marker of thalamo-cortical impairment associated with epileptogenic processes underlying long-term progression of absence epilepsy. We construct plots of synchronization patterns or diagnostic maps, which can be used for early diagnosis of absence epilepsy in predisposed subjects.
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