Spike ripples in striatum correlate with seizure risk in two mouse models

• Published in: Epilepsy & behavior reports Vol. 18; p. 100529
• Main Authors: Shi, Wen, Zemel, Dana, Sridhar, Sudiksha, Mount, Rebecca A., Richardson, R. Mark, Eden, Uri T., Han, Xue, Kramer, Mark A., Chu, Catherine J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2022; Elsevier
• Subjects: Basal ganglia; EEG biomarker; Epilepsy; HFOs; IEDs; Spike-ripple; HFO; Basal ganglia; HFOs; Spike-ripple; EEG biomarker; Epilepsy; EEG; LFP; IEDs; 6-OHDA; HFO, high frequency oscillation; 6-OHDA, 6-hydroxydopamine; EEG, electroencephalogram; LFP, local field potential
• ISSN: 2589-9864; 2589-9864
• DOI: 10.1016/j.ebr.2022.100529

•We recorded electrographic seizures in the striatum in two rodent models.•We identified spike ripples in rodent striatum with similar features as observed in human hippocampus and cerebral cortex.•Spike ripple rate was increased in the post-infusion ictal and interictal periods compared to pre-infusion periods.•Spike ripples are a promising translational biomarker for seizure risk in rodent models. Epilepsy biomarkers from electroencephalogram recordings are routinely used to assess seizure risk and localization. Two widely adopted biomarkers include: (i) interictal spikes, and (ii) high frequency ripple oscillations. The combination of these two biomarkers, ripples co-occurring with spikes (spike ripples), has been proposed as an improved biomarker for the epileptogenic zone and epileptogenicity in humans and rodent models. Whether spike ripples translate to predict seizure risk in rodent seizure models is unknown. Further, recent evidence suggests ictal networks can include deep gray nuclei in humans. Whether pathologic spike ripples and seizures are also observed in the basal ganglia in rodent models has not been explored. We addressed these questions using local field potential recordings from mice with and without striatal seizures after carbachol or 6-hydroxydopamine infusions into the striatum. We found increased spike ripples in the interictal and ictal periods in mice with seizures compared to pre-infusion and post-infusion seizure-free recordings. These data provide evidence of electrographic seizures involving the striatum in mice and support the candidacy of spike ripples as a translational biomarker for seizure risk in mouse models.