Audiogenic seizures visualized with transcranial autofluorescence imaging in the sensorimotor cortex of DBA/2 mice

Abstract

DBA/2 mice exhibit audiogenic seizures in response to strong sound stimuli, although the underlying cellular mechanisms are unknown. In the present study, we investigated cortical activities during strong sound stimuli in DBA/2 mice using flavoprotein autofluorescence imaging. DBA/2 mice (4–6 weeks old) were anesthetized by urethane. The skin was incised and the skull was exposed. The surface of the skull was covered with clear acrylic resin for keeping the skull transparent. Three days after the operation, the skull of the mice recovered from the operation were fixed under an epifluorescence binocular microscope with a CCD camera, and cortical activities during sound stimuli at 13 kHz for 60 s were visualized as autofluorescence changes. Electrocorticogram (ECoG) was also recorded. Autofluorescence responses were observed in the sensorimotor areas approximately 40 s after the onset of the sound stimuli. The maximal amplitude of lambdaF/F was lager than 5.0% and lasted for more than 90 s. Epileptic discharges recorded in ECoG were observed only in the sensorimotor areas, in which autofluorescence responses were observed. The present results suggest that epileptic foci for audiogenic seizures may be present in the sensorimotor cortex of DBA/2 mice. [Jpn J Physiol 55 Suppl:S151 (2005)]