Semi-invasive and non-invasive recording of visual evoked potentials in mice.

Abstract

Visual evoked potentials (VEPs) are used to assess visual function in preclinical models of neurodegenerative diseases. VEP recording with epidural screw electrodes is a common method to study visual function in rodents, despite being an invasive procedure that can damage the tissue under the skull. The present study was performed to test a semi-invasive (epicranial) and a non-invasive (epidermal) VEP recording technique, comparing them with the classic epidural acquisition method. Flash VEPs were recorded from C57BL/6 mice on three separate days within 2weeks. Waveforms, latencies and amplitudes of the components were compared between the three different methods, utilizing coefficient of repeatability, coefficient of variation and intersession standard deviation to evaluate reproducibility. While epidural electrodes succeeded in recording two negative peaks (N1 and N2), epicranial and epidermal electrodes recorded a single peak (N1). Statistical indexes showed a comparable reproducibility between the three techniques, with a greater stability of N1 latency recorded through epicranial electrodes. Moreover, N1 amplitudes recorded with the new less-invasive methods were more reproducible compared to the invasive gold-standard technique. These results demonstrate the reliability of semi- and non-invasive VEP recordings, which can be useful to evaluate murine models of neurological diseases.