Analysis Tools
hearing/vestibular/ear
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• apical and basal portions of the cochlea in P4 and P12 spiral ganglion neurons show enhanced outward potassium currents
• however, by P56, no differences in potassium currents are seen
• mice show age-dependent alterations in action potential and firing properties of spiral ganglion neurons along the contour of the cochlear axis
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nervous system
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• in pre-hearing mice at P4, action potentials recorded from spiral ganglion neurons have narrow variability in resting membrane potentials compared to wild-type mice
• at P4, action potentials of basal spiral ganglion neurons show reduced action potential latency, amplitude, and increased firing frequency while apical spinal ganglion neurons show smaller first evoked action potential amplitudes
• the interspike intervals of spontaneously active P4 spinal ganglion neurons are reduced compared to wild-type mice
• in P12 mice, at the onset of hearing, action potentials show enhanced after hypolarization, reduced action potential duration and threshold voltage in slowly adapting spiral ganglion neurons from the base of the cochlea, and a smaller amplitude of first spike in fast adapting spiral ganglion neurons from the apex
• action potential properties in 2 month old mice are similar to wild-type, except in basal spinal ganglion neurons which continue to show enhanced after hypolarization and in basal and slowly adapting spinal ganglion neurons which continue to show reduced inter-spike interval
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