Kv1.1 channel subunits are not necessary for high temporal acuity in behavioral and electrophysiological gap detection

The Kv1.1 potassium channel subunit, encoded by the Kcna 1 gene, is heavily expressed in the auditory brainstem and is thought to have a critical role in producing the high temporal precision of action potentials characteristic of the auditory system. Our intent was to determine whether temporal acuity was reduced in Kcria1 null-mutant (-/-) mice, compared to wild-type (+/+) and heterozygotic mice (+/-), as measured by the encoding of gaps in the inferior colliculus by near-field auditory evoked potentials (NFAEP) or behavioral gap detection (BCD) using a prepulse inhibition paradigm. NFAEPs were collected at 40, 60 and 80 dB SPL with gap durations from 0.5 to 64 ms. BGD data were collected using silent gaps in 70 dB noise from I to 15 ins in duration. There were no systematic effects of Kcna 1 genotype on NFAEP recovery functions, NFAEP latencies, or the time constant for BCD, but there was a small reduction in asymptotic prepulse inhibition for the longest gap stimuli in -/- mice. Gap thresholds were approximately 1-2 ms across genotypes, stimulus conditions, and paradigms. These data suggest that the neural pathways encoding behaviorally relevant, rapid auditory temporal fluctuations are not limited by the absence of Kv1.1 expression. (c) 2008 Elsevier B.V. All rights reserved.