The temporal window of two-tone facilitation in onset units of the ventral cochlear nucleus.
Effects of a tone, not at the best frequency (BF), on the responses of onset units to BF tones were recorded in the ventral cochlear nucleus of the guinea pig. The off-BF tone was at a fixed non-excitatory sound level. When the two tones were gated simultaneously, a marked threshold facilitation was observed; however, no facilitation was observed if the off-BF tone burst was delayed by 5-10 ms. Facilitation in some units declined and was either absent or only just detectable, when the start of the off-BF tone preceded that of the BF by more than 10 ms. However, the responses of the majority of onset units were facilitated when the off-BF tone preceded the BF tone by as much as 20 ms. Similar results were obtained when the roles of the BF and off-BF tones were reversed. These data suggest that depolarization due to BF inputs is of shorter duration than that due to off-BF inputs.
Palmer
A R
AR
MRC Institute of Hearing Research, University of Nottingham, UK.
Winter
I M
IM
D000818:Animals; D001288:Attention / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D017626:Cochlear Nucleus / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D006168:Guinea Pigs; D010898:Pitch Perception / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*