Auditory responses in the cochlear nucleus of awake mustached bats: precursors to spectral integration in the auditory midbrain.

Title

Auditory responses in the cochlear nucleus of awake mustached bats: precursors to spectral integration in the auditory midbrain.

Creator

Marsh Robert A; Nataraj Kiran; Gans Donald; Portfors Christine V; Wenstrup Jeffrey J

Publisher

Journal of neurophysiology

Date

2006
2006-01

Description

In the cochlear nucleus (CN) of awake mustached bats, single- and two-tone stimuli were used to examine how responses in major CN subdivisions contribute to spectrotemporal integrative features in the inferior colliculus (IC). Across CN subdivisions, the proportional representation of frequencies differed. A striking result was the substantial number of units tuned to frequencies \textless23 kHz. Across frequency bands, temporal response patterns, latency, and spontaneous discharge differed. For example, the 23- to 30-kHz representation, which comprises the fundamental of the sonar call, had an unusually high proportion of units with onset responses (39%) and low spontaneous rates (53%). Units tuned to 58-59 kHz, corresponding to the sharply tuned cochlear resonance, had slightly but significantly longer latencies than other bands. In units tuned to frequencies \textgreater30 kHz, 31% displayed a secondary excitatory peak, usually between 10 and 22 kHz. The secondary peak may originate in cochlear mechanisms for some units, but in others it may result from convergent input onto CN neurons. In 20% of units tested with two-tone stimuli, suppression of best frequency (BF) responses was tuned at least an octave below BF. These properties may underlie similar IC responses. However, other forms of spectral interaction present in IC were absent in CN: we found no facilitatory combination-sensitive interactions and very few combination-sensitive inhibitory interactions of the dominant IC type in which inhibition was tuned to 23-30 kHz. Such interactions arise above CN. Distinct forms of spectral integration thus originate at different levels of the ascending auditory pathway.

Subject

Acoustic Stimulation/methods; Action Potentials/*physiology; Animals; Auditory; Brain Mapping; Brain Stem/*physiology; Chiroptera/*physiology; Cochlear Nucleus/*physiology; Evoked Potentials; Mesencephalon/physiology; Nerve Net/*physiology; Pitch Perception/*physiology; Wakefulness/physiology

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

88–105

Issue

1

Volume

95

Citation

Marsh Robert A; Nataraj Kiran; Gans Donald; Portfors Christine V; Wenstrup Jeffrey J, “Auditory responses in the cochlear nucleus of awake mustached bats: precursors to spectral integration in the auditory midbrain.,” NEOMED Bibliography Database, accessed June 17, 2021, https://neomed.omeka.net/items/show/4672.

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