Roles of inhibition in complex auditory responses in the inferior colliculus: inhibited combination-sensitive neurons.

Title

Roles of inhibition in complex auditory responses in the inferior colliculus: inhibited combination-sensitive neurons.

Creator

Nataraj Kiran; Wenstrup Jeffrey J

Publisher

Journal of neurophysiology

Date

2006
2006-04

Description

We studied the functional properties and underlying neural mechanisms associated with inhibitory combination-sensitive neurons in the mustached bat's inferior colliculus (IC). In these neurons, the excitatory response to best frequency tones was suppressed by lower frequency signals (usually in the range of 12-30 kHz) in a time-dependant manner. Of 143 inhibitory units, the majority (71%) were type I, in which low-frequency sounds evoked inhibition only. In the remainder, however, the low-frequency inhibitory signal also evoked excitation. Of these, excitation preceded the inhibition in type E/I units (16%), whereas in type I/E units (13%), excitation followed the inhibition. Type E/I and I/E units were distinct in the tuning and threshold sensitivity of low-frequency responses, whereas type I units overlapped the other types in these features. In 71 neurons, antagonists to receptors for glycine [strychnine (STRY)] or GABA [bicuculline (BIC)] were applied microiontophoretically. These antagonists failed to eliminate combination-sensitive inhibition in 92% (STRY), 93% (BIC), and 87% (BIC + STRY) of the type I units tested. However, inhibition was reduced in many neurons. Results were similar for type E/I and I/E inhibitory neurons. The results indicate that there are distinct populations of combination-sensitive inhibited neurons in the IC and that these populations are at least partly independent of glycine or GABAA receptors in the IC. We propose that these populations originate in different brain stem auditory nuclei, that they may be modified by interactions within the IC, and that they may perform different spectrotemporal analyses of vocal signals.

Subject

Acoustic Stimulation; Action Potentials/drug effects/physiology; Afferent/drug effects/*physiology; Animals; Auditory; Auditory Pathways/drug effects/*physiology; Bicuculline/pharmacology; Brain Stem/drug effects/*physiology; Chiroptera; Electrophysiology; Evoked Potentials; GABA-A Receptor Antagonists; GABA-A/physiology; Glycine/antagonists & inhibitors/physiology; Inferior Colliculi/*physiology; Neural Inhibition/drug effects/*physiology; Neurons; Receptors; Strychnine/pharmacology

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

2179–2192

Issue

4

Volume

95

Citation

Nataraj Kiran; Wenstrup Jeffrey J, “Roles of inhibition in complex auditory responses in the inferior colliculus: inhibited combination-sensitive neurons.,” NEOMED Bibliography Database, accessed February 28, 2021, https://neomed.omeka.net/items/show/4677.

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