GABAergic inhibition contributes to pulse repetition rate-dependent frequency selectivity in the inferior colliculus of the big brown bat, Eptesicus fuscus.
This study examined the effect of bicuculline application on sharpness of frequency tuning curves (FTCs) of bat inferior collicular neurons plotted under three different pulse repetition rates (PRRs) of 10, 30 and 90 pulses per second. The sharpness of FTCs of collicular neurons, which was expressed in Q(n) (Q(10), Q(20), Q(30)) and bandwidths (90, 75 and 50% of the maximal response at the best frequency), improved with increasing PRR. However, this PRR-dependent frequency selectivity of collicular neurons was abolished during bicuculline application. This observation suggests that GABAergic inhibition contributes more effectively to sharpening of FTCs at higher than at lower PRRs.
Jen
Philip H-S
PH
Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA. jenp@missouri.edu
Wu
Chung Hsin
CH
Luan
Rui Hong
RH
Zhou
Xiaoming
X
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001306:Auditory Pathways / Q000187:drug effects / Q000502:physiology; D001309:Auditory Threshold / Q000187:drug effects / Q000502:physiology; D001640:Bicuculline / Q000494:pharmacology*; D002685:Chiroptera; D004455:Echolocation / Q000502:physiology; D018756:GABA Antagonists / Q000494:pharmacology*; D007245:Inferior Colliculi / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007478:Iontophoresis; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010897:Pitch Discrimination / Q000502:physiology*
D018756:GABA Antagonists; D001640:Bicuculline