The postnatal development of frequency-place code and tuning characteristics in the auditory midbrain of the phyllostomid bat, Carollia perspicillata

Hear Res. 1994 Jun 1;76(1-2):133-46. doi: 10.1016/0378-5955(94)90095-7.


This report describes the postnatal development of hearing range, auditory sensitivity and tonotopy within the inferior colliculus (IC) of a mammal specialized for ultrasonic hearing. The experimental animal, Carollia perspicillata, has an adult hearing range of 7-110 kHz (characteristic frequencies) but lack any significant overrepresentation of a limited frequency band as known for rhinolophoid bats and Pteronotus. The audiogram of the newborn Carollia includes characteristic frequencies from 8 to 76 kHz, which is about 65% of the adult hearing range. As in adults, low frequencies are represented in the dorsolateral portion of the IC. However, at birth the ventromedial IC is non-responsive to acoustic stimulation up to intensities of 90 dB SPL. During development there is a progressive conversion of non-responsive IC areas into acoustically responsive slabs with characteristic frequencies above 76 kHz along the dorsolateral to ventromedial (low-to-high frequency) IC axis. This development is superimposed by a non-uniform shift of characteristic frequency: a decrease of CFs in dorsolateral regions, and an increase of CFs in ventromedial areas. The results suggest a bidirectional shift of frequency representation along the cochlear tonotopic axis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Aging / physiology
  • Animals
  • Animals, Newborn / growth & development*
  • Animals, Newborn / physiology
  • Audiometry / veterinary
  • Auditory Cortex / growth & development*
  • Auditory Cortex / physiology
  • Auditory Threshold / physiology*
  • Brain / growth & development
  • Brain / physiology
  • Chiroptera / growth & development*
  • Chiroptera / physiology
  • Electrophysiology
  • Inferior Colliculi / growth & development*
  • Inferior Colliculi / physiology
  • Ultrasonics
  • Vocalization, Animal