Age reduces response latency of mouse inferior colliculus neurons to AM sounds

J Acoust Soc Am. 2004 Jul;116(1):469-77. doi: 10.1121/1.1760796.


Age and stimulus rise time (RT) effects on response latency were investigated for inferior colliculus (IC) neurons in young-adult and old CBA mice. Single-unit responses were recorded to unmodulated and sinusoidal amplitude modulated (SAM) broadband noise carriers, presented at 35 to 80 dB SPL. Data from 63 young-adult and 76 old phasic units were analyzed to identify the time interval between stimulus onset and driven-response onset (latency). When controlling for stimulus sound level and AM frequency, significant age-related changes in latency were identified. Absolute latency decreased with age at all stimulus AM frequencies, significantly so for equivalent rise times (RT) < or = 12.5 ms. The linear correlation of latency with AM stimulus RT was significant for both young-adult and old units, and increased significantly with age. It is likely that both the decrease in absolute latency and the increase in latency/RT correlation with age are consistent with a reduction of inhibitory drive with age in the IC. These latency changes will result in age-related timing variations in brainstem responses to stimulus onsets, and therefore affect the encoding of complex sounds.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aging / physiology*
  • Animals
  • Evoked Potentials, Auditory / physiology*
  • Inferior Colliculi / cytology
  • Inferior Colliculi / physiology*
  • Linear Models
  • Mice
  • Mice, Inbred CBA
  • Neurons / physiology*
  • Signal Processing, Computer-Assisted