Conductive hearing loss disrupts synaptic and spike adaptation in developing auditory cortex

Han Xu, Vibhakar C. Kotak, Dan H. Sanes

Research output: Contribution to journalArticlepeer-review

Abstract

Although sensorineural hearing loss (SNHL) is known to compromise central auditory structure and function, the impact of milder forms of hearing loss on cellular neurophysiology remains mostly undefined. We induced conductive hearing loss (CHL) in developing gerbils, reared the animals for 8 -13 d, and subsequently assessed the temporal features of auditory cortex layer 2/3 pyramidal neurons in a thalamocortical brain slice preparation with whole-cell recordings. Repetitive stimulation of the ventral medial geniculate nucleus (MGv) evoked robust short-term depression of the postsynaptic potentials in control neurons, and this depression increased monotonically at higher stimulation frequencies. In contrast, CHL neurons displayed a faster rate of synaptic depression and a smaller asymptotic amplitude. Moreover, the latency of MGv evoked potentials was consistently longer in CHL neurons for all stimulus rates. A separate assessment of spike frequency adaptation in response to trains of injected current pulses revealed that CHL neurons displayed less adaptation compared with controls, although there was an increase in temporal jitter. For each of these properties, nearly identical findings were observed for SNHL neurons. Together, these data show that CHL significantly alters the temporal properties of auditory cortex synapses and spikes, and this may contribute to processing deficits that attend mild to moderate hearing loss.

Original languageEnglish (US)
Pages (from-to)9417-9426
Number of pages10
JournalJournal of Neuroscience
Volume27
Issue number35
DOIs
StatePublished - Aug 29 2007

Keywords

  • Auditory cortex
  • Deafness
  • Excitability
  • Short-term depression
  • Spike frequency adaptation
  • Synaptic transmission
  • Temporal processing
  • Thalamocortical projection

ASJC Scopus subject areas

  • Neuroscience(all)

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