Transformation of temporal properties between auditory midbrain and cortex in the awake Mongolian gerbil

Maria Ter-Mikaelian, Dan H. Sanes, Malcolm N. Semple

Research output: Contribution to journalArticlepeer-review


The neural representation of meaningful stimulus features is thought to rely on precise discharge characteristics of the auditory cortex. Precisely timed onset spikes putatively carry the majority of stimulus-related information in auditory cortical neurons but make a small contribution to stimulus representation in the auditory midbrain. Because these conclusions derive primarily from anesthetized preparations, we reexamined temporal coding properties of single neurons in the awake gerbil inferior colliculus (IC) and compared them with primary auditory cortex (AI). Surprisingly, AI neurons displayed a reduction of temporal precision compared with those in the IC. Furthermore, this hierarchical transition from high to low temporal fidelity was observed for both static and dynamic stimuli. Because most of the data that support temporal precision were obtained under anesthesia, we also reexamined response properties of IC and AI neurons under these conditions. Our results show that anesthesia has profound effects on the trial-to-trial variability and reliability of discharge and significantly improves the temporal precision of AI neurons to both tones and amplitude-modulated stimuli. In contrast, IC temporal properties are only mildly affected by anesthesia. These results underscore the pitfalls of using anesthetized preparations to study temporal coding. Our findings in awake animals reveal that AI neurons combine faster adaptation kinetics and a longer temporal window than evident in IC to represent ongoing acoustic stimuli.

Original languageEnglish (US)
Pages (from-to)6091-6102
Number of pages12
JournalJournal of Neuroscience
Issue number23
StatePublished - Jun 6 2007


  • Adaptation
  • Amplitude modulation
  • Anesthetic effects
  • Auditory cortex
  • Binary coding
  • Inferior colliculus

ASJC Scopus subject areas

  • General Neuroscience


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