title: Seasonal plasticity of precise spike timing in the avian auditory system.
abstract: Vertebrate audition is a dynamic process, capable of exhibiting both short- and long-term adaptations to varying listening conditions. Precise spike timing has long been known to play an important role in auditory encoding, but its role in sensory plasticity remains largely unexplored. We addressed this issue in Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii), a songbird that shows pronounced seasonal fluctuations in circulating levels of sex-steroid hormones, which are known to be potent neuromodulators of auditory function. We recorded extracellular single-unit activity in the auditory forebrain of males and females under different breeding conditions and used a computational approach to explore two potential strategies for the neural discrimination of sound level: one based on spike counts and one based on spike timing reliability. We report that breeding condition has robust sex-specific effects on spike timing. Specifically, in females, breeding condition increases the proportion of cells that rely solely on spike timing information and increases the temporal resolution required for optimal intensity encoding. Furthermore, in a functionally distinct subset of cells that are particularly well suited for amplitude encoding, female breeding condition enhances spike timing-based discrimination accuracy. No effects of breeding condition were observed in males. Our results suggest that high-resolution temporal discharge patterns may provide a plastic neural substrate for sensory coding.
authors.affiliation: Neurobiology and Behavior Graduate Program, Virginia Merrill Bloedel Hearing Research Center, caras@nyu.edu.
authors.forename: Melissa L
authors.identifier: http://orcid.org/0000-0002-7594-5653
authors.initials: ML
authors.lastname: Caras
authors.affiliation: Hearing Research Center and Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215.
authors.forename: Kamal
authors.initials: K
authors.lastname: Sen
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Departments of Psychology, Otolaryngology-HNS, Physiology and Biophysics, and.
authors.forename: Edwin W
authors.initials: EW
authors.lastname: Rubel
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Departments of Psychology, Biology, University of Washington, Seattle, Washington 98195, and.
authors.forename: Eliot A
authors.initials: EA
authors.lastname: Brenowitz
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D005072:Evoked Potentials, Auditory; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D008297:Male; D009473:Neuronal Plasticity; D009474:Neurons / Q000502:physiology; D017440:Photoperiod; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D012621:Seasons; D046370:Sparrows
chemical_list: D012739:Gonadal Steroid Hormones
keywords: auditory; hormone; neural coding; plasticity; seasonal; spike timing