title: Sound rhythms are encoded by postinhibitory rebound spiking in the superior paraolivary nucleus.
abstract: The superior paraolivary nucleus (SPON) is a prominent structure in the auditory brainstem. In contrast to the principal superior olivary nuclei with identified roles in processing binaural sound localization cues, the role of the SPON in hearing is not well understood. A combined in vitro and in vivo approach was used to investigate the cellular properties of SPON neurons in the mouse. Patch-clamp recordings in brain slices revealed that brief and well timed postinhibitory rebound spiking, generated by the interaction of two subthreshold-activated ion currents, is a hallmark of SPON neurons. The I(h) current determines the timing of the rebound, whereas the T-type Ca(2+) current boosts the rebound to spike threshold. This precisely timed rebound spiking provides a physiological explanation for the sensitivity of SPON neurons to sinusoidally amplitude-modulated (SAM) tones in vivo, where peaks in the sound envelope drive inhibitory inputs and SPON neurons fire action potentials during the waveform troughs. Consistent with this notion, SPON neurons display intrinsic tuning to frequency-modulated sinusoidal currents (1-15Hz) in vitro and discharge with strong synchrony to SAMs with modulation frequencies between 1 and 20 Hz in vivo. The results of this study suggest that the SPON is particularly well suited to encode rhythmic sound patterns. Such temporal periodicity information is likely important for detection of communication cues, such as the acoustic envelopes of animal vocalizations and speech signals.
authors: Department of Otolaryngology/Head Neck Surgery and Sensory Neuroscience Research Center, West Virginia University, Morgantown, West Virginia 26506-9303, USA.
authors: Richard A
authors: RA
authors: Felix
authors: Anders
authors: A
authors: Fridberger
authors: Sara
authors: S
authors: Leijon
authors: Albert S
authors: AS
authors: Berrebi
authors: Anna K
authors: AK
authors: Magnusson
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000502:physiology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001306:Auditory Pathways / Q000502:physiology; D001703:Biophysics; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism; D008012:Lidocaine / Q000031:analogs & derivatives / Q000494:pharmacology; D020748:Mibefradil / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009847:Olivary Nucleus / Q000166:cytology*; D010507:Periodicity; D015221:Potassium Channels / Q000378:metabolism; D011571:Psychoacoustics; D011743:Pyrimidines / Q000494:pharmacology; D011930:Reaction Time / Q000502:physiology; D013016:Sound; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D002121:Calcium Channel Blockers; D054815:Cyclic Nucleotide-Gated Cation Channels; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D007473:Ion Channels; D015221:Potassium Channels; D011743:Pyrimidines; C082246:ICI D2788; C012647:QX-314; D020748:Mibefradil; D013779:Tetrodotoxin; D008012:Lidocaine; D002118:Calcium