title: The generation of direction selectivity in the auditory system.
abstract: Both human speech and animal vocal signals contain frequency-modulated (FM) sounds. Although central auditory neurons that selectively respond to the direction of frequency modulation are known, the synaptic mechanisms underlying the generation of direction selectivity (DS) remain elusive. Here we show the emergence of DS neurons in the inferior colliculus by mapping the three major subcortical auditory nuclei. Cell-attached recordings reveal a highly reliable and precise firing of DS neurons to FM sweeps in a preferred direction. By using in vivo whole-cell current-clamp and voltage-clamp recordings, we found that the synaptic inputs to DS neurons are not direction selective, but temporally reversed excitatory and inhibitory synaptic inputs are evoked in response to opposing directions of FM sweeps. The construction of such temporal asymmetry, resulting DS, and its topography can be attributed to the spectral disparity of the excitatory and the inhibitory synaptic tonal receptive fields.
authors.affiliation: Broad Fellows Program in Brain Circuitry and Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
authors.forename: Richard I
authors.initials: RI
authors.lastname: Kuo
authors.forename: Guangying K
authors.initials: GK
authors.lastname: Wu
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001306:Auditory Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D002586:Cesium / Q000494:pharmacology; D017626:Cochlear Nucleus / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007245:Inferior Colliculi / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D008012:Lidocaine / Q000031:analogs & derivatives / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology; D013788:Thalamus / Q000166:cytology / Q000187:drug effects / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D026902:Potassium Channel Blockers; C070614:neurobiotin; D002586:Cesium; C012647:QX-314; D019789:Tetraethylammonium; D001710:Biotin; D008012:Lidocaine