Tonotopic Tuning in a Sound Localization Circuit
Autor: | Adrienne L. Fairhall, Matthew H. Higgs, Sean J. Slee, William J. Spain |
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Rok vydání: | 2010 |
Předmět: |
Sound localization
Patch-Clamp Techniques Time Factors Physiology Acoustics Models Neurological Action Potentials Interaural time difference Chick Embryo In Vitro Techniques Neurotransmission Synaptic Transmission Membrane Potentials Postsynaptic potential Neural Pathways Modulation (music) Animals Computer Simulation Sound Localization Audio frequency Neurons Physics Neuronal Plasticity General Neuroscience Temperature Excitatory Postsynaptic Potentials Articles Electric Stimulation Acoustic Stimulation Synapses Excitatory postsynaptic potential Tonotopy Chickens Neuroscience |
Zdroj: | Journal of Neurophysiology. 103:2857-2875 |
ISSN: | 1522-1598 0022-3077 |
DOI: | 10.1152/jn.00678.2009 |
Popis: | Nucleus laminaris (NL) neurons encode interaural time difference (ITD), the cue used to localize low-frequency sounds. A physiologically based model of NL input suggests that ITD information is contained in narrow frequency bands around harmonics of the sound frequency. This suggested a theory, which predicts that, for each tone frequency, there is an optimal time course for synaptic inputs to NL that will elicit the largest modulation of NL firing rate as a function of ITD. The theory also suggested that neurons in different tonotopic regions of NL require specialized tuning to take advantage of the input gradient. Tonotopic tuning in NL was investigated in brain slices by separating the nucleus into three regions based on its anatomical tonotopic map. Patch-clamp recordings in each region were used to measure both the synaptic and the intrinsic electrical properties. The data revealed a tonotopic gradient of synaptic time course that closely matched the theoretical predictions. We also found postsynaptic band-pass filtering. Analysis of the combined synaptic and postsynaptic filters revealed a frequency-dependent gradient of gain for the transformation of tone amplitude to NL firing rate modulation. Models constructed from the experimental data for each tonotopic region demonstrate that the tonotopic tuning measured in NL can improve ITD encoding across sound frequencies. |
Databáze: | OpenAIRE |
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