Neural tuning matches frequency-dependent time differences between the ears.
The time it takes a sound to travel from source to ear differs between the ears and creates an interaural delay. It varies systematically with spatial direction and is generally modeled as a pure time delay, independent of frequency. In acoustical recordings, we found that interaural delay varies with frequency at a fine scale. In physiological recordings of midbrain neurons sensitive to interaural delay, we found that preferred delay also varies with sound frequency. Similar observations reported earlier were not incorporated in a functional framework. We find that the frequency dependence of acoustical and physiological interaural delays are matched in key respects. This suggests that binaural neurons are tuned to acoustical features of ecological environments, rather than to fixed interaural delays. Using recordings from the nerve and brainstem we show that this tuning may emerge from neurons detecting coincidences between input fibers that are mistuned in frequency.
Institut d'Etudes de la Cognition, Ecole Normale Supérieure, Paris, France.
Victor
V
Benichoux
Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, United States.
Bertrand
B
Fontaine
Laboratory of Auditory Neurophysiology, University of Leuven, Leuven, Belgium.
Tom P
TP
Franken
Laboratory of Auditory Neurophysiology, University of Leuven, Leuven, Belgium.
Shotaro
S
Karino
Laboratory of Auditory Neurophysiology, University of Leuven, Leuven, Belgium.
Philip X
http://orcid.org/0000-0002-9759-5375
PX
Joris
Institut d'Etudes de la Cognition, Ecole Normale Supérieure, Paris, France.
Romain
R
Brette
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D002415:Cats; D003056:Cochlear Nerve / Q000502:physiology*; D004423:Ear / Q000502:physiology*; D007245:Inferior Colliculi / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013016:Sound; D065855:Spatial Processing / Q000502:physiology*; D013997:Time Factors
auditory brainstem; cat; computational biology; electrophysiology; neuroscience; systems biology