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Interaural temporal disparities (ITDs) are a cue for localization of sounds along the azimuth. Listeners can detect ITDs in the fine structure of low-frequency sounds and also in the envelopes of high-frequency sounds. Sensitivity to ITDs originates in the main nuclei of the superior olivary complex (SOC), the medial and lateral superior olives (MSO and(More)
1. In most natural environments, sound waves from a single source will reach a listener through both direct and reflected paths. Sound traveling the direct path arrives first, and determines the perceived location of the source despite the presence of reflections from many different locations. This phenomenon is called the "law of the first wavefront" or(More)
We studied the interaural phase sensitivity of 85 units in the inferior colliculus (IC) of the unanesthetized rabbit. We assessed this sensitivity at several frequencies within each unit's responsive range. The interaural phase disparity was varied by delivering tones that differed by 1 Hz to the two ears, resulting in a 1-Hz binaural beat. We analyzed each(More)
The accuracy with which listeners can locate sounds is much greater than the spatial sensitivity of single neurons. The broad spatial tuning of auditory neurons indicates that a code based on the responses of ensembles of neurons, a population code, must be used to determine the position of a sound in space. Here we show that the tuning of neurons to the(More)
None of the current electrical audiometric procedures, alone or in combination, has yet achieved the precision of conventional audiometric testing that is used to assess hearing in verbally capable children and adults. The reason for this, in part, lies in the use of stimuli which have a wide frequency content. We have measured scalp potentials which follow(More)
Interaural time differences (ITDs) are a major cue for localizing the azimuthal position of sounds. The dominant models for processing ITDs are based on the Jeffress model and predict neurons that fire maximally at a common ITD across their responsive frequency range. Such neurons are indeed found in the binaural pathways and are referred to as "peak-type."(More)
1. We studied the effects of sodium pentobarbital on 22 neurons in the inferior colliculus (IC) of the rabbit. We recorded changes in the sensitivity of these neurons to monaural stimulation and to ongoing interaural time differences (ITDs). Monaural stimuli were tone bursts at or near the neuron's best frequency. The ITD was varied by delivering tones that(More)
Most natural sounds (e.g., speech) are complex and have amplitude envelopes that fluctuate rapidly. A number of studies have examined the neural coding of envelopes, but little attention has been paid to the superior olivary complex (SOC), a constellation of nuclei that receive information from the cochlear nucleus. We studied two classes of predominantly(More)
The inferior colliculus (IC) is a major auditory structure that integrates synaptic inputs from ascending, descending, and intrinsic sources. Intracellular recording in situ allows direct examination of synaptic inputs to the IC in response to acoustic stimulation. Using this technique and monaural or binaural stimulation, responses in the IC that reflect(More)
1. The difference in the time of arrival of a sound at the two ears can be used to locate its source along the azimuth. Traditionally, it has been thought that only the on-going interaural temporal disparities (ITDs) produced by sounds of lower frequency (approximately less than 2 kHz) could be used for this purpose. However, ongoing ITDs of low frequency(More)