Are there neurons detecting direction of sound source motion?

Discriminating external from self-produced sensory inputs is a major challenge for brains. In the auditory system, sound localization must account for movements of the head and ears, a computation likely to involve multimodal integration. Principal neurons (PNs) of the dorsal cochlear nucleus (DCN) are known to be spatially selective and to receive multimodal sensory information. We studied the responses of PNs to body rotation with or without sound stimulation, as well as to sound source rotation with stationary body. We demonstrated that PNs are sensitive to head direction, and, in the presence of sound, they differentiate between body and sound source movement. Thus, the output of the DCN provides the brain with enough information to disambiguate the movement of a sound source from an acoustically identical relative movement produced by motion of the animal.

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An Inverse Microphone Array Method for the Estimation of a Rotating Source Directivity

Acoustics ◽

10.3390/acoustics3030030 ◽

2021 ◽

Vol 3 (3) ◽

pp. 462-472

Author(s):

Simon Jekosch ◽

Ennes Sarradj

Keyword(s):

Sound Source ◽

Inverse Method ◽

Microphone Array ◽

Synthetic Data ◽

Directivity Pattern ◽

Microphone Arrays ◽

Spectral Matrix ◽

Source Directivity ◽

Directivity Patterns ◽

Source Motion

Microphone arrays methods are useful for determining the location and magnitude of rotating acoustic sources. This work presents an approach to calculating a discrete directivity pattern of a rotating sound source using inverse microphone array methods. The proposed method is divided into three consecutive steps. Firstly, a virtual rotating array method that compensates for motion of the source is employed in order to calculate the cross-spectral matrix. Secondly, the source locations are determined by a covariance matrix fitting approach. Finally, the sound source directivity is calculated using the inverse method SODIX on a reduced focus grid. Experimental validation and synthetic data from a simulation are used for the verification of the method. For this purpose, a rotating parametric loudspeaker array with a controllable steering pattern is designed. Five different directivity patterns of the rotating source are compared. The proposed method compensates for source motion and is able to reconstruct the location as well the directivity pattern of the rotating beam source.

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Role of pinnae and head movements in localizing pure tones 1The authors would like to thank Mr. Remi Humbert for implementing the experiment in Turbo Pascal and for his further assistance.

Swiss Journal of Psychology ◽

10.1024//1421-0185.58.3.170 ◽

1999 ◽

Vol 58 (3) ◽

pp. 170-179 ◽

Cited By ~ 4

Author(s):

Barbara S. Muller ◽

Pierre Bovet

Keyword(s):

Sound Source ◽

Head Movement ◽

Movement Analysis ◽

Head Movements ◽

Sound Sources ◽

Localization Accuracy ◽

Sound Effects ◽

Posterior Quadrant ◽

Localization Performance ◽

Pure Tones

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.

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