Neurons in cat primary auditory cortex sensitive to correlates of auditory motion in three-dimensional space
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Amplitude modulation at the receiver's ears is a characteristic of moving sound sources. When a sound source moves from side to side, stimulus intensity decreases in one ear and increases in the other. When a sound source moves toward or away from the organism, the two ears receive correlated increases or decreases in sound level. We recorded from single cells in the auditory cortex while presenting amplitude modulated pure tones to the two ears which simulated motion either toward or away from the organism, or from side to side. Our results indicate that auditory cortex neurons can be highly sensitive to these correlates of auditory motion in three dimensional space. Three major classes of neurons were encountered. These included 1) neurons sensitive to azimuthal stimulus motion, 2) neurons sensitive to motion directly toward or away from the organism, and 3) monaural-like neurons. More toward-preferring neurons than away-preferring neurons were encountered, and more units preferred contralateral-directed than ipsilateral-directed movement. The different classes of direction-selective neurons were spatially segregated from each other within the cortex and appear to occur in columns. In addition to their selectivity for different directions of simulated sound source motion, auditory cortex neurons could also be highly selective to AM ramp rate and excursion; these are correlates of sound source velocity.
Key wordsAuditory cortex Depth Binaural interaction Motion Amplitude modulation
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- Altman JA (1987) Information processing concerning moving sound sources in the auditory centers and its utilization by brain integrative and motor structures. In: Syka J, Masterton RB (eds) Auditory pathway: structure and function. Plenum Press, New York, pp 349–354Google Scholar
- Gardner M (1968) Distance estimation of 0° or apparent 0°-oriented speech signals in anechoic space. J Acoust Soc Am 45:47–53Google Scholar
- Gourevitch G (1978) Directional hearing in mammals. In: Popper AN, Fay RR (eds) Comparative studies of hearing in vertebrates. Springer-Verlag, New York, pp 357–373Google Scholar
- Mendelson JR, Cynader MS (1983) Frequency disparity selectivity in cat primary auditory cortex (A1). Soc Neurosci Abs V9:955Google Scholar
- Mershon D, King L (1975) Intensity and reverberation as factors in the auditory perception of egocentric distance. Perception and Psychophysics 18:409–415Google Scholar
- Regan D, Beverley KI, Cynader M (1979) Stereoscopic subsystems for position in depth and for motion in depth. Proc R Soc B (London) 204:485–501Google Scholar
- Richards W, Regan D (1973) A stereo field map with implications for disparity processing. Investig Ophth 12:904–909Google Scholar