Monaural and binaural detection of sinusoidal phase modulation of a 500-Hz tone.

The detectability of phase modulation was measured for three subjects in two-alternative temporal forced-choice experiments. In experiment 1, the detectability of sinusoidal phase modulation in a 1500-ms burst of an 80-dB (SPL), 500-Hz sinusoidal carrier presented to the left ear (monaural condition) was measured. The experiment was repeated with an 80-dB, 500-Hz static (unmodulated) tone at the right ear (dichotic condition). At a modulation rate of 1 Hz, subjects were an order of magnitude more sensitive to phase modulation in the dichotic condition than in the monaural condition. The dichotic advantage decreased monotonically with increasing modulation rate. Subjects ceased to detect movement in the dichotic stimulus above 10 Hz, but a dichotic advantage remained up to a modulation rate of 40 Hz. Thus, although sound movement detection is sluggish, detection of internal phase modulation is not. In experiment 2, thresholds for detecting 2-Hz phase modulation were measured in the dichotic condition as a function of the level of the pure tone in the right ear. The dichotic advantage persisted even when the level of the pure tone was reduced by 50 dB or more. The findings demonstrate a large dichotic advantage which persists to high modulation rates and which depends very little on interaural level differences.

[1]  D W Grantham,et al.  Detection and discrimination of simulated motion of auditory targets in the horizontal plane. , 1986, The Journal of the Acoustical Society of America.

[2]  R A Reale,et al.  Auditory cortical neurons are sensitive to static and continuously changing interaural phase cues. , 1990, Journal of neurophysiology.

[3]  Juhani Hyva¨rinen,et al.  Auditory cortical neurons in the cat sensitive to the direction of sound source movement , 1974 .

[4]  Franco Lepore,et al.  Positional, directional and speed selectivities in the primary auditory cortex of the cat , 1997, Hearing Research.

[5]  D. H. Johnson,et al.  The relationship between spike rate and synchrony in responses of auditory-nerve fibers to single tones. , 1980, The Journal of the Acoustical Society of America.

[6]  D. Asdourian,et al.  Effects of thalamic and limbic system lesions on self-stimulation. , 1966, Journal of comparative and physiological psychology.

[7]  J. Goldberg,et al.  Response of binaural neurons of dog superior olivary complex to dichotic tonal stimuli: some physiological mechanisms of sound localization. , 1969, Journal of neurophysiology.

[8]  E Schorer,et al.  Critical modulation frequency based on detection of AM versus FM tones. , 1986, The Journal of the Acoustical Society of America.

[9]  R. Kay,et al.  On the existence in human auditory pathways of channels selectively tuned to the modulation present in frequency‐modulated tones , 1972, The Journal of physiology.

[10]  R. S. J. Frackowiak,et al.  Human cortical areas selectively activated by apparent sound movement , 1994, Current Biology.

[11]  J. Culling,et al.  Measurements of the binaural temporal window using a detection task , 1998 .

[12]  H. Wallach,et al.  The role of head movements and vestibular and visual cues in sound localization. , 1940 .

[13]  Philip H Smith,et al.  Projections of physiologically characterized spherical bushy cell axons from the cochlear nucleus of the cat: Evidence for delay lines to the medial superior olive , 1993, The Journal of comparative neurology.

[14]  D. P. Clarke,et al.  Monaural detection with contralateral cue (MDCC). 3. Sinusoidal signals at a constant performance level. , 1971, Journal of the Acoustical Society of America.

[15]  T. Yin,et al.  Interaural time sensitivity in medial superior olive of cat. , 1990, Journal of neurophysiology.

[16]  Brian C. J. Moore,et al.  Mechanisms underlying the frequency discrimination of pulsed tones and the detection of frequency modulation , 1989 .

[17]  Chandler Dw,et al.  Minimum audible movement angle in the horizontal plane as a function of stimulus frequency and bandwidth, source azimuth, and velocity. , 1992 .

[18]  M W Spitzer,et al.  Interaural phase coding in auditory midbrain: influence of dynamic stimulus features. , 1991, Science.

[19]  J. Harris,et al.  Monaural-binaural minimum audible angles for a moving sound source. , 1971, Journal of speech and hearing research.

[20]  M A Akeroyd,et al.  A binaural analog of gap detection. , 1999, The Journal of the Acoustical Society of America.

[21]  B Kollmeier,et al.  Binaural forward and backward masking: evidence for sluggishness in binaural detection. , 1990, The Journal of the Acoustical Society of America.

[22]  Dennis McFadden,et al.  Masking‐Level Differences Determined with and without Interaural Disparities in Masker Intensity , 1967 .

[23]  E. Zwicker,et al.  The four factors leading to binaural masking-level differences , 1985, Hearing Research.

[24]  J. Licklider,et al.  On the Frequency Limits of Binaural Beats , 1950 .

[25]  E. Zwicker,et al.  Binaural masking-level differences with tonal maskers , 1984, Hearing Research.

[26]  B. Moore,et al.  Temporal window shape as a function of frequency and level. , 1989, The Journal of the Acoustical Society of America.

[27]  Frederic L. Wightman,et al.  Detectability of varying interaural temporal differencesa) , 1978 .

[28]  T. Yin,et al.  Binaural interaction in low-frequency neurons in inferior colliculus of the cat. II. Effects of changing rate and direction of interaural phase. , 1983, Journal of neurophysiology.

[29]  J. E. Rose,et al.  Some neural mechanisms in the inferior colliculus of the cat which may be relevant to localization of a sound source. , 1966, Journal of neurophysiology.

[30]  L. Rayleigh,et al.  XII. On our perception of sound direction , 1907 .

[31]  M. W. Spitzer,et al.  Responses of inferior colliculus neurons to time-varying interaural phase disparity: effects of shifting the locus of virtual motion. , 1993, Journal of neurophysiology.