A quantitative study of auditory-evoked saccadic eye movements in two dimensions

We investigated the properties of human saccadic eye movements evoked by acoustic stimuli in the two-dimensional frontal plane. These movements proved to be quite accurate, both in azimuth and in elevation, grovided the sound source spectrum had a broad bandwidth and a sufficiently long duration. If the acoustic target was a tone, the azimuth of the saccadic end points remained equally accurate, whereas the elevation of the response was related to the frequency of the tone, rather than to the physical position of the target. Saccade elevation accuracy also declined substantially for short-duration noise bursts, although response elevation remained highly correlated with target elevation. The latencies of auditory saccades depended on the amplitude, but not on the direction of the eye movement, suggesting a polar coordinate origin of auditory saccade initiation. We also observed that the trajectories of auditory saccades were often substantially curved. Both a qualitative and a model-based analysis showed that this curvature corrected for errors in the initial direction of the saccade. The latter analysis also suggested that the kinematic properties of auditory saccades could be described by the superposition of two overlapping saccadic eye movements, hypothesized to be based on binaural difference cues and monaural spectral cues in the auditory signal, respectively. It is argued that, although the audio-oculomotor system has to operate in a feedforward way, it must nevertheless have access to an accurate representation of actual and desired eye position. Different models underlying the generation of auditory saccades are discussed.

[1]  C. Prablanc,et al.  Saccadic responses evoked by presentation of visual and auditory targets , 2004, Experimental Brain Research.

[2]  David L. Sparks,et al.  Sensori-motor integration in the primate superior colliculus , 1991 .

[3]  A. J. Van Opstal,et al.  Component stretching in fast and slow oblique saccades in the human , 2004, Experimental Brain Research.

[4]  Pascal Barone,et al.  Physiology of Thalamus and Cortex , 1992 .

[5]  C. J. Savage,et al.  Auditory-visual interaction in the generation of saccades in man , 2004, Experimental Brain Research.

[6]  John Van Opstal.  Representation of eye position in three dimensions , 1993 .

[7]  William H. Press,et al.  Numerical recipes in C , 2002 .

[8]  M. Cynader,et al.  A computational theory of spectral cue localization , 1993 .

[9]  D. Irvine.  Physiology of the Auditory Brainstem , 1992 .

[10]  William H. Press,et al.  Numerical Recipes in C, 2nd Edition , 1992 .

[11]  A. Opstal,et al.  Auditory-evoked saccades in two dimensions: Dynamical characteristics, influence of eye position, and Sound source spectrum , 1994 .

[12]  D. Sparks,et al.  Sensorimotor integration in the primate superior colliculus. I. Motor convergence. , 1987, Journal of neurophysiology.

[13]  A. Opstal,et al.  STIMULUS-INDUCED MIDFLIGHT MODIFICATION OF SACCADE TRAJECTORIES , 1987 .

[14]  Laurence R. Harris,et al.  Small Saccades to Double-Stepped Targets Moving in Two Dimensions , 1984 .

[15]  H. Collewijn,et al.  Precise recording of human eye movements , 1975, Vision Research.

[16]  H. Collewijn,et al.  Human ocular counterroll: assessment of static and dynamic properties from electromagnetic scleral coil recordings , 2004, Experimental Brain Research.

[17]  K. Hepp,et al.  Calibration of three-dimensional eye position using search coil signals in the rhesus monkey , 1992, Vision Research.

[18]  Robert A. Butler,et al.  Binaural localization: Influence of stimulus frequency and the linkage to covert peak areas , 1993, Hearing Research.

[19]  Geoffrey E. Hinton,et al.  Learning internal representations by error propagation , 1986 .

[20]  A. J. Van Opstal,et al.  Three-dimensional analysis of strongly curved saccades elicited by double-step stimuli , 2004, Experimental Brain Research.

[21]  M. Hepp-Reymond,et al.  Eye and head movements to auditory targets , 2004, Experimental Brain Research.

[22]  L. Stark,et al.  The main sequence, a tool for studying human eye movements , 1975 .

[23]  P. E. Hallett,et al.  Retinal eccentricity and the latency of eye saccades , 1994, Vision Research.

[24]  J.A.M. van Gisbergen,et al.  Responses of the Saccadic System to Sudden Changes in Target Direction , 1982 .

[25]  T. Vilis,et al.  Computing three-dimensional eye position quaternions and eye velocity from search coil signals , 1990, Vision Research.

[26]  R A Butler,et al.  The linkage between stimulus frequency and covert peak areas as it relates to monaural localization , 1992, Perception & psychophysics.

[27]  D. M. Green,et al.  Sound localization by human listeners. , 1991, Annual review of psychology.

[28]  F. Wightman,et al.  A model of head-related transfer functions based on principal components analysis and minimum-phase reconstruction. , 1992, The Journal of the Acoustical Society of America.

[29]  A. J. van Opstal,et al.  Experimental test of two models for the generation of oblique saccades , 2004, Experimental Brain Research.

[30]  Zahn,et al.  The audioocular response: intersensory delay. , 1979, Sensory processes.

[31]  M. Frens,et al.  Spatial and temporal factors determine auditory-visual interactions in human saccadic eye movements , 1995, Perception & psychophysics.