Human sound-localization behavior accounts for ocular drift.
To generate an accurate saccade toward a sound in darkness requires a transformation of the head-centered sound location into an oculocentric motor command, which necessitates the use of an eye-in-head position signal. We tested whether this transformation uses a continuous representation of eye position by exploiting the property that the oculomotor neural integrator is leaky with a time constant of ∼20 s. Hence in complete darkness, the eyes tend to drift toward a neutral position. Alternatively, the spatial mapping stage could employ a sampled eye-position signal in which case drift will not be accounted for. Our data show that the sound location is accurately represented and that the transformation uses a dynamic eye-position signal. This signal, however, is slightly underestimated, leading to small systematic localization errors that tend to covary with the direction of eye position.
Van Grootel
Tom J
TJ
Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Department of Biophysics, Nijmegen, The Netherlands.
Van Opstal
A John
AJ
D000328:Adult; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011434:Proprioception / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D013017:Sound Localization / Q000502:physiology*