Human sound-localization behaviour after multiple changes in eye position

Area of Science:

• Neuroscience
• Oculomotor control
• Auditory perception

Background:

• Orienting gaze to peripheral sounds requires converting head-centered coordinates to eye-centered commands.
• Current models suggest saccadic control relies on efference copies of eye-displacement signals, not absolute eye position.
• This raises questions about how neural estimates of eye orientation maintain accuracy with repeated movements.

Purpose of the Study:

• To investigate whether the audiomotor system uses an accumulated estimate of eye position or actual eye position feedback for sound localization.
• To differentiate between two competing hypotheses of spatial accuracy in gaze control.

Main Methods:

• Head-restrained subjects performed voluntary eye movements in darkness for varying durations (0.2–15 s).
• Following eye movements, subjects oriented their eyes to a brief sound burst.
• The study analyzed the influence of accumulated oculomotor commands on sound localization responses.

Main Results:

• The audiomotor system's sound-localization response is programmed based on the actual eye position.
• Contrary to predictions, errors did not increase with the number of intervening eye movements.
• This suggests a reliance on real-time eye position feedback.

Conclusions:

• The neural basis for sound-guided gaze orienting relies on current eye position feedback.
• This mechanism ensures accurate spatial localization by bypassing the accumulation of noise from successive motor commands.
• The findings challenge models that rely solely on efference copies for precise oculomotor transformations.