Contribution of displacement, duration, and velocity on auditory motion direction perception in macaque monkeys.

Motion perception is a key aspect of sensory processing that enables successful interaction with the environment. While visual motion perception has been extensively studied, little is known about the determinants of auditory motion perception. Our study explores how the perception of auditory motion direction changes with manipulations of low-level stimulus parameters in nonhuman primates (NHPs). Macaque monkeys were trained to perform a 2-AFC task in which they judged the direction of noisy auditory motion stimuli. We systematically manipulated stimulus duration, velocity, and displacement to evaluate their respective influence on motion sensitivity. Displacement had the greatest impact, while the relative influence of duration versus velocity depended upon the duration of the stimulus. These findings suggest that auditory motion direction is most likely processed by a snapshot mechanism, in which stimulus velocity is inferred by sequential snapshots of auditory stimulus location, rather than by velocity-selective motion detectors similar to those found in the visual system. To our knowledge, this study is the first to characterize the influence of low-level stimulus parameters on auditory motion perception in awake, behaving NHPs, and forms the basis for future neurophysiological investigations.