Poster B119, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Feedforward Motor Enhancement of Auditory Sensory Thresholds
John Myers1, Jeffrey Mock1, Edward Golob1; 1University of Texas at San Antonio
When we move feedforward motor and feedback sensory systems exchange information to monitor our actions and their sensory consequences. Previous studies demonstrated that movement can influence perceptual judgments of loudness when comparing two stimuli. This study first asked whether feedforward motor systems influence auditory thresholds, a more basic measure of perception. Second, if thresholds are affected how specific is the perceptual bias relative to the expected sensory consequence of the movement? We tested subjects (n = 16) in two-phase motor conditions and a non-motor control. In the first motor phase subjects learned the association between pressing a button and a target tone (either 0.6 or 1.0 kHz) presented simultaneous to the press. In the second phase visual cues indicated when to press the button, and thresholds were tested for the target tone and two infrequent (p = 25%) non-target tones that were 20% higher/lower in frequency. The non-motor condition was the same except that visual cues did not elicit motor responses and only required that participants listen for tones. An incremental staircase procedure was applied to the tones to define thresholds. Results showed a trend for lower thresholds in the motor condition. There was also a main effect of frequency, indicating greatest sensitivity to targets and higher frequencies (p < 0.01). We conclude that feedforward motor commands may not only enhance auditory perception, but the enhancement may in part depend upon the expected sensory feedback.
Topic Area: PERCEPTION & ACTION: Motor control