Practice Effects of an Orofacial Motor Control Task on Vibrotactile Detection
Capacity in the Human Perioral System: Preliminary Data

R Andreatta, J Davidow

Recent investigations have demonstrated that the mode and rate of lip force recruitment differentially modulates low frequency (<50 Hz) vibrotactile detection thresholds (VDT) in the orofacial area (Andreatta and Barlow, 2003; Andreatta et al. 2003). It is posited that dynamic force-related perceptual gating may operate adaptively during the learning of oromotor actions. To assess this hypothesis, lower lip (LL) VDT’s were obtained from young adults prior to and after training on a dynamic low-level lip force control task. The force task consisted of continuously tracking (using visual feedback) a cursor moving sinusoidally at 2 Hz and calibrated to a peak-to-peak force endpoint of 0.2 N, using a lip rounding gesture. Vibrotactile inputs were delivered to the right LL vermilion at test frequencies of 5, 10, 50, and 150 Hz. LL-VDT assessment was performed simultaneously with the lip tracking task. A control condition to rule out attention artifact was conducted by disassociating the site of motor control from the stimulus loci. Preliminary results showed a reduction in the overall magnitude of LL-VDT elevation from pre- to post-training. This result suggests that force-related orofacial perceptual gating may constitute an adaptive mechanism that is modulated during different phases of lip motor skill acquisition.