This research is designed to measure the effects of tendon vibrations on internal motor system models during movement. In essence, this experiment strives to combine research that postulates that 1). internal models of motor learning are based on joint coordinates and 2). research that indicates that tendon vibration influences sensation of joint extension and limb position. By combining these two areas of research, this research strives to construct a stronger understanding of internal models of motor control and the influence of tendon organs and muscle spindle afferents within these frameworks.
This research will be conducted in two phases, and will:
For both phases of the experiment, ear plugs and headphones will be used to prevent the subjects from hearing the sound of the vibrator, proposed to be a Mini-shaker type 4810, 1935497; Brüel & Kjär, Närum, Denmark. Subjects will not be able to see their arms through the use of a collar-type or planar divider between the subjects' eyes and arm.
The measurement of proprioceptive consequences of bicep tendon vibration at multiple frequencies during movement of the arm will be measured by having subjects extending their right arm to a target directly in front of them without being able to view their arm's movement. A single vibrator will be attached to their bicep tendon, and will be stimulated at ranges between 10 to 240 Hz, in 10 Hz increments. The amplitudes of vibration will be 2 mm, and will be rectangular pulse sequences that will vibrate the tendon tangentially. While vibrationally stimulated, the user will be asked to extend their arm to the target: three times for each of the 24 frequencies. It is presumed that different frequencies will produce unique target offset errors as a result of proprioceptive vibrational response.
To test the results of rotating the arm - and therefore lengthening the right bicep - the target will be moved 20 degrees to the right. All frequencies will be repeated, and the subject will be asked to move their right arm toward the target position for three times for each of the 24 vibrational frequencies.
The impact of tendon vibrations on internal models of joint coordinates is expected to indicate that excited muscle spindles and tendon organs only have an insignificant role in conveying an illusion of limb movement: motor areas of the brain are the prime conveyer of illusory arm position regardless of arm rotation.
However, this experiment may reveal irregular relationships at specific frequencies: unique frequencies may provide stimulation of muscle spindles and tendon organs that override motor areas of the brain. If this proves to be the case, this may provide a clearer model of the relationship between the activity in muscle spindle afferents, tendon organs and internal mental models of motor control.