Preferred directions of arm movements are independent of visual perception of spatial directions

Abstract

Directional preferences have previously been demonstrated during horizontal arm movements. These preferences were characterized by a tendency to exploit interaction torques for movement production at the shoulder or elbow, indicating that the preferred directions depend on biomechanical, and not on visual perception-based factors. We directly tested this hypothesis by systematically dissociating visual information from arm biomechanics. Sixteen subjects performed a free-stroke drawing task that required performance of fast strokes from the circle center toward the perimeter, while selecting stroke directions in a random order. Hand position was represented by a cursor displayed in the movement plane. The free-stroke drawing was performed twice, before and after visuomotor adaptation to a 30° clockwise rotation of the perceived hand path. The adaptation was achieved during practicing pointing movements to eight center-out targets. Directional preferences during performance of the free-stroke drawing task were revealed in ten out of the sixteen subjects. The orientation and strength of these preferences were largely the same in both conditions, showing no significant effect of the visuomotor adaptation. In both conditions, the major preferred directions were characterized by higher contribution of interaction torque to net torque at the shoulder as well as by relatively low inertial resistance and the sum of squared shoulder and elbow muscle torques. These results support the hypothesis that directional preferences are largely determined by biomechanical factors. However, this biomechanical effect can decrease or even disappear in some subjects when movements are performed in special conditions, such as the virtual environment used here.

A preferred pattern of joint coordination during arm movements with redundant degrees of freedom

“…4B. This anisotropic distribution of movement directions was similar to that we observed in all our previous studies of the free-stroke drawing task performed with horizontal arm movements Dounskaia et al 2014;Goble et al 2007;. The preference to produce strokes in the four diagonal directions is not apparent in the mean directional and group peak histograms in the U condition (Fig.…”

“…Subjects consistently preferred certain directions and avoided some other directions. Further investigations yielded a conclusion that the directional preferences were caused by a propensity to use a simplified pattern of shoulder and elbow control during which one of the two joints was rotated actively and the other joint was rotated predominantly passively by interaction torque Dounskaia et al , 2014Goble et al 2007;. The preference for this control pattern resulted in four preferred directions, the two longitudinal directions (along the lower arm axis) achieved through active shoulder motion and passive elbow motion and the two transverse directions (orthogonal to the lower arm axis) achieved through active elbow motion and passive shoulder motion.…”

Hand preference in fast-moving versus slow-moving actions in capuchin, Sapajus spp., and squirrel monkeys, Saimiri sciureus

“…Slow movements are visually guided and involve coordination of senses such as haptic (sense of touch), visual, kinaesthetic (sense of body and limb movement) or proprioceptive (sensibility of the nervous system to information arising from the muscles, joints and bones), allowing modulation in the course of the movement (Beaubaton, 1983;Jeannerod, 1983Jeannerod, , 1984Jeannerod, , 1990. Finally, in humans, some authors suggest that the hand preference depends on biomechanical factors and not on visual perception (Dounskaia, Wang, Sainburg, & Przybyla, 2014) as has also been suggested for foot preferences in birds (Tommasi & Vallortigara, 1999). In the course of evolution, hemispheric specialization emerged as motor complexity changed (Mutha, Haaland, & Sainburg, 2013).…”

Multifunctional Setup for Studying Human Motor Control Using Transcranial Magnetic Stimulation, Electromyography, Motion Capture, and Virtual Reality

“…For example, the locations of virtual targets can be scaled to ensure identical initial arm posture across subjects. Virtual reality also allows the manipulation of visual feedback during experiments, which is an invaluable tool in visuomotor research [1][2][3][4][5] .…”