Rapid online corrections for upper limb reaches to perturbed somatosensory targets: evidence for non-visual sensorimotor transformation processes

Abstract

When performing upper limb reaches, the sensorimotor system can adjust to changes in target location even if the reaching limb is not visible. To accomplish this task, sensory information about the new target location and the current position of the unseen limb are used to program online corrections. Previous researchers have argued that, prior to the initiation of corrections, somatosensory information from the unseen limb must be transformed into a visual reference frame. However, most of these previous studies involved movements to visual targets. The purpose of the present study was to determine if visual sensorimotor transformations are also necessary for the online control of movements to somatosensory targets. Participants performed reaches towards somatosensory and visual targets without vision of their reaching limb. Target positions were either stationary, or perturbed before (~450 ms), or after movement onset (~100 ms or ~200 ms). In response to target perturbations after movement onset, participants exhibited shorter correction latencies, larger correction magnitudes, and smaller movement endpoint errors when they reached to somatosensory targets as compared to visual targets. Because reference frame transformations have been shown to increase both processing time and errors, these results indicate that hand position was not transformed into visual reference frame during online corrections for movements to somatosensory targets. These findings support the idea that different sensorimotor transformations are used for the online control of movements to somatosensory and visual targets.

Auditory cues for somatosensory targets invoke visuomotor transformations: Behavioral and electrophysiological evidence

“…In the present study, reaction times were shorter when initiating movements to vibrotactile-cued somatosensory targets than auditory-cued somatosensory and visual targets. This result is consistent with studies showing that participants are faster when reacting to somatosensory stimuli than visual or auditory stimuli [26–28]. More relevant to the present study, reaction times significantly increased when participants gazed at the right fixation position when planning movements to auditory-cued somatosensory targets.…”

Online corrective responses following target jump in altered gravitoinertial force field point to nested feedforward and feedback control

“…This hypothesis is consistent with the observations made in several studies that the integration of sensorimotor information in a same coordinate system leads to smaller noise and bias than when different coordinate systems are involved (Manson et al 2019;Sarlegna et al 2009;Tagliabue and McIntyre 2011;Tong et al 2002). As a result, the use of a common sensory modality for encoding target position and controlling hand trajectory might induce smaller endpoint error and shorter correction latencies when the motor goal suddenly changes during reaching movements (Manson et al 2019;Reichenbach et al 2009). Then it follows that movement corrections could be impaired when the feedforward and feedback control involve different coordinate systems, particularly when the time for implementing these corrections is reduced as is the case with rapid movements.…”

Fundus-Vascular Responses to Color Deviation Caused by Non-Oxidative Blue Filtering

“…Whether human eyes benefit from non-oxidative blue filtering remained unclear. Researchers have performed ergonomic studies to clarify the effects of display brightness [15][16][17] on visual and nonvisual effects [18][19][20], whereas they focused little on the fundus-vascular responses to different color-gamut coverages and color-deviation levels.…”