The role of somatosensation in automatic visuo-motor control: a comparison of congenital and acquired sensory loss

Abstract

Studies of chronically deafferented participants have illuminated how regaining some motor control after adult-onset loss of proprioceptive and touch input depends heavily on cognitive control. In this study we contrasted the performance of one such man, IW, with KS, a woman born without any somatosensory fibres. We postulated that her life-long absence of proprioception and touch might have allowed her to automate some simple visually-guided actions, something IW appears unable to achieve. We tested these two, and two age-matched control groups, on writing and drawing tasks performed with and without an audio-verbal echoing task that added a cognitive demand. In common with other studies of skilled action, the dual task was shown to affect visuo-motor performance in controls, with less well-controlled drawing and writing, evident as increases in path speed and reduction in curvature and trial duration. We found little evidence that IW was able to automate even the simplest drawing tasks and no evidence for automaticity in his writing. In contrast, KS showed a selective increase in speed of signature writing under the dual-task conditions, suggesting some ability to automate her most familiar writing. We also tested tracing of templates under mirror-reversed conditions, a task that imposes a powerful cognitive planning challenge. Both IW and KS showed evidence of a visuo-motor planning conflict, as did the controls, for shapes with sharp corners. Overall, IW was much faster than his controls to complete tracing shapes, consistent with an absence of visuo-proprioceptive conflict, whereas KS was slower than her controls, especially as the corners became sharper. She dramatically improved after a short period of practice while IW did not. We conclude that KS, who developed from birth without proprioception, may have some visually derived control of movement not under cognitive control, something not seen in IW. This allowed her to automate some writing and drawing actions, but impaired her initial attempts at mirror-tracing. In contrast, IW, who lost somatosensation as an adult, cannot automate these visually guided actions.

Exploring crossmodal correspondences for future research in human movement augmentation

“…Studies on human motor control have proven that proprioception is an unobtrusive yet rich sensory modality allowing people to complete dextrous motor tasks with minimal attentional effort (Proske and Gandevia, 2012). This is further confirmed in patients who lost proprioception, and must continuously rely on visual monitoring to carry out daily life actions, with a huge attentional effort and lower learning performance (Danna and Velay, 2017;Miall et al, 2019Miall et al, , 2021. Hence, relaying proprioceptive-like information concerning SRLs (i.e., joint angle, end effector acceleration or exerted force) to the user can result in improved SRL control.…”

Affective Bodily Awareness

“…Hence, though they did not feel the location of their limbs from the inside, they still achieved perfect control with them. Interestingly, KS, another deafferented patient but who was born without proprioception and touch, also succeeds in controlling her body on the basis of vision only (Miall et al, 2021). Deafferentation thus falsifies O'Shaughnessy's view: action cannot require bodily awareness since deafferented patients manage to move successfully.…”

“…It appears that, at least in some of the deafferented patients, action monitoring had become automatic. For instance, the congenitally deafferented patient KS is able to write and draw in the same way as control participants, even when she has to simultaneously perform an audio-verbal echoing task that adds cognitive demand (Miall et al, 2021). 4 In addition, deafferented patients are not the only ones to use vision.…”

Visual context affects the perceived timing of tactile sensations elicited through intra-cortical microstimulation

“…Tactile sensation is highly important for executing dexterous, adaptable movements (Ghez et al, 1995;Miall et al, 2021Miall et al, , 2019Robles-De-La-Torre, 2006;Sainburg et al, 1995) and providing a sense of embodiment (Giummarra et al, 2008;Jeannerod, 2003;Tsakiris et al, 2010). In cases of spinal cord injury (SCI), motor and somatosensory abilities are impaired or fully lost below the level of the injury.…”