Visuo-proprioceptive recalibration and the sensorimotor map

Abstract

Spatial perception of our hand is closely linked to our ability to move the hand accurately. We might therefore expect that reach planning would take into account any changes in perceived hand position; in other words, that perception and action relating to the hand should depend on a common sensorimotor map. However, there is evidence to suggest that changes in perceived hand position affect a body representation that functions separately from the body representation used to control movement. Here we examined target-directed reaching before and after participants either did (Mismatch group) or did not (Veridical group) experience a cue conflict known to elicit recalibration in perceived hand position. For the reaching task, participants grasped a robotic manipulandum that positioned their unseen hand for each trial. Participants then briskly moved the handle straight ahead to a visual target, receiving no performance feedback. For the perceptual calibration task, participants estimated the locations of visual, proprioceptive, or combined cues about their unseen hand. The Mismatch group experienced a gradual 70 mm forward mismatch between visual and proprioceptive cues, resulting in forward proprioceptive recalibration. Participants made significantly shorter reaches after this manipulation, consistent with feeling their hand to be further forward than it was, but reaching performance returned to baseline levels after only 10 reaches. The Veridical group, after exposure to veridically-aligned visual and proprioceptive cues about the hand, showed no change in reach distance. These results are not fully consistent with a single common sensorimotor map, but could suggest multiple, interacting body representations.

Different sensory information is used for state estimation when stationary or moving

“…That is, we are specifically focusing on times when state estimation is reliant on sensory feedback alone. This stands in contrast to other studies in which individuals were asked to report their perception following actively generated movements (Block and Bastian, 2011, 2010; Block and Liu, 2023), in which state estimates could potentially additionally benefit from sensory predictions based on an efference copy of the ongoing motor command (Miall and Wolpert, 1996). Since sensory predictions provide an estimate of where the limb is expected to be at the current time, they can help overcome delays that would otherwise lead to out-of-date position estimates based on sensory feedback alone (Shadmehr et al, 2010).…”

“…Our study design also included another key distinction from prior work. In bimodal trials of prior studies, individuals were encouraged to integrate visual and proprioceptive information and report a single unified percept (e.g., Block and Bastian, 2011, 2010; Block and Liu, 2023; Reuschel et al, 2010; van Beers et al, 1999, 1996). These prior studies often presented surreptitious sensory mismatches with the intent that people should combine the two senses in some weighted manner to come up with an integrated position percept (Block and Bastian, 2010; 2011; Reuschel et al, 2010).…”

“…Sessions were spaced at least 1 week apart (average, 17 days). Sample sizes were chosen to be comparable to previous studies utilizing a similar task (e.g., Block and Bastian, 2010;Block and Liu, 2023;Reuschel et al, 2010). All participants were naïve to the purposes of this study and provided written informed consent.…”

“…Of these nineteen participants, four were excluded for inability to follow directions; thus, we included data from 15 participants (age 20-33 years, average 25.1 years, standard deviation 3.2 years; 10 identified as female, 5 identified as male). Sample sizes for each experiment were chosen to be comparable to previous studies utilizing a similar task (e.g., Block and Bastian, 2010; Block and Liu, 2023; Reuschel et al, 2010). All participants were naïve to the purposes of this study and provided written informed consent.…”