Integration of vestibular and proprioceptive signals for spatial updating

Abstract

Spatial updating during self-motion typically involves the appropriate integration of both visual and nonvisual cues, including vestibular and proprioceptive information. Here, we investigated how human observers combine these two non-visual cues during full-stride curvilinear walking. To obtain a continuous, real-time estimate of perceived position, observers were asked to continuously point toward a previously viewed target in the absence of vision. They did so while moving on a large circular treadmill under various movement conditions. Two conditions were designed to evaluate spatial updating when information was largely limited to either proprioceptive information (walking in place) or vestibular information (passive movement). A third condition evaluated updating when both sources of information were available (walking through space) and were either congruent or in conflict. During both the passive movement condition and while walking through space, the pattern of pointing behavior demonstrated evidence of accurate egocentric updating. In contrast, when walking in place, perceived self-motion was underestimated and participants always adjusted the pointer at a constant rate, irrespective of changes in the rate at which the participant moved relative to the target. The results are discussed in relation to the maximum likelihood estimation model of sensory integration. They show that when the two cues were congruent, estimates were combined, such that the variance of the adjustments was generally reduced. Results also suggest that when conflicts were introduced between the vestibular and proprioceptive cues, spatial updating was based on a weighted average of the two inputs.

Light touch and medio-lateral postural stability during short distance gait

“…Afterwards, he was asked to walk along the walkway at a comfortable pace. Use of that procedure is supported by prior demonstration of the ability to walk accurately to previously seen targets while walking blindfolded for relatively short distances [25]. Upon arrival at the finishing line, the subject was asked to remove the blindfold and return to the starting line.…”

Dependence of auditory spatial updating on vestibular, proprioceptive, and efference copy signals

“…2 and 3), and we calculate the weights that best explain our results. Notice that this approach amounts to assuming forced fusion [proposed previously for visual-vestibular (de Winkel et al 2015;Prsa et al 2012) and vestibular-proprioceptive (Frissen et al 2011) cue integration] in that gross conflicts across signals are ignored (i.e., when one or the other signal is set to 0). Another assumption of the model is that vestibular and proprioceptive estimates (V and P in Eq.…”

Resolving the active versus passive conundrum for head direction cells

“…This possibility appears even more likely if there is a reference change in the vestibular signal requiring involvement of cerebellar and commissural circuitry. Therefore, the conundrum of how the ascending pathway to the HD circuit is derived from a vestibular signal that is suppressed during active head movements, may in fact be one small part of a larger problem faced by the brain as it manipulates vestibular information derived from similar head movements under different behavioral conditions in order to yield accurate perceptions of directional heading (Dokka et al 2013; Frissen et al 2011; Zaidel et al 2013). …”