Perceived radial translation during centrifugation

Abstract

Abstract. BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception. OBJECTIVE: To study whether centrifugation can induce a radial translation perception in the absence of visual cues. METHODS: To that end, we exposed 12 subjects to a centripetal acceleration with eyes closed. To avoid confounding with angular motion perception, subjects were fist rotated on-axis, and were shifted out fast and slow only after rotation sensation had vanished. They were asked for translation direction and velocity right after the shift-out, as well as after about 60 seconds of constant centrifugation. RESULTS: Independent of fast or slow shift-out, the vast statistically significant majority of trials yielded an inward radial translation perception, which velocity was constant after 60 seconds of constant centrifugation. CONCLUSIONS: We therefore conclude that during centrifugation, an inward radial translation perception does exist in humans, which perception reaches a constant, non-zero value during constant rotation, lasting for at least one minute. These results can be understood by high-pass filtering of otolith afferents to make a distinction between inertial and gravitational acceleration, followed by a mere integration over time to reach a constant velocity perception.

In-car speed estimations with real, virtual, and no view

“…Road rumble typically increases with increasing car speed, and may hence serve as a cue for the speed estimations. Path integration refers to the assumption that sensory afferents coding for acceleration are integrated by our central nervous system over time to obtain a sense of speed as yet [29]. These factors, however, cannot be decisive in explaining the lack of difference in speed estimations between the other conditions.…”