Spatiotemporal influences on the recognition of two-dimensional vibrotactile patterns on the abdomen.

Spatial and temporal factors are known to highly influence tactile perception, but their role has been largely unexplored in the case of two-dimensional (2D) pattern recognition. We investigated whether recognition is facilitated by the spatial and/or temporal separation of pattern elements, or by conditions known to favor perceptual integration, such as the ones eliciting apparent movement. 2D vibrotactile patterns were presented to the abdomen of novice participants.

Head Stability and Head-Trunk Coordination in Horseback Riders: The Contribution of Visual Information According to Expertise.

Maintaining equilibrium while riding a horse is a challenging task that involves complex sensorimotor processes. We evaluated the relative contribution of visual information (static or dynamic) to horseback riders' postural stability (measured from the variability of segment position in space) and the coordination modes they adopted to regulate balance according to their level of expertise. Riders' perceptual typologies and their possible relation to postural stability were also assessed.

Evaluation of heading performance with vibrotactile guidance: the benefits of information-movement coupling compared with spatial language.

This study quantified the effectiveness of tactile guidance in indicating a direction to turn to and measured its benefits compared to spatial language. The device (CAYLAR), which was composed of 8 vibrators, specified the requested direction by a vibration at the corresponding location around the waist. Twelve participants were tested in normal light and in total darkness with 3 guidance conditions: spatial language, a long tactile rhythm (1 s on/4 s off vibrations) providing a single stimulation before movement, and a short rhythm (200 ms on/200 ms off vibrations) allowing information-movement coupling during body rotation.

(De)stabilization of required and spontaneous postural dynamics with learning.

The present research examined how learning a new ankle-hip coordination influenced the preexisting postural repertoire. Standing participants learned a new ankle-hip coordination mode (relative phase of 90'). Before and after practice, postural patterns were evaluated in two different tasks.

Motion sickness and postural sway in console video games.

Objective: We tested the hypotheses that (a) participants might develop motion sickness while playing "off-the-shelf" console video games and (b) postural motion would differ between sick and well participants, prior to the onset of motion sickness.

Background: There have been many anecdotal reports of motion sickness among people who play console video games (e.g.

Motion sickness, console video games, and head-mounted displays.

Objective: We evaluated the nauseogenic properties of commercial console video games (i.e., games that are sold to the public) when presented through a head-mounted display.

Motion sickness, body movement, and claustrophobia during passive restraint.

Standing participants were passively restrained and exposed to oscillating visual motion. Thirty-nine percent of participants reported motion sickness. Despite passive restraint, participants exhibited displacements of the center of pressure, and prior to the onset of motion sickness the evolution of these displacements differed between participants who later became sick and those who did not.

Dynamics of learning new postural patterns: influence on preexisting spontaneous behaviors.

In stance, rotations around the hips and ankles typically exhibit a relative phase close to 20 degrees or 180 degrees . In 2 experiments, the authors studied the reciprocal influence of those coordination tendencies with learning an ankle-hip relative phase of 135 degrees . Before, during, and after learning a new mode of coordination, they assessed participants' (N = 24 in each experiment) spontaneous postural patterns with a tracking task in which no specific coordination was required.

Motion sickness preceded by unstable displacements of the center of pressure.

We exposed standing participants to optic flow in a moving room. Motion sickness was induced by motion that simulated the amplitude and frequency of standing sway. We identified instabilities in displacements of the center of pressure among participants who became sick; these instabilities occurred before the onset of subjective motion sickness symptoms.

Exploring coordination dynamics of the postural system with real-time visual feedback.

Differential performance over a wide range of possible postural coordination modes was investigated using 16 ankle-hip relative phase patterns from 0 degrees to 337.5 degrees. Participants were instructed to produce each coordination mode with and without real time visual feedback.