Proportional enhancement of the illusion velocities induced by bi- and trimodal stimulation over the fastest unisensory illusion.

<p>Histograms are the mean (± SEM) “multisensory index” MSI = [(multisensory velocity – highest unisensory velocity )/highest unisensory velocity ]×100.</p

Typical recordings of clockwise angular deviations (°) copied by a participant and raw EMG activity (mV) in the extensor carpi ulnaris (ECU) and pollicis longus (PL) muscles during the three unimodal conditions.

<p>A- Muscle proprioceptive vibration at 80 Hz. B- Counterclockwise tactile disk rotation at 40°/s. C- Counterclockwise visual scene rotation at 40°/s.</p

Comparison between the mean illusion velocities (± SEM) induced by unimodal, bimodal and trimodal stimulation applied at Low, Medium or High stimulation intensities.

<p>The unimodal stimulation conditions are represented by empty geometric figures: yellow triangle for tactile (T), red diamond for muscle proprioception (P) and blue circle for visual (V) conditions. The bimodal conditions are represented by solid geometric squares: purple squares for proprio-tactile (TP), orange squares for proprio-visual (PV) and green squares for visuo-tactile (TV) co-stimulation. The trimodal conditions are represented by solid black squares (TPV). Statistical data are p-values obtained by two-way ANOVAs (post-hoc tests,*p<0.05, **p<0.01; NS: Not significant).</p

The effects of 5 levels of stimulation intensity on the perceptual and motor responses elicited by isolated proprioceptive (left column), tactile (central column) or visual (right column) stimulation.

<p>From top to bottom: Mean velocities (± S.D.) of the kinaesthetic illusions reproduced by the participants; Mean RMS (± S.D.) of EMG activity in the right extensor carpi ulnaris (ECU) and pollicis longus (PL) muscles;- Mean latencies (± S.D.) of the motor and perceptual responses; Mean gains (a.u.) of the perceptual responses (± S.D.), i.e., the ratio between the illusion velocity and the stimulation intensity.</p

Mean Latencies (ms) ±S.D. of kinaesthetic illusions induced by uni-, bi- and tri-modal stimulation applied at Low, Medium or High intensity level.

<p>Mean Latencies (ms) ±S.D. of kinaesthetic illusions induced by uni-, bi- and tri-modal stimulation applied at Low, Medium or High intensity level.</p

Self Hand > Other Hand.

<p>Voxel level threshold for both contrasts was set at 0.001 uncorrected and voxel level threshold was set at 0.05 FWE corrected. For visualization purpose, statistical maps are displayed on a single subject brain normalized onto the MNI template. Anatomical locations estimated using the Anatomy toolbox (Eickhoff et al. 2006; Eickhoff et al. 2007; Eickhoff et al. 2005) and the Anatomical Automatic Labeling (Tzourio-Mazoyer et al. 2002) are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131970#pone.0131970.t003" target="_blank">Table 3</a>.</p

Responses to the questionnaire that participants filled after the last training session (green) and after the fMRI session (blue) to assess ownership feeling over the video projected hand (question 1), the consistency of ownership feeling (question 2), and the vividness of the kinesthetic sensation (question 3).

<p>Histograms are mean responses (+ standard deviation) reported by all participants on 100 mm analogue scales. It is important to note that the Other Hand video was specifically selected so it did not induce any feeling of ownership nor any sensation of movement (cf methods section).</p

Statistical parametric maps for Self Hand > Other Hand and for Real movement > Baseline.

<p>Light blue = Self Hand > Other Hand; yellow = Real movement > Baseline; green = areas common to both contrasts. Voxel level threshold for both contrasts was set at 0.001 uncorrected and cluster level threshold was set at 0.05 FWE corrected. For visualization purpose, statistical maps are displayed on a single subject brain normalized onto the MNI template. Anatomical locations estimated using the Anatomy toolbox (Eickhoff et al. 2006; Eickhoff et al. 2007; Eickhoff et al. 2005) and the Anatomical Automatic Labeling (Tzourio-Mazoyer et al. 2002) are given in Tables <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131970#pone.0131970.t003" target="_blank">3</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131970#pone.0131970.t004" target="_blank">4</a>.</p