Table of defined ROIS and overview of activations.

<p>Table of defined ROIS and overview of activations.</p

Main effect and 2-way interactions in the fMRI data.

<p>Significant BOLD activation differences (the activation color-coding is depicted below the figures) in ROIs in z-, y-, x-planes (coordinates are depicted on top of each panel). (A) Main effect <i>belt</i> (on > off), (B) Main effect <i>date</i> (pre > post training), (C) Main effect <i>task</i> (homing > control task), (D) Main effect <i>group</i> (control > belt), (E) Interaction of <i>date</i> and <i>belt</i>, (F) Interaction of <i>date</i> and <i>task</i>. Captions color-coding ROIs in Fig 3(A)-(F): S1 lavender, S2 khaki, PPC light green, STG light gray, Insula baby blue, premotor cortex peach, SMA blue, cerebellum dark gray, caudate nucleus forest green, Hippocampus white, MST pink. (G-L) Blown ups of planes best depicting peak activations in ROIS of significant BOLD activation differences in two-way interactions: (G) Interaction <i>date x task</i>, peak activation of caudate nucleus, (H) Interaction <i>date x task</i>, peak activation of Cerebellum, (I) Interaction <i>date x belt</i>, peak activation of insula, (J) Interaction <i>date x belt</i>, peak activation of PPC, (K) Interaction <i>date x belt</i>, peak activation of MST, (L) Interaction <i>date x belt</i>, peak activation of S2, (S2 also depicted in I and K).</p

Schematics of the fMRI path integration task.

<p>(A) Screenshot of the virtual environment and the response arrow. A surface texture of minimal-lifetime dots provides optic flow during outward journeys. (B) Triangles used in the outward journey traveld by subjects. The first segment of each triangle had constant velocity and a duration of 4s. The length of the second segment was adjusted according to the prior turning angle to ensure a total travel duration of 12s in all trials. (C) Flow of the conditions. During path integration, subjects should point the response arrow back to the starting location. During control, subjects should replicated the angle of an arrow additionally presented at the first static scene of control trials. Figures taken from Keyser [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref058" target="_blank">58</a>] and under Creative Commons CC-BY-3 from Schumann [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref031" target="_blank">31</a>].</p

Factor ratings for the belt wearing and control group.

<p>Ratings for factors <i>trust in navigational ability</i> (black triangles), <i>tactile belt perception</i> (pink stars), <i>conscious belt perception</i> (light pentagons) and <i>space perception</i> (red circles) for the belt wearing group and <i>space perception</i> (blue squares) for the control group as a function of weeks. Ratings range from 1 to 5 (not agree to very agree), indicating a low or high rating for the factor, respectively. Dotted lines indicate fitted lines by a linear mixed model for each factor. Error bars are SEM.</p

Factor analysis of quantitative data of the weekly questionnaire for the belt wearing group.

<p>Factor analysis of quantitative data of the weekly questionnaire for the belt wearing group.</p

The sensory augmentation device.

<p>(A) For testing and demonstration purposes the MRI <i>feelSpace</i> belt in the scanner is wrapped around a dummy with cables connecting the vibrating piezo actuators to an external computer. (B, C) The portable <i>feelSpace</i> belt (1) consists of the following main components: 30 vibrotactile piezo actuators that are identical to those of the MRI compatible belt (2), compass-control unit (3), an electronic compass (4), piezo-control unit with identical control as the scanner unit (5), and battery packs (6). Figure A taken from Keyser [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref058" target="_blank">58</a>] and under Creative Commons CC-BY-3 from Schumann [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref031" target="_blank">31</a>].</p

Details of the <i>feelSpace</i> belt.

<p>(A) Individual vibration elements feature casing, strain relief of power supply, piezo ceramic bending actuators, and a stamp. (B) The MRI compatible belt is connected by 60 coaxial cables to a filter box, which in turn is connected to the scanner room’s Faraday shield. Figures taken from Keyser [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref058" target="_blank">58</a>] and under Creative Commons CC-BY-3 from Schumann [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166647#pone.0166647.ref031" target="_blank">31</a>].</p

Timetable of measurements.

<p>Timetable of measurements.</p

Single participant and group statistics of sleep EEG.

<p>(A) Hypnograms of a belt wearing participant demonstrating the distribution of sleep stages during the nights (abscissa) before and during training (top to bottom). REM sleep phases are marked in red. (B) Relative changes in the REM sleep duration for all belt wearing participants and controls during the training period. (C, D) Learning-dependent changes in the sigma power (12–16 Hz) during Stage 2 sleep at frontal (C) and central (D) electrodes in belt participants and in controls. Error bars depict SEM. Please note that SEM is influenced by variance as well as group size. An asterix indicates a significant effect.</p