6 research outputs found

    Superimposition of the event-related potentials (grand average, n = 8 subjects) evoked by the checkerboard (red traces) and the 3D-tunnel (blue traces) presentation recorded at the O2 electrode.

    No full text
    <p>A: The vertical arrow corresponds to image presentation (Checkerboard or 3D tunnel) highlighting the P100, P200 and P300 components. The lower raster line represents the statistical significance of ERP difference between the two conditions (<i>P</i> < 0.05, permutation test). B: Same display as in A, but here the vertical arrow indicates the presentation of the uniform gray image highlighting the P135 component. Note the occurrence of a sinusoidal profile in the delta frequency range. C: Scalp topographies of the power of delta oscillation (1Hz) corresponding to the checkerboard and the 3D-tunnel stimulation between 360 and 460 ms. Only the significant periods are illustrated and the significant electrodes (<i>P</i> < 0.05, permutation test) are displayed in the far right column.</p

    Event-related spectral perturbation (ERSP) and intertrial coherency (ITC) (grand average, n = 8 subjects) recorded at the O2 electrode.

    No full text
    <p>A: ERSP related to checkerboard stimulation preceded and followed by gray page condition, the related ERP traces are overlapping and indicate P100, P200, P300. B: ITC map corresponding to the same situation as A. C: Same display as in A but for the 3D tunnel stimulation. D: same display as in B, but for the 3D-tunnel stimulation.</p

    Short-term EEG dynamics and neural generators evoked by navigational images - Fig 6

    No full text
    <p>Event-related spectral perturbation (ERSP) evoked by the gray image in the context of the checkerboard (GrayCheck)(A,D,G) and the 3D-tunnel (GrayTun)(B,E,H) in the same display as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0178817#pone.0178817.g005" target="_blank">Fig 5</a>. The statistical differences observed between these two situations are indicated in C, F, I for the ERSP recorded in Fz, Cz, and Oz, respectively. The red arrows point to increased beta ERS in case of the GrayTun centered around 450 ms (F) and increased alpha ERS just after the onset of the GrayCheck. These ERPS analysis are corroborated by FFT topographies of the 10 Hz (J) and 15 Hz oscillations (K) where only the statistical periods are illustrated from respectively -40 ms before the gray image presentation to + 250 ms and from +240 ms after the gray image to + 50 ms after the image presentation. J and K maps are vertically adjusted in order to highlight the time transition marked by a rectangular frame between the 10 and 15 Hz maps. Note that significant electrodes (third column of J, K) are mainly bilaterally situated in the parieto-occipital areas (J) for the 10 Hz and mainly lateralized in the left side for the 15 Hz (K).</p

    Superimposition of the event-related potentials (ERP) (<i>paradigm 1</i>, grand averaged n = 8) corresponding to the presentation of the 3D-tunnel (blue) and checkerboard (red) patterns.

    No full text
    <p>Full scalp array of these ERP (128 electrodes, reference placed on the right earlobe)(center). The shaded areas indicate significant difference (<i>P</i> < 0.05, permutation test) in the ERP periods between the two conditions: pink, blue and green areas for P100, P200 and P300 periods, respectively. Recordings at the frontal locus (Fpz) highlighting N200 (top insert). Recordings at the occipital locus (Oz) highlighting P100 (left bottom insert). Recordings at the parietal locus (PPO6h) highlighting P300 (right bottom insert). The vertical lines indicate the stimuli onset. Calibration bar corresponds to 2 V, positivity up.</p

    Effects of directional change in the 3D-tunnel presentation (grand average, n = 12 subjects).

    No full text
    <p>A: Event-related spectral perturbation in occipital locus (O2 electrode) evoked by the same 3D-tunnel direction (1Dir) (left side) and the 4 different directions (4Dir) (middle) showing a significant theta ERS between 370–500 ms for the 3D-tunnel with 4 different directions (middle map) with respect to the 3D-tunnel with single direction (left map). The statistical map (permutation with Holms test <i>P</i> < 0.05) is given on the right side of A. B: Event-related potential recorded (O2 electrode) evoked in the same condition as in A. The statistical difference (<i>P</i> < 0.05, permutation test) centered on the P200 component is marked by the vertical gray rectangle in the third column. C: Topography of the delta oscillation during the presentation of only one direction of the 3D-tunnel (left column) and during the 4 different directions of the 3D-tunnel presentation (middle column). The third column represents the statistical map (permutation with Holms). D: Same displays as in C but for the theta oscillation. Only the significant periods are illustrated.</p

    Overview of the three different stimulation paradigms and experimental settings.

    No full text
    <p>A: paradigm 1, checkerboard images (upper line) were compared to 3D-tunnel (lower line) (four directions randomly presented, (Left, Right, Up, Down)) intermixed with uniform gray images. Each visual item was presented for 500 ms. 96 and 192 presentations were used for the checkerboard and the 3D-tunnel, respectively. B: paradigm 2, 3D-tunnel (same condition as in A) compared to 3D-tunnel one direction (Up)(lower line) intermixed with uniform gray images. C: paradigm 3, checkerboard, 3D-tunnel (Up) scrambled checkerboard (ScrCheck) and scrambled 3D-tunnel (ScrTun), were randomly presented intermixed with gray image. For all paradigms, a green fixation point was presented on the center screen. The participants were asked to maintain their eyes on a green fixation dot presented centrally. D: Experimental setup. The subject is equipped with an EEG-cap and looks straight-ahead through a form fitting facemask connected through a cylindrical tunnel to laptop screen centered on the line of gaze at a distance of 30 cm from the eyes.</p