Article Figures & Data
Figures
- Figure 1.
Block scheme of the experimental session. The session consisted of four consecutive conditions: tactile stimulation (TS), control, learning and tactile imagery (TI) organized in runs. Each run was a random mixture of 20 reference state (rst) trials (counting visual objects) and 20 somatosensory trials (or control with the same visual cue but no stimulation). Specifically, the TS condition had TS and rst trials, the control condition had control and rst trials, the learning condition had TS trials with decreasing stimulus amplitude and rst trials, and the TI condition had TI and rst trials. The duration of each trial was 6 s. Vibrotactile stimulation was composed of pulses of vibration of variable frequency.
- Figure 2.
A, Grand median (N = 17) time–frequency event related desynchronization/synchronization (ERD/S) distribution in the C3 channel during the tactile stimulation (TS), tactile imagery (TI). Blue shapes correspond to the level of desynchronization (ERD), red shapes correspond to synchronization (ERS). The gray mask indicates insignificant differences (p > 0.003, nonparametric cluster-level paired t test, p-level adjusted by Bonferroni correction). B, Grand median of the ERD/S time courses during tactile stimulation (TS), tactile imagery (TI) and control state. Color lines represent median values (median values were calculated within each subject over all trials and individual frequency ranges where ERD was detected, and then a grand median value was obtained). Color shapes show the corresponding 25th and 75th percentiles. The vertical dashed lines represent the time limit of the 6-s trial, while the horizontal line indicates the resting state.
- Figure 3.
A, Group median event related desynchronization/synchronization (ERD/S) topomaps of sensorimotor EEG μ-rhythmic activity in two active conditions and the control for all subjects (N = 17). Blue corresponds to the level of desynchronization (ERD), red corresponds to synchronization (ERS). B, The across-subjects significance maps visualized p-values derived from nonparametric permutation tests for all experimental conditions. Color defines the significance level. Red color marks electrodes in which there was across-subjects significance.
- Figure 4.
A, Median event related desynchronization/synchronization (ERD/S) topomaps of sensorimotor EEG β-rhythmic activity in two active conditions for all subjects (N = 17). Blue corresponds to the level of desynchronization (ERD), red corresponds to synchronization (ERS). B, The across-subjects significance maps visualized p-values derived from nonparametric permutation tests for all experimental conditions. Color defines the significance level. Red color marks electrodes in which there was across-subjects significance.
- Figure 5.
Group level (N = 17) ERD-values in the C3 channel for explored somatosensory conditions (tactile stimulation (TS), tactile imagery (TI), and control condition). Horizontal lines within the boxes, medians; boxes, interquartile range and [Q1 – 1.5*IQR; Q3 + 1.5*IQR] range is shown by whiskers. Circles represent mean values for the group; p-values are shown for the Wilcoxon signed-rank test.
Tables
Condition Runs Trials
(in one run)Active
trials,
totalTactile stimulation (TS) 1 20 TS + 20 rst 20 Control 1 20 control + 20 rst 20 Learning 2 20 TS (decreasing) + 20 rst 40 Tactile imagery (TI) 2 20 TI + 20 rst 40 - Table 2
Performed statistical analysis of sensorimotor ERD over C3 channel depending on the experimental condition
Comparisons Wilcoxon signed-rank test p-value μ-ERD TS vs TI 56.0 0.33 μ-ERD TS vs control 0.0 0.0003 μ-ERD TI vs control 0.0 0.0003 β-ERD TS vs TI 13.0 0.002 β-ERD TS vs control 1.0 0.0003 β-ERD TI vs control 46.0 0.14
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