Article Figures & Data
Figures
- Figure 1.
Effect of stimulus location change and posture on laser-evoked vertex potentials (Experiment 1). Group-level average waveforms elicited by trains of three laser stimuli (S1-S2-S3). Displayed signals are recorded from the vertex (Cz, nose reference). S1 and S2 were always delivered on the same body site (hand [H] or foot [F]). S3 was always delivered on the hand. Thus, S3 was delivered either on the same body site as S1 and S2 (HHH, no spatial change) or on a different body site (FFH, spatial change). During the experiment the subject held two postures: far (with the hand and foot ∼100 cm apart, top), and near (with the hand and foot next to each other, ∼10 cm apart, bottom). x-axis, time (s); y-axis, amplitude (μV). Scalp maps obtained at peak latency of the N2 and P2 waves show the vertex potential elicited by S3.
- Figure 2.
Effect of changes in posture and stimulus location on the laser-evoked vertex potential (Experiment 1). Left, Schematic of the 2 × 2 design used. Right, Statistical effects of the interaction for posture and spatial change on the S3 response, assessed using a repeated-measures ANOVA performed on each subject’s average waveform at the vertex (Cz; nose reference). Bar graphs represent group-level N2 and P2 wave amplitudes (mean ±SE). Scalp maps show the repeated-measures ANOVA results (F values) across all recorded electrodes, for the N2 and P2 waves. *p<0.05
- Figure 3.
Effect of stimulus location change and target limb on vertex potentials (Experiment 2). Group-level average waveforms elicited by S1, S2, and S3. Displayed signals are recorded from the vertex (Cz, nose reference). S1 and S2 were always delivered on the same body site (hand or foot). In the hand condition (top), S3 was delivered on the hand. Thus, when S3 was on a different body site than S1 and S2 (ie, in triplets FFH) the stimulation pattern produced a spatial progression of the stimulus toward the core of the body. In the foot condition (bottom), S3 was always on the foot. Thus, when S3 was on a different body site than S1 and S2 (ie, in triplets HHF) the stimulation pattern produced a spatial progression of the stimulus away from the core of the body. x-axis, time (s); y-axis, amplitude (μV). Scalp maps obtained at peak latency of the N2 and P2 waves show the vertex potential elicited by S3.
- Figure 4.
Significant interaction between the effects of stimulus location change and target limb on the N2 amplitude (Experiment 2). The N2 amplitude of the S3 response was assessed using a repeated-measures ANOVA performed on each subject’s average waveform at the vertex (Cz; nose reference). There was a significant target limb × spatial change interaction (F(1,11) = 13.89, p = 0.003), indicating that the N2 was significantly dishabituated only when the stimulus displacement produced a spatial progression toward the core of the body. Graph data represent mean ±SEM. Scalp maps show the repeated-measures ANOVA results (F values) across all electrodes, for the N2 and P2 waves.
- Figure 5.
Effect of stimulus location change and hand position on vertex potentials (Experiment 3). Group-level average waveforms elicited by S1, S2, and S3. Displayed signals are recorded from the vertex (Cz, nose reference). S1 and S2 were always delivered on the same body site (hand or foot). S3 was always delivered on the hand. Thus, S3 was delivered either on the same body site as S1 and S2 (HHH, no spatial change) or on a different body site (FFH, spatial change). During the experiment the subject held their hand in two alternative positions at the same height: either next to the left side of the trunk (condition near-to-trunk), or extended out to the left, as far away as possible from the trunk (condition far-from-trunk). x-axis, time (s); y-axis, amplitude (μV). Scalp maps obtained at peak latency of the N2 and P2 waves show the vertex potential elicited by S3.
Tables
F p N1 wave Main effect of posture 5.40 0.035 Main effect of spatial change 2.75 0.344 Interaction between posture and spatial change 4.63 0.048 N2 wave Main effect of posture 7.74 0.014 Main effect of spatial change 20.18 <0.001 Interaction between posture and spatial change 7.58 0.015 P2 wave Main effect of posture 1.31 0.270 Main effect of spatial change 0.68 0.424 Interaction between posture and spatial change 4.08 0.062 Significant effects (p<0.05) are highlighted in bold.
F p N2 wave Main effect of target limb 4.49 0.054 Main effect of spatial change 20.07 0.001 Interaction between target limb and spatial change 13.89 0.003 P2 wave Main effect of target limb 5.66 0.03 Main effect of spatial change 2.55 0.13 Interaction between target limb and spatial change 0.22 0.64 Significant effects (p<0.05) are highlighted in bold.
F p N2 wave Main effect of hand position 0.51 0.487 Main effect of spatial change 14.4 0.002 Interaction between target limb and spatial change 2.62 0.129 P2 wave Main effect of hand position 2.80 0.118 Main effect of spatial change 3.03 0.105 Interaction between target limb and spatial change 0.11 0.741 Significant effects (p<0.05) are highlighted in bold.
Lines Data structure Type of test Power1 a Normal distribution RM-MANOVA 0.021 b (FFH far) Normal distribution Paired t test 7.95; 4.20, 11.69 c (FFH near) Normal distribution Paired t test 4.23; 0.75, 7.70 d (HHH far) Normal distribution Paired t test 10.07; 5.97, 14.18 e (HHH near) Normal distribution Paired t test 6.68; 3.22, 10.14 f Normal distribution RM-ANOVA 0.236 g Normal distribution RM-ANOVA 0.336 h Normal distribution Paired t test −0.84; −1.67, 0.0082 i Normal distribution Paired t test −3.86; −5.59, −2.14 j Normal distribution Paired t test −0.16; −0.25, 0.56 k Normal distribution Paired t test −1.14; −2.58, 0.30 l Normal distribution RM-ANOVA 0.214 m Normal distribution RM-MANOVA 0.129 n Normal distribution Paired t test 0.26; 0.10, 0.43 o (FFF) Non-normal distribution Wilcoxon signed rank test 0.98 p (FFH) Non-normal distribution Wilcoxon signed rank test 0.88 q (HHF) Normal distribution Paired t test 11.61; 6.26, 16.97 r (HHH) Normal distribution Paired t test 12.57; 7.78, 17.36 s Normal distribution RM-ANOVA 0.515 t Approximate normal distribution2 RM-ANOVA 0.017 u Normal distribution Paired t test −3.4; −4.99, 1.88 v Normal distribution Paired t test 0.12; −0.83, 1.1 w Normal distribution RM-MANOVA 0.034 x (FFH far) Normal distribution Paired t test 7.42; 1.11, 13.75 y (FFH near) Normal distribution Paired t test 9.02; 3.35, 14.69 z (HHH far) Normal distribution Paired t test 8.23; 1.93, 14.52 aa (HHH near) Normal distribution Paired t test 13.57; 3.99, 23.16 bb Normal distribution RM-ANOVA 0.168 cc Normal distribution Paired t test −2.88; −5.22, −0.55 dd Normal distribution Paired t test −4.88; −7.69, −2.07 ee Normal distribution RM-ANOVA 0.009 ↵1 Power for t tests is shown as: mean difference, lower bound of 95% confidence interval, upper bound of 95% confidence interval; Power for RM-ANOVA is partial η2 of interaction of interest; Power for Wilcoxon signed rank test is test statistic/rank (W/S).
↵2 RM-ANOVA is robust against normality violations, and thus only requires approximate normal distribution. Only the P2 HHH condition violated the normality assumption based on the Shapiro–Wilks test.
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