(A) The participant stood on a force plate mounted to an ankle-tilt platform and was securely strapped to a rigid backboard. The ankle-tilt platform and backboard were independently controlled by …
(A) Experiment 1: raw traces of body position (black) and velocity (blue) for a single participant balancing on the robotic simulator for 60 s at different imposed delay conditions. Dashed lines …
(A) Whole-body position (°; black) and velocity (°/s; blue) traces of a representative participant when balancing in the first (left) and last (right) minute of training. During training trials, the …
Data are from pre-learning (n = 8), post-learning (n = 8), and retention (n = 7) conditions. (A) Coherence, gain, and cross-covariance between vestibular stimuli and rectified soleus EMG activity …
(A) A Bayesian estimation procedure was used to fit sigmoidal functions to perceptual responses. The proportion of correct responses (i.e., button pressed during delay period) was calculated for …
Data are presented across transition periods where time zero represents the transition point from baseline (20 ms) to 200 ms delayed balance control, which lasted for 8 s (between grayed out areas) …
Estimates were calculated by concatenating data from all eight participants.
Note that cross-covariance and impulse response functions now provide similar results after down-sampled to 50Hz. Both responses, however, have poor resolution when compared to the original …
Note that the impulse response functions already become noisy when the data are downsampled to 100Hz.
Normalized responses (left), non-normalized responses (center) and scaled non-normalized responses (right). All three approaches produce a similar outcome: vestibular-evoked response amplitudes …
Data are presented across transition periods, where the simulation transitioned from baseline to 200 ms delayed balance control, which lasted for 8s (between dashed red vertical lines). Top panel, a …
Delay | Learning | Delay × learning interaction | ||||
---|---|---|---|---|---|---|
Variable | F | p | F | p | F | p |
Sway velocity variance | ||||||
Exp 1: standing balance trials | F(5,59.15) = 14.98 | < 0.001 | N/A | N/A | N/A | N/A |
Exp 2: vestibular testing | F(5,111.26) = 33.89 | < 0.001 | F(2,113.19) = 46.65 | < 0.001 | F(10,111.25) = 5.72 | < 0.001 |
Exp 2: perceptual testing | F(6,118.83) = 31.00 | < 0.001 | F(2,121.47) = 25.82 | < 0.001 | F(12,118.83) = 2.08 | = 0.023 |
Other variables | ||||||
Exp 1: percent within limits | F(5,60) = 127.48 | < 0.001 | N/A | N/A | N/A | N/A |
Exp 2: cross-covariance | W(5) = 1158.86 | < 0.001 | W(2) = 70.57 | < 0.001 | W(7) = 90.89 | < 0.001 |
Exp 2: perceptual threshold | N/A | N/A | F(2,11.84) = 7.52 | = 0.008 | N/A | N/A |
For Exp 2, vestibular cross-covariance responses (peak-to-peak amplitudes) were analyzed using an ordinal logistic regression after rank transforming the data.
Delay (ms) | 20 | 100 | 200 | 300 | 400 | 500 |
---|---|---|---|---|---|---|
Pre-learning (n = 8) | ||||||
Cross-cov. (%EMG·mA) | 17.7/16.0 | 20.7/18.8 | 14.0/11.0 | 8.10/12.4 | 5.54/10.9 | 4.35/5.50 |
Sway velocity variance [°/s]2 | 0.18 ± 0.17 | 0.93 ± 0.58 | 6.52 ± 4.40 | 11.35 ± 5.10 | 16.79 ± 8.51 | 11.80 ± 6.53 |
Post-learning (n = 8) | ||||||
Cross-cov. (%EMG·mA) | 20.4/23.2 | 20.4/26.7 | 21.5/19.6 | 19.1/20.5 | 15.7/16.0 | 14.1/21.4 |
Sway velocity variance [°/s]2 | 0.05 ± 0.05 | 0.13 ± 0.09 | 0.54 ± 0.32 | 1.58 ± 0.74 | 4.20 ± 1.05 | 6.99 ± 2.61 |
Retention (n = 7) | ||||||
Cross-cov. (%EMG·mA) | 18.8/20.0 | 15.3/17.6 | 19.3/20.1 | 16.4/12.5 | 11.8/9.16 | 10.6/13.3 |
Sway velocity variance [°/s]2 | 0.09 ± 0.11 | 0.20 ± 0.12 | 0.90 ± 0.48 | 2.91 ± 1.25 | 5.51 ± 0.98 | 6.48 ± 3.51 |
Delay (ms) | 50 | 100 | 150 | 200 | 250 | 300 | 350 |
---|---|---|---|---|---|---|---|
No learning (n = 10)* | |||||||
Used trials (out of 200) | 197 | 194 | 195 | 196 | 195 | 198 | N/A |
Detections (% detected) | 8 (4%) | 60 (31%) | 128 (66%) | 172 (88%) | 186 (95%) | 198 (100%) | N/A |
Sway velocity variance [°/s]2 | 0.12 ± 0.05 | 0.57 ± 0.48 | 1.69 ± 1.21 | 3.71 ± 2.52 | 4.87 ± 2.62 | 6.32 ± 1.95 | N/A |
Detection time (s) | 3.8 ± 2.0 | 4.7 ± 2.0 | 4.0 ± 1.9 | 3.5 ± 1.8 | 2.9 ± 1.5 | 2.6 ± 1.2 | N/A |
Pre-learning (n = 8) | |||||||
Used trials (out of 160) | 148 | 151 | 147 | 147 | 150 | 151 | 152 |
Detections (% detected) | 20 (14%) | 46 (30%) | 111 (76%) | 132 (90%) | 146 (97%) | 151 (100%) | 152 (100%) |
Sway velocity variance [°/s]2 | 0.24 ± 0.27 | 0.45 ± 0.33 | 1.84 ± 1.36 | 4.01 ± 2.33 | 4.18 ± 1.38 | 5.09 ± 1.46 | 4.70 ± 1.64 |
Detection time (s) | 4.1 ± 2.1 | 3.7 ± 1.9 | 3.6 ± 1.8 | 3.2 ± 1.6 | 2.9 ± 1.6 | 2.4 ± 1.2 | 2.3 ± 1.1 |
Post-learning (n = 8) | |||||||
Used trials (out of 160) | 157 | 156 | 157 | 156 | 157 | 157 | 151 |
Detections (% detected) | 16 (10%) | 23 (15%) | 52 (33%) | 101 (65%) | 136 (87%) | 153 (97%) | 151 (100%) |
Sway velocity variance [°/s]2 | 0.11 ± 0.10 | 0.16 ± 0.13 | 0.40 ± 0.26 | 1.34 ± 1.09 | 2.20 ± 1.61 | 3.02 ± 2.33 | 3.70 ± 2.37 |
Detection time (s) | 4.2 ± 2.0 | 3.8 ± 2.4 | 4.1 ± 1.7 | 3.9 ± 1.7 | 3.4 ± 1.8 | 2.7 ± 1.3 | 2.2 ± 1.1 |
Retention (n = 5) | |||||||
Used trials (out of 100) | 96 | 93 | 98 | 98 | 96 | 98 | 92 |
Detections (% detected) | 8 (8%) | 21 (23%) | 40 (41%) | 50 (51%) | 71 (74%) | 84 (86%) | 92 (100%) |
Sway velocity variance [°/s]2 | 0.05 ± 0.03 | 0.13 ± 0.06 | 0.27 ± 0.15 | 0.84 ± 0.51 | 1.51 ± 0.76 | 1.89 ± 1.09 | 2.60 ± 1.05 |
Detection time (s) | 5.0 ± 1.7 | 4.2 ± 2.0 | 4.2 ± 2.2 | 3.8 ± 2.0 | 3.4 ± 1.8 | 3.1 ± 1.8 | 3.1 ± 1.4 |
Sway velocity variance and detection time are presented as mean ± SD.
*No learning group is an independent sample of participants that were not exposed to a 350 ms delay.