Table 2.
Summary of analysis of hand movement data collected during fMRI.
| Target directed– no-visual feedback | Allocentric no- visual feedback | Target-directed visual feedback | Allocentric visual feedback | Sign. effects (p < 0.05) | |
|---|---|---|---|---|---|
| Average distance between targets (mm) | 28.7 | 27.6 | 28.7 | 28.0 | – |
| Average movement distance (mm) | 31.8 | 30.5 | 28.5 | 26.8 | – |
| Average distance error (mm) (with respect to target-to-target vector) | 3.1 | 2.9 | −0.2 | −1.2 | – |
| Average distance error (mm) (with respect to cursor-to-target vector) | 0.9 | 2.9 | 0.1 | −1.2 | – |
| SD distance error (mm) (with respect to target-to-target vector) | 7.1 | 7.2 | 1.5 | 4.3 | T, V, TxV |
| SD distance error (mm) (with respect to cursor-to-target vector) | 9.2 | 7.2 | 1.2 | 4.3 | T, V, TxV |
| Average direction error (degrees) (with respect to target-to-target vector) | 1.5 | 2.2 | −0.9 | 0 | V |
| Average direction error (degrees) (with respect to cursor-to-target vector) | 1 | 2.2 | −0.4 | 0 | V |
| SD direction error (degrees) (with respect to target-to-target vector) | 10.4 | 10.3 | 2.9 | 8.8 | T, V, TxV |
| SD direction error (degrees) (with respect to cursor-to-target vector) | 15.9 | 10.3 | 2.2 | 8.8 | T, V, TxV |
It is evident that subjects’ performance was accurate and reliable in all conditions, and that both constant and variable errors were smaller when visual feedback was available as compared to when it was not available. The effect of visual feedback seems stronger for the target-directed task. Data about distances are shown in physical touch panel coordinates. Visual display coordinates can be obtained by multiplying by 2.3 (see also Materials and Methods). Direction data are shown in degrees, which were the same physically and visually. The right column lists variables whose effects were found to be significant (p < 0.05) in repeated measures ANOVA with task (T) and visual feedback (V) as factors. Main effects are denoted by capital letters. Interaction effects are denoted by capital letters and “x.” For example, T × V denotes the interaction between task and visual feedback.