Reciprocal facilitation between mental and visuomotor rotations

Abstract

Humans exhibit remarkably complex cognitive abilities and adaptive behavior in daily life. Cognitive operation in the "mental workspace," such as mentally rotating a piece of luggage to fit into fixed trunk space, helps us maintain and manipulate information on a moment-to-moment basis. Skill acquisition in the "sensorimotor workspace," such as learning a new mapping between the magnitude of new vehicle movement and wheel turn, allows us to adjust our behavior to changing environmental or internal demands to maintain appropriate motor performance. While this cognitive and sensorimotor synergy is at the root of adaptive behavior in the real world, their interplay has been understudied due to a divide-and-conquer approach. We evaluated whether a separate domain-specific or common domain-general operation drives mental and sensorimotor rotational transformations. We observed that participants improved the efficiency of mental rotation speed after the visuomotor rotation training, and their learning rate for visuomotor adaptation also improved after their mental rotation training. Such bidirectional transfer between two widely different tasks highlights the remarkable reciprocal plasticity and demonstrates a common transformation mechanism between two intertwined workspaces. Our findings urge the necessity of an explicitly integrated approach to enhance our understanding of the dynamic interdependence between cognitive and sensorimotor mechanisms.

Figure 1

Schematics of Experiment 1. (a) The experimental procedure. (b) In the mental rotation task, participants were asked to respond whether a tilted letter (e.g., R) was a normal or a mirrored image. Four asymmetric letters (F, G, J, R) were presented as targets randomly in the tasks. (c) In the visuomotor training session, participants performed a visuomotor rotation (VMR; red border) task or a control reach task (blue border). In the VMR and control reach task: participants moved the cursor (small black dot) from the starting base (open circle) toward the target (big black dot), and the cursor direction (solid line) was rotated 45° clockwise from (VMR) or normally followed (control reach) the hand trajectory (dotted line).

Figure 2

Results of Experiment 1. (a) Reach error of VMR (red) and control reach (blue) groups in the baseline, visuomotor training, and visuomotor washout session. (b) Reaction time (RT) of mental rotation tasks in the VMR (pre: 1024 ± 62.04 ms (s.e.), post: 873.9 ± 45.24 ms) and control reach group (pre: 921.8 ± 39.08 ms, post: 829.6 ± 29.50 ms). Markers represent individual participants in the pre- (circle) and post-test (cross). Black horizontal lines represent the mean with standard errors of the mean in the corresponding group. (c) Reduction in the mental rotation (MR) rate (left) and the intercept (right) from the pre- to post-test in the two groups. Dots represent individual participants. Larger positive numbers indicate larger reduction, i.e., performance improvement. VMR group shows significantly larger MR-rate improvement (0.42 ± 0.11 ms/°) then the reach group after the visuomotor training session (− 0.05 ± 0.10 ms/°), while their intercept improvements are not different (101.2 ± 20.20 ms vs. 96.42 ± 19.96 ms). (d) Relation between the pre-test performance and the improvement after visuomotor training in the MR rate (left) and intercept (right) in each participant. In terms of MR rate, less efficient participants in the pre-test improve significantly more after the visuomotor training in the VMR group (y = 0.31*x−0.19; R² = 0.36, p = 0.011), while there was no difference in the control reach group (y = − 0.04*x + 0.01. R² = 0.01, p > 0.250). In terms of intercept, participants with a larger intercept in the pre-test shortened their RT more in both groups after training (VMR: y = 0.45*x−257.1, R² = 0.86, p < 0.001; control reach: y = 0.60*x−376.7, R² = 0.66, p < 0.001). In (a)–(d), the colors of the markers and lines correspond to visuomotor training groups as depicted in Fig. 1c (red: VMR and blue: control reach). Error bars indicate standard errors of the mean. An asterisk indicates significant difference between results for the two training groups (*p < 0.05, **p < 0.01, ***p < 0.001).

Figure 3

Results of Experiment 2. Reach error of VMR for the mental rotation group (a) and control color-discrimination group (b) in trial blocks 1–10 in the VMR pre-test and post-test. The pattern of lines and dots indicates test sessions (solid line/clear dot = pre-test, dotted line/crossed dot = post-test). (c) Learning rate (LR) of VMR tasks. Markers represent individual participants in the pre- (circle) and post-test (cross). Black horizontal lines represent the mean with standard errors of the mean in the corresponding group. In (a)–(c), the colors of the dots and lines correspond to visual training groups (green = mental rotation, orange = control color-discrimination). Error bars indicate standard errors of the mean. An asterisk indicates significant difference between results for the two training groups (*p < 0.05).