Article Figures & Data
Figures
- Figure 1.
A, Subjects were trained with their right hand to move in a force-field environment and were tested for transfer of learning to their left hand. B, Abrupt-training condition in which the load was introduced suddenly (after 15 null-field trials). C, Gradual-training condition in which the force field was smoothly introduced. B, C, The initial angular deviation (mean ± 1 SE) is shown over the course of training for the right hand. Representative hand paths and compensatory forces for single subjects are shown. The dots show positions of the hand during movement and the vectors represent forces applied by the hand of the subject. deg.,Degree; dev., deviation.
- Figure 3.
A, Control 1. Trials performed in the null-field condition. From left to right, end of familiarization with the left hand (before), null-field catch trials over the course of learning with the right hand in the gradual-training condition (during training), and first trial to test for transfer of aftereffect to the left hand (after). One sees that aftereffects develop during training with the right hand that do not transfer to the left hand. The bar plot shows the mean initial angular deviation across subjects (±1 SE). B, Control 2. Intralimb transfer of learning is observed in the gradual-training condition. The figure shows limb configurations and movement directions that were used in the two intralimb transfer tests, along with hand paths for each of the four control subjects (c1 to c4). Dashed lines show hand paths that correspond to force-field catch trials during the familiarization phase; solid lines show the first trial of each intralimb transfer test.
- Figure 2.
Transfer of learning to the left hand is not observed when the load is applied gradually. There is partial transfer of learning in the abrupt condition. A, Movements of the left hand for single subjects. Dashed lines show hand paths for force-field catch trials that were interspersed during the familiarization phase before training. Solid lines show hand paths in the first trial of the transfer tests. Subjects s1 to s4 were from groups 1 to 4 (Table 1). B, Initial angular deviation averaged (mean ± 1 SE) in each trial of the transfer tests. The bar plots show the mean over subjects of the two force-field catch trials that were introduced during the familiarization phase and the mean (±1 SE) of the first test trials. The plot gives the first trial of the transfer test for the experimental group and, for the group of naive subjects, the first test trial with the left hand in the force field. deg., Degree; dev., deviation.
Tables
First training Second Training Group Condition Target Condition Target 1 Abrupt 1 Gradual 2 2 Gradual 2 Abrupt 1 3 Abrupt 2 Gradual 1 4 Gradual 1 Abrupt 2 -
Subjects were divided into two groups: six subjects first trained in the abrupt, and then in the gradual condition; the order of training was reversed for the other subjects. In each group, three subjects moved to target 1 in the abrupt training condition and to target 2 during the gradual training condition. Movement directions were reversed for the other subgroup.
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