Degree of handedness affects intermanual transfer of skill learning

Visuomotor adaptive improvement and aftereffects are impaired differentially following cerebellar lesions in SCA and PICA territory

The aim of the present study was to elucidate the contribution of the superior and posterior inferior cerebellum to adaptive improvement and aftereffects in a visuomotor adaptation task. Nine patients with ischemic lesions within the territory of the posterior inferior cerebellar artery (PICA), six patients with ischemic lesions within the territory of the superior cerebellar artery (SCA) and 17 age-matched controls participated. All subjects performed center-out reaching movements under 60° rotation of visual feedback. For the assessment of aftereffects, we tested retention of adaptation and de-adaptation under 0° visual rotation. From this data we also quantified five measures of motor performance. Cerebellar lesion-symptom mapping was performed using magnetic resonance imaging subtraction analysis. Adaptive improvement during 60° rotation was significantly degraded in PICA patients and even more in SCA patients. Subtraction analysis revealed that posterior (Crus I) as well as anterior cerebellar regions (lobule V) showed a common overlap related to deficits in adaptive improvement. However, for aftereffect measures as well as for motor performance variables only SCA patients, but not PICA patients showed significant differences to control subjects. Subtraction analysis showed that affection of lobules V and VI were more common in patients with impaired retention and de-adaptation, respectively. Data shows that areas both within the superior and posterior inferior cerebellum are involved in adaptive improvement. However, only the superior cerebellum including lobules V and VI appears to be important for aftereffects and therefore true adaptive ability.

Effect of drawing hand and age on figural fluency: a graphomotor study with the five-point test in children

The aim of the study was to assess conceptual thinking in children in relation to age and motor dominance. We investigated the effect of the right and the left hand in a fluency task in four groups of 127 healthy right-handed children (age 5-12 years) and an adult control group. They performed the Five-Point Test twice, once with their dominant right and once with their nondominant left hand. The number of items and errors were analyzed with respect to age, drawing hand, and motor transfer. The performance of boys and girls did not differ. There was a significant effect for age and a prominent interaction between age, hand, and order (right hand or left hand first). Performance improved linearly with age. The dominant right hand performed generally better and there was a learning effect for both hands, but there was a learning advantage for the dominant hand, which increased with age. The influence of motor dominance in this fluency task seems to establish before conceptual maturity (around age 7, respectively 9 to 10).