Greater Intermanual Transfer in the Elderly Suggests Age-Related Bilateral Motor Cortex Activation Is Compensatory

Abstract

ABSTRACT. Hemispheric lateralization of movement control diminishes with age; whether this is compensatory or maladaptive is debated. The authors hypothesized that if compensatory, bilateral activation would lead to greater intermanual transfer in older subjects learning tasks that activate the cortex unilaterally in young adults. They studied 10 young and 14 older subjects, learning a unimanual visuomotor task comprising a feedforward phase, where there is unilateral cortical activation in young adults, and a feedback phase, which activates the cortex bilaterally in both age groups. Increased intermanual transfer was demonstrated in older subjects during feedforward learning, with no difference between groups during feedback learning. This finding is consistent with bilateral cortical activation being compensatory to maintain performance despite declining computational efficiency in neural networks.

Keywords:

• intermanual transfer
• aging
• HAROLD model
• CRUNCH model

ACKNOWLEDGMENTS

The authors thank all the participants for their helpful collaboration. Sara Graziadio and Kianoush Nazarpour contributed equally to this article.

FUNDING

The authors gratefully acknowledge financial support from Wellcome Trust and the Medical Research Council.