Does healthy aging affect the hemispheric activation balance during paced index-to-thumb opposition task?
Naccarato M; Calautti C; Jones PS; Day DJ; Carpenter TA; Baron JC Department of Clinical Neurosciences, University of Cambridge, Addenbrooke’s Hospital, Box 83, Cambridge CB2 2QQ, UK. Normal aging is generally associated with declining performance in cognitive and fine motor tasks. Previous functional imaging studies have been inconsistent regarding the effect of aging on primary motor cortex (M1) activation during finger movement, showing increased, unchanged or decreased activation contralaterally, and more consistently increased activation ipsilaterally. Furthermore, no study has addressed the effect of age on M1 hemispheric activation balance. We studied 18 optimally healthy right-handed subjects, age range 18-79 years (mean +/- SD: 47 +/- 17) using 3 T fMRI and right index finger-thumb tapping auditory-paced at 1.25 Hz. The weighted Laterality Index (wLI) for M1 was obtained according to Fernandez et al. (2001) [Fernandez, G., de Greiff, A., von Oertzen, J., Reuber, M., Lun, S., K
