Preview

PDF 393Kb

Neural interactions between contralateral motor regions are thought to be instrumental in the successful preparation, and execution, of volitional movements. Here we investigated whether healthy ageing is associated with a change in functional connectivity, as indicated by the ability to modulate interhemispheric interactions during movement preparation in a manner that assists rapid movement responses. Thirteen young (mean age 22.2 years) and thirteen older (68.5 years) adults rapidly abducted their left index finger as soon as possible in response to a visual imperative signal, presented 500 ms after a visual warning signal. Interactions between left dorsal premotor cortex (LPMd) and right primary motor cortex (RM1) and between left primary motor cortex (LM1) and RM1 were investigated at six time points between the warning signal and the volitional response using paired-pulse transcranial magnetic stimulation. Relative to the inhibitory interactions measured at rest, both young and older adults released LM1-RM1 inhibition beginning 250 ms after the warning signal, with no significant differences between groups. LPMd-RM1 interactions became facilitatory (from the onset of the imperative signal onwards) in the older, but not the young, group. Regression analyses revealed that for the older adults, modulation of LPMd-RM1 interactions early in the preparation period was associated with faster responses, suggesting that specifically timed modulation of these pathways may be a compensatory mechanism to offset, at least in part, slowing of motor responses. The results suggest a greater reliance on premotor regions during the preparation of simple motor actions with advancing age.

Item Type:	Refereed Article
Research Division:	Psychology
Research Group:	Cognitive and computational psychology
Research Field:	Sensory processes, perception and performance
Objective Division:	Health
Objective Group:	Specific population health (excl. Indigenous health)
Objective Field:	Health related to ageing
UTAS Author:	Hinder, MR (Associate Professor Mark Hinder)
UTAS Author:	Fujiyama, H (Dr Hakuei Fujiyama)
UTAS Author:	Summers, JJ (Professor Jeffery Summers)
ID Code:	81681
Year Published:	2012
Web of Science® Times Cited:	37
Deposited By:	Psychology
Deposited On:	2012-12-20
Last Modified:	2017-11-05
Downloads:	349 View Download Statistics