Systems Neuroplasticity in the Aging Brain: Recruiting Additional Neural Resources for Successful Motor Performance in Elderly Persons

Abstract

Functional imaging studies have shown that seniors exhibit more elaborate brain activation than younger controls while performing motor tasks. Here, we investigated whether this age-related overactivation reflects compensation or dedifferentiation mechanisms. "Compensation" refers to additional activation that counteracts age-related decline of brain function and supports successful performance, whereas "dedifferentiation" reflects age-related difficulties in recruiting specialized neural mechanisms and is not relevant to task performance. To test these predictions, performance on a complex interlimb coordination task was correlated with brain activation. Findings revealed that coordination resulted in activation of classical motor coordination regions, but also higher-level sensorimotor regions, and frontal regions in the elderly. Interestingly, a positive correlation between activation level in these latter regions and motor performance was observed in the elderly. This performance enhancing additional recruitment is consistent with the compensation hypothesis and characterizes neuroplasticity at the systems level in the aging brain.

Ageing of internal models: from a continuous to an intermittent proprioceptive control of movement

“…Indeed, recent studies showed that older adults could reach levels of motor performance comparable to those obtained in young adults. However, to reach such levels of performance, older adults had to recruit additional attentional and cortical resources which could be interpreted as a compensating mechanism (Boisgontier et al 2012;Goble et al 2010a, b;Heuninckx et al 2004Heuninckx et al , 2005Heuninckx et al , 2008Hutchinson et al 2002;Mattay et al 2002;Naccarato et al 2006). This additional recruitment reduced the remaining attentional and cortical resources as evidenced by a degraded behavioural performance in older adults when the task complexity increased (Boisgontier et al 2012;Goble et al 2012b;Heuninckx et al 2004;Seidler et al 2002).…”

“…It was hypothesised that (1) the ability to accurately match the proprioceptive target in the self-selected speed condition was not different between young and older adults. Indeed, although it was against an increased cognitive cost and additional neural resources, previous studies showed that older adults were able to reach levels of proprioceptive control of movement comparable to those of young adults (Batavia et al 1999;Boisgontier et al 2012;Deshpande et al 2003;Goble et al 2012a, b;Heuninckx et al 2008;Marks 1996;Pickard et al 2003). However, on the basis of the differences observed in motor imagery (Personnier et al 2010(Personnier et al , 2008Skoura et al 2005) and kinematic studies (Elliott and Hansen 2010;Goggin and Meeuwsen 1992;ReyRobert et al 2012; Seidler-Dobrin and Stelmach 1998), we hypothesised that (2) older adults were not able to reach the same level of end-point performance as the young adults in the fast speed condition due to the temporal constraints, making it impossible to use additional sub-movements to compensate for the presumably altered internal models.…”

Interference of action perception on action production increases across the adult life span

“…The activity of this system is shown to change with age (Sharma & Baron, 2014;Ward, 2006;Ward & Frackowiak, 2003), which is associated with a decrease of action perception (e.g., accuracy of action prediction, Diersch et al, 2012) and action production (e.g., greater movement variability and deficits in coordination, Seidler et al, 2010). Furthermore, older adults compared to younger adults show activation in additional brain areas during movement execution, coordination and action perception (Diersch et al, 2016;Heuninckx et al, 2005;Heuninckx, Wenderoth, & Swinnen, 2008. As age advances, action perception and production might be increasingly associated with the activation of motor programs that are irrelevant for the on-going task.…”

Visuomotor behaviors in computer-based reaching tasks by young and older adults: implication for geriatric rehabilitation

“…However, when participants were adapted to the visual stimuli, the accumulation of explicit knowledge reduced progressively and therefore the potential problem of excessive perceptive load may be solved. On the other hand, the effects of ageing change visual information acquirement during movements execution process, which correspondingly leads to distinct gaze behaviors [42]. Older adults shrink the area of space to extract useful visual information and this may be partly compensated by the illicit saccades.…”