Neural correlates of the age-related changes in motor sequence learning and motor adaptation in older adults

Abstract

As the world's population ages, a deeper understanding of the relationship between aging and motor learning will become increasingly relevant in basic research and applied settings. In this context, this review aims to address the effects of age on motor sequence learning (MSL) and motor adaptation (MA) with respect to behavioral, neurological, and neuroimaging findings. Previous behavioral research investigating the influence of aging on motor learning has consistently reported the following results. First, the initial acquisition of motor sequences is not altered, except under conditions of increased task complexity. Second, older adults demonstrate deficits in motor sequence memory consolidation. And, third, although older adults demonstrate deficits during the exposure phase of MA paradigms, the aftereffects following removal of the sensorimotor perturbation are similar to young adults, suggesting that the adaptive ability of older adults is relatively intact. This paper will review the potential neural underpinnings of these behavioral results, with a particular emphasis on the influence of age-related dysfunctions in the cortico-striatal system on motor learning.

Keywords: adaptation; aging; cerebellum; consolidation; motor learning; neuroimaging; procedural memory; striatum.

Figure 1

Age-related volumetric declines in the (A) lateral prefrontal cortex and (B) caudate nucleus. Reprinted from Raz et al. (2005), by permission of Oxford University Press. Similar volumetric decreases are also evident in the putamen (Raz et al., 2003). (C) Transaxial planes at the level of the caudate nucleus depicting decreased dopaminergic activity (relative uptake of a dopamine D2-like receptor ligand) in a representative older subject compared to a young participant. Reprinted from Neuroscience and Biobehavioral Reviews, 26, Kaasinen and Rinne (2002), with permission from Elsevier. (D) FA values for three different white matter tracts in younger and older adults. Reprinted from Neurobiology of Aging, 32, (Bennett et al., 2011), with permission from Elsevier. ^*Significant age group differences (p < 0.01).