AGING AND MOTOR INHIBITION: A CONVERGING PERSPECTIVE PROVIDED BY BRAIN STIMULATION AND IMAGING APPROACHES
Oron Levin
KU Leuven Movement Control and Neuroplasticity Research Group, Department of Kinesiology,
Group Biomedical Sciences, Leuven, Belgium
Age-related changes in brain function may be triggered by localized structural alterations that occur in brain grey and white matter structure characterized by neuronal atrophy, leading to impaired activation of several neurotransmitter systems such as gamma-aminobutyric acid (GABA), Glutamate and Dopamine; phenomena that held responsible for less effective inhibitory control. Evidence for linking poor intra- and inter-hemispheric inhibition with declined motor control has become available with the use of noninvasive neuroimaging and brain stimulation techniques. Specifically, observations suggest that successful performance of a motor task in older adults is related, partly, to the capacity to modulate inhibition through the GABAA and GABAB receptor-mediated neurotransmission systems. As a decline in the integrity of the GABAergic inhibitory processes may emerge due to age-related loss of white and gray matter, a promising direction for future research would be underscoring relationships between declines in the inhibitory control of movements and other biomarkers of aging which reflect changes in structural, biochemical and functional brain metrics.
For a brain to function optimally, it is not only required that each brain area fulfills its information processing role but also that information is exchanged between areas via short- and long-range white matter tracts that secure interregional interactions. Changes in brain structural and neurochemical properties are expected to interrupt functional communication between substructures of the brain’s (inhibitory) network which ultimately give rise to age-related declines in (motor) behavior. Nonetheless, the boundaries and structure of the brain network that regulate inhibition are not fully acknowledged and some substructures of this network (e.g., the prefrontal network) are more prone to the aging process than others. In the present talk I aim, specifically, to point at the missing part of the puzzle and discuss a multimodal approach that could shed light on the neurological mechanisms underlying impaired inhibitory control in healthy aging.
