Physical activity, especially cardiovascular fitness training, has been shown to enhance cognitive performance and to counteract age-related cognitive decline Furthermore, regular physical activity has been demonstrated to diminish age-related volume-shrinkage in several brain regions particularly in the prefrontal cortex and hippocampus In the same vein, physical activity and high levels of cardiovascular fitness seem to enhance neurocognition during childhood In this context, the basal ganglia and its components, the caudate nucleus, the putamen and the globus pallidus, are of special interest as animal research indicates that exercise also seems to influence the molecular architecture and the metabolic capacity of the basal ganglia 14, Besides their fundamental role in motor execution 16 , the basal ganglia are also involved in many cognitive functions like mental flexibility 17 , task-switching ability 18 and cognitive control The striatum is the input nucleus of the basal ganglia and is composed of caudate nucleus and putamen.
The pars interna of the globus pallidus is together with the substantia nigra pars reticulata the output region of the basal ganglia and conveys information from the striatum to the thalamus and back to the frontal areas The striatum, which is essential for cognitive flexibility and attentional control, shows an increase during childhood and adolescence 23,24 and a particularly rapid and early age-related change 9,25 in older adults.
Furthermore, the described cognitive functions are essential for academic success of children and young adults. In this review, we will summarize research that investigated whether physical activity has the potential to be such an intervention.
First, we will show that neuroplasticity in the basal ganglia is possible in principle. Second, we will report studies where the relationship between physical fitness level and volume of the basal ganglia and its relation to cognitive performance were investigated. Besides cross-sectional studies, we will report studies that investigated exercise-induced changes in the volume of the basal ganglia and related changes in cognitive performance after long-term fitness interventions.
The basal ganglia are, prospectively, positively influenced by physical activity because animal research indicated that cardiovascular exercise does not only seem to influence angiogenesis, synaptogenesis and the release of growth hormones in motor cortex 26 , cerebellum 27 and hippocampus 28,29 , but also in the basal ganglia Furthermore, the striatum is the second region โ besides the hippocampus โ where neurogenesis in humans has been proven 30, Plasticity of basal ganglia has been proven in motor learning studies.
