Cardiovascular fitness modulates brain activation associated with spatial learning

Abstract

Aerobic exercise has beneficial effects on cognitive functioning in aging humans, especially on executive functions associated with frontal brain regions. In rodents, exercise has been shown to induce structural and neurophysiological changes especially in the hippocampus and to improve spatial learning. The present study investigated the relationship between cardiovascular fitness, spatial learning and associated patterns of brain activation cross-sectionally and longitudinally in a sample of middle-aged men and women (40-55 years) that took part in a six-month exercise intervention and an additional spatial training. Spatial learning capacities before and after the interventions were measured with a virtual maze task. During this task, participants were repeatedly moved through a virtual town and were instructed to infer the spatial layout of the environment. Brain activations during encoding of the virtual town were assessed with functional magnetic resonance imaging (fMRI). The fMRI data revealed that brain activations during successful spatial learning were modulated by the individual fitness level in a neural network, comprising the hippocampus, retrosplenial cortex, cuneus, precuneus, parahippocampal gyrus, caudate nucleus, insula, putamen, and further frontal, temporal, occipital and cingulate regions. Moreover, physical exercising induced changes in cardiovascular fitness that correlated positively with changes in brain activations in the medial frontal gyrus and the cuneus. However, overall spatial learning performance did not vary with cardiovascular fitness. These data suggest that cardiovascular fitness has an impact on brain regions associated with spatial learning in humans and hence, could be a potent intervention to prevent age-related cognitive decline.