Cardiorespiratory fitness and cognitive and brain plasticity in older adults
The critical importance of the environment on behavior, brain structure and function, can be traced back to the work of Donald O. Hebb (1947), who observed rats raised as pets to engage creatively in problem-solving behavior, as opposed to caged rats. This seminal study, introduced the era of “environment enrichment,” where through many distinctive, and innovative animal studies, scientists empirically demonstrated the prophylactic influence of a rich, complex environment on the learning and brain health of rats. Extending this work to humans, recent research provides additional evidence of superior psychomotor abilities of athletes, as well as an increase in executive control abilities of older adults. In this talk, the neural correlates associated with this increased cognitive flexibility in older adults as a function of increasing levels of cardiorespiratory fitness are discussed. Employing a version of the Stroop task, we examined whether higher levels of cardiorespiratory fitness were associated with an increase in activation in cortical regions responsible for imposing attentional control along with an up-regulation of activity in sensory brain regions that process task-relevant representations. Higher fitness levels were associated with better behavioral performance and an increase in the recruitment of prefrontal and parietal cortices in the most challenging condition, thus providing evidence that cardiorespiratory fitness is associated with an increase in the recruitment of the anterior processing regions. There was a top-down modulation of extrastriate visual areas that process both task-relevant and task-irrelevant attributes relative to the baseline. However, fitness was not associated with differential activation in the posterior processing regions, suggesting that fitness enhances attentional function by primarily influencing the neural circuitry of anterior cortical regions. This study provides evidence of a differential association of fitness with anterior and posterior brain regions, shedding further light onto the neural changes accompanying cardiorespiratory fitness.