Theta band activity during physical exercise correlates with memory improvement

It has been shown that physical exercise is beneficial for cognition, however, the neuronal mechanism underpinning this process is not yet clear. In a study examining the immediate effects of physical exercise on long-term memory, we aimed to investigate the correlation of brain activity during physical exercise with memory performance. Healthy adult participants (n = 18) were asked to memorise a set of 80 stimuli. Subsequently, they were asked either to cycle on an exercise bike for ~30 minutes (2 minutes of warm-up + 6 blocks of 4-minute cycling 1-minute rest) while their EEG was recorded, or to sit on the exercise bike comfortably and watch a documentary for 30 minutes. After a 1.5 hour retention interval period, they were shown 160 stimuli (80 old and 80 new) and were asked to perform an old/new recognition task. The behavioural data showed an improvement in memory performance (exercise 71.11% vs. rest 66.67%, p=0.02). More importantly, the theta band oscillatory activity of an electrode over the dorsolateral prefrontal cortex (DLPFC) was negatively correlated with the enhanced performance (r=-0.48, p=0.04). Results highlight the modulatory effect of physical exercise on neuronal activity and a functional role of theta activity in memory enhancement during consolidation.