Acute aerobic exercise enhances attentional modulation of somatosensory event-related potentials during a tactile discrimination task

Neuroimaging research has shown that acute bouts of moderate intensity aerobic exercise can enhance attention-based neuronal activity in frontal brain regions, namely in the prefrontal cortex (PFC), as well as improve cognitive performance. The circuitry of the PFC is complex with extensive reciprocal corticocortical and thalamocortical connections, yet it remains unclear if aerobic exercise can also assist attentional control over modality-specific sensory cortices. To test this, we used a tactile discrimination task to compare tactile event-related potentials (ERPs) prior to and following an acute bout of moderate intensity aerobic exercise. We hypothesized that exercise preceding performance of the task would result in more efficient sensory gating of irrelevant/non-attended and enhancement of relevant/attended sensory information, respectively. Participants received vibrotactile stimulation to the second and fifth digit on the left hand and reported target stimuli on one digit only. ERP amplitudes for the P50, P100, N140 and long latency positivity (LLP) were quantified for attended and non-attended trials at FC4, C4, CP4 and P4 while P300 amplitudes were quantified in response to attended target stimuli at electrodes FCZ, CZ and CPZ. Results showed no effect of attention on the P50, however, both P100 and LLP amplitudes were significantly greater during attended, task-relevant trials, while the N140 was enhanced for non-attended, task-irrelevant stimuli. Moreover, unattended N140 amplitudes over parietal sites contralateral to stimulation were significantly greater post-exercise versus pre-exercise, while LLP modulation varied with greater unattended amplitudes post-exercise over frontal sites and greater attended amplitudes post-exercise over parietal sites. These results suggest that a single session of moderate intensity aerobic exercise facilitated the sensory gating of task-irrelevant tactile stimuli so that relevant sensory signals could be enhanced at later stages of somatosensory processing in healthy young adults.