Modulations of Electroencephalography signals in Response to experimental pain During Single Leg Cycling exercise
Creators: name: Zadeh, Fatemeh Yousef
Publisher: name: Graduate Studies
Year: 2024
Subjects: subject: EEG
subject: contralateral pain
subject: occlusion pain
subject: Education--Health

description: Background: Exercise and health science researchers have been applying neuroimaging techniques such as electroencephalography (EEG) to elaborate on the brain's electrical activity and the cortical regions involved in the complex coordination of movements during exercise. Pain experienced during high-intensity exercise is an “inhibitory factor” that can alter the brain’s responses to exercise, reduce exercise tolerance, and limit the physiological and cognitive benefits of physical activity. Despite this evidence, there are few studies which have investigated the effect of muscle pain on the brain activity signals (recorded via EEG) during dynamic tasks such as cycling. Accordingly, this thesis explores the impact of submaximal single limb cycling and contralateral painful stimuli on the dynamics of alpha, beta, and gamma frequency bands EEG signals. Methods: Twenty-one healthy, recreationally active participants underwent two testing sessions. In the first visit, participants were familiarized with experimental protocol and performed a ramp incremental cycling test to determine peak power output. In the second visit, participants completed the following three experimental conditions while their EEG signals were captured during each task: (i) maintained a seated steady position while their visual gaze was kept on a printed circle (Fixation), (ii) completed a single-leg (SL) cycling task while the contralateral leg was maintained in resting state (Cycling), and (iii) completed the Cycling condition while a combination of electrical stimulation and blood flow occlusion (BFO) was used to induce pain the non-exercising leg (Pain). During all experimental conditions, pain and effort variables were recorded. Results: The experimental pain intervention induced a significant amount of pain (7.63±1.72 on the pain scale) in the contralateral leg. The overall EEG power for the alpha, beta and gamma bands showed reductions in both Cycling (p&lt;0.001) and Pain conditions (P&lt;0.001) when compared to the Fixation; however, there was no significant difference between the Cycling and Pain conditions (all P&gt;0.318). During Cycling, a considerable suppression of alpha power was observed, particularly for the two posterior locations (P &lt; 0.01). Discussion: Overall, these findings suggest that Cycling intervention can result in suppression of the three EEG frequency bands in posterior and anterior locations, however, superimposition of experimental pain on the contralateral leg may not augment this suppression in the Pain condition. It could be postulated that either pain stimulus in the present study was not adequate to modulate the EEG frequency signals or EEG spectral analysis is not a sensitive technique to detect additional pain stimulus-evoked in the contralateral resting leg. These findings lead us to the conclusion that further studies are required to investigate different levels of pain stimuli elicited during dynamic tasks on EEG spectral analysis to determine the sensitivity of the EEG technique to pain sensations perceived during exercise.