Effect of electric brain stimulation and exercise on the blood brain barrier
“These findings give us new insights into how brain stimulation and exercise might influence our brains. It’s like discovering a new piece of the puzzle about how our brains respond to activity, which could help us understand more about how our brains function.”
BACKGROUND This study investigates the potential impact of electric brain stimulation and exercise on the blood-brain barrier. For those unfamiliar, the blood-brain-barrier (BBB) acts as a highly selective filter, controlling the entry of substances into the brain. Its primary role is to protect the brain from harmful molecules while allowing essential nutrients and molecules required for proper brain function to pass through. The BBB ensures optimal neural activity and protects against the intrusion of toxins and pathogens. Understanding the BBB is fundamental to comprehending brain function.
Researchers are looking at an alternative way to influence the BBB including transcranial direct current stimulation (tDCS) which involves applying a low electrical current to the brain. This technique has been used for various purposes, such as enhancing exercise performance and treating mental health conditions like depression and anxiety. Recent studies have looked at how tDCS affects the tiny blood vessels that make up the BBB. Some research in rats suggests that tDCS might increase the permeability of the BBB by affecting certain molecules and cells in the brain. While these findings are promising, more research is needed to understand how tDCS might impact the BBB in humans.
ABOUT THE STUDY In this study, we examined the impact of active tDCS, sham tDCS, and no stimulation on salivary levels of the protein S100B in 13 healthy adults. S100B serves as an indicator of BBB integrity. Saliva samples were collected before and after active tDCS, sham tDCS or no stimulation, and again after an endurance cycling task
KEY FINDINGS Contrary to expectations, the study revealed minimal changes in S100B levels following tDCS alone. The difference between our study in humans and previous rat studies may be attributed to differences in the applied electrical current and current density where the levels applied to rats are beyond the safety limits for the human brain.
There were also no combined effects of tDCS and exercise on BBB permeability observed in our study. However, there were indications that physical exertion from exercise might temporarily influence BBB function, as evidenced by alterations in S100B levels post-exercise. This is significant because it indicates that physical activity could directly affect how the brain interacts with the rest of the body. Understanding this relationship could help us learn more about how exercise impacts brain health and function.
FROM THE ARTICLE
The Effects of Transcranial Direct Current Stimulation and Exercise on Salivary S100B Protein Indicated Blood-Brain Barrier Permeability: A Pilot Study.
Journal of Neuromodulation, December 2023 https://doi.org/10.1016/j.neurom.2023.11.006
Aidan Lewis, Constantino Toufexis, Dr Chloe Goldsmith, Rebecca Robinson, Grace Howie, Dr Ben Rattray, Dr Andrew Flood