Researchers Explain Mechanism Behind Brain Stimulation Using Electricity

A team of researchers has finally describe how stimulating a single region of the brain via electricity affects the activation of other regions and large-scale activity within the brain.

Their discovery, described in a paper published in the journal PLOS Computational Biology, showed that stimulating areas of the brain called "Network Hub" could result to the global activation of many brain regions.

"The question we asked in this study was how much of the brain is activated by stimulating a single region," explained Danielle S. Bassett, Ph.D., Eduardo D. Glandt Faculty Fellow and associate professor of bioengineering in the University of Pennsylvania School of Engineering and Applied Science and one of the authors of the study, in a statement. "We found that some regions have the ability to steer the brain into a variety of states very easily when stimulated, while other regions have less of an effect."

For the study, the researchers scanned the brain of eight individuals using MRI. The image of the participants' brain was then used to map the  brain architecture. Using a computational model to stimulate brain activity, the researchers were able to examine the impact of stimulation to each of the 83 regions of the brain.

The researchers observed that regions of the brain that are in the so-called "network hubs', areas of the brain that are strongly connected to other parts of the brain through the brain's white matter, have what they call "high functional effect". This means that stimulating these regions could result to global activation of many brain regions.

In particular, regions in the subcortical network, which is composed of regions that evolved relatively early on and are critical for emotion processing, could bring global changes in the brain when stimulated. Additionally, stimulating regions in the default mode network, which is composed of regions that evolved later and are critical for self-referential processing when a person is at rest, or not completing any task, could also lead to surplus of new brain states.

However, some regions in the more weakly connected areas in the brain, such as in the sensory and association cortex, produced limited effect in the brain activity when stimulated.

With these findings, researchers could offer two types of brain stimulation therapies. It could be a broad reset that alters the global dynamics of the brain or a more targeted approach that only alters the dynamics of some regions.