Experts at Vanderbilt University Medical Center have investigated the brain networks involved in free will using a new technique known as lesion network mapping. The study revealed that all brain activity related to the power to act, or volition, falls within the same brain network.
The experts teamed up with researchers from Harvard Medical School to analyze cases of akinetic mutism, patients who lack the motivation to move or speak, and alien limb syndrome, which is when patients feel that their movement is generated by someone else.
The study revealed that even though injuries disrupting volition can occur in many different locations, they are still part of the same brain network. Furthermore, injuries that disrupt agency, or a feeling of responsibility for carrying out those actions, fall within a separate network.
Dr. Ryan Darby is an assistant professor of Neurology at Vanderbilt and the lead author of the study.
“Our approach challenges the assumption that neuropsychiatric symptoms should localize to one brain region, and instead shows that these symptoms localized to interconnected brain networks,” said Dr. Darby. “Once we understand that agency and volition localize to brain networks, can we then take that knowledge and develop a new approach to treating a symptom?”
The researchers concluded that stimulation in different parts of brain networks could change free will perception.
The team also studied psychiatric patients with disrupted free will, including motor conversion disorder and catatonia. These psychiatric patients had neuroimaging abnormalities in brain networks associated with volition and agency.
“There are very few approaches where you can compare a similar type of symptom in a neurological patient and a psychiatric patient,” said Dr. Darby. “Our study shows the promise of using our network localization method in neurological patients to better understand symptoms in psychiatric patients. That being said, it’s the first time we have used our technique with neuroimaging abnormalities in psychiatric patients. It would require further study and validation, but I think the promise is there.”
The study is published in the Proceedings of the National Academy of Sciences.
By Chrissy Sexton, Earth.com Staff Writer