Originally posted October 1, 2018
Here is an excerpt:
Philosophers have wrestled with questions of free will—that is, whether we are active drivers or passive observers of our decisions—for millennia. Neuroscientists tap-dance around it, asking instead why most of us feel like we have free will. They do this by looking at rare cases in which people seem to have lost it.
Patients with both alien limb syndrome and akinetic mutism have lesions in their brains, but there doesn’t seem to be a consistent pattern. So Darby and his colleagues turned to a relatively new technique known as lesion network mapping.
They combed the literature for brain imaging studies of both types of patients and mapped out all of their reported brain lesions. Then they plotted those lesions onto maps of brain regions that reliably activate together at the same time, better known as brain networks. Although the individual lesions in patients with the rare movement disorders appeared to occur without rhyme or reason, the team found, those seemingly arbitrary locations fell within distinct brain networks.
The researchers compared their results with those from people who lost some voluntary movement after receiving temporary brain stimulation, which uses low-voltage electrodes or targeted magnetic fields to temporarily “knock offline” brain regions.
The networks that caused loss of voluntary movement or agency in those studies matched Darby and colleagues’ new lesion networks. This suggests these networks are involved in voluntary movement and the perception that we’re in control of, and responsible for, our actions, the researchers report today in the Proceedings of the National Academy of Sciences.
The info is here.