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Written by: Emily Rehmet Edited by: Ethan Thio  The rise of neuroscientific data has continued to shape our understanding of the ways in which our mind retrieves, processes, and conveys information about the world around us. New neuroscientific research has shed additional light on a hotly debated topic — free will. Free will is a perception of control — the feeling that we are in command of our actions, desires, and decisions. Developments in neuroscience have led to the general conclusion that because individual action is strictly the result of brain functions, that we must not have “free will” or agency over our decisions. Despite the rise of free will skeptics, the question remains, why do humans “feel” like we have free will? How is this produced in the brain? Neuroscientists may have recently found a crucial piece in the part of this puzzle. Ryan Darby, Juho Joutsa, Matthew Burke, and Michael Fox conducted a brain lesion study in order to find the brain region where our perception of “free will” originates [1]. To do this, they identified brain-lesioned patients with dysfunctions to their perception of “free will,” specifically those who have lost the desire to act (a condition called akinetic mutism) and also those who have lost a sense of responsibility for their actions (a condition called alien limb syndrome). According to the authors, these two components, volition and agency, together compose our perception of free will. Because these patients lack volition or agency, the scientists sought to compare their brain function to unaffected individuals to conclude the differences stemming from the sense of free will. When Darby et al. (2018) used the literature to compare patients with brain damage causing akinetic mutism, they found that the affected brain regions varied wildly. This was also found to be the case with patients with alien limb syndrome. Because of this variation in brain region/lesion localization, Darby et al. (2018) used a novel technique called lesion network mapping to determine if these lesions locations were localized to a specific brain network, rather than a specific region of the brain/lesion. This technique allowed the researchers to discover that lesions related to alien limb syndrome were actually located in a specific network within the brain, specifically through connectivity to the precuneus region of the brain. The precuneus region, located in the central-back of the parietal lobe, is involved in sixty known complex functions, including memory retrieval, integration of information, perception, along with other purposes [2]. Additionally, lesion locations causing akinetic mutism also were localized to a specific network involving the anterior cingulate cortex of the brain. The anterior cingulate cortex has been implicated in complex cognitive roles such as emotional learning, assessing motivation, and motor functionality, a structure which wraps around the back side of the corpus callosum (a white matter structure connecting the two hemispheres of the brain) [3]. After cross-checking these results with a different group of patients with psychiatric conditions affecting these same brain networks (and finding that they also have deficits in their perception of free will), Darby et al. concluded that the anterior cingulate cortex and precuneus regions are implicated in our perceptions of free will. These results do not provide conclusive evidence towards where exactly our sense of free will is found in the brain, though it does shed some additional light on the brain networks involved in this undeniably complex process. Ideally, this research will be just a stepping stone to allow us to more deeply examine free will — one of the most personal elements of human perception, fundamental to our sense of self. Works Cited:
[1] Darby RR, Joutsa J, Burke MJ, Fox MD. Lesion network localization of free will [Internet]. Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences; 2018 [cited 2020Feb24]. Available from: https://www.ncbi.nlm.nih.gov/pubmed/30275309 [2] Cavanna AE, Trimble MR. The precuneus: a review of its functional anatomy and behavioural correlates. Brain. 2006Jun;129(3):564–83. [3] Devinsky O, Morrell MJ, Vogt BA. Contributions of anterior cingulate cortex to behaviour. Brain. 1995;118(1):279–306. [4] Pixabay [Internet]. Pixabay. Available from: https://pixabay.com/illustrations/brain-wave-awareness-compassion-4372153/
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