Article

Unconscious determinants of free decisions in the human brain. Nat Neurosci

Ghent Institute for Functional and Metabolic Imaging of the brain, Ghent University, Gand, Flanders, Belgium
Nature Neuroscience (Impact Factor: 16.1). 06/2008; 11(5):543-5. DOI: 10.1038/nn.2112
Source: PubMed

ABSTRACT

There has been a long controversy as to whether subjectively 'free' decisions are determined by brain activity ahead of time. We found that the outcome of a decision can be encoded in brain activity of prefrontal and parietal cortex up to 10 s before it enters awareness. This delay presumably reflects the operation of a network of high-level control areas that begin to prepare an upcoming decision long before it enters awareness.

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Available from: Chun Siong Soon
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    • "Because this readiness potential must detach from the rest of cognition, it is no longer integrated. For example, following up on Libet's original experiments, Soon et al. (2008) demonstrated that, by monitoring activity in the frontopolar prefrontal cortex, they could predict a participant's decision to move their right or left hand several seconds before the participant became aware of it. However, assuming people's behaviour is irreversibly integrated, then somewhere between the stimulus entering the brain and a decision to act leaving the brain, there must be a point where the information cannot be fully disentangled from the rest of cognition. "
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    • "The neural preparatory processes for action run from activity in higher cognitive areas to lower cognitive areas. dMPFC dorsomedial prefrontal cortex, RCZ rostral cingulate zone, SMA supplementary motor area, RP readiness potential, ERD eventrelated desynchronization Soon et al. 2008 ). The current study suggests that the process of intending develops during the process of acting, leaving traces in consciousness at certain points along the road, ultimately reaching awareness and becoming reportable . "
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    • "It has also been observed in more complex tasks, such as viewing the Rubin's vase-face picture, where not just whether a stimulus is perceived but how it is perceived is determined by the prestimulus activity state (Hesselmann et al., 2008a). Finally, intrinsic activity fluctuations have also been linked to behaviour in a free-decision button press task (Soon et al., 2008 ). In this, intrinsic activity was found to predict what response the participant was going to make before they were aware of making the decision as to which button to press and pressing it. "
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