- In “The Cognitive Way to Action,” Marc Jeannerod describes research on the generation of voluntary action. He begins with an historical overview of theories in the field. Already in the 1930s researchers noted that even the simplest movements produced by the nervous system of a frog appeared to be organized purposefully. So the question was, How are these actions represented in the brain? An important advance was the recognition that behavior is guided by internal models of the external world, with predictions built in as to how the external world will be modified by the organism’s behavior and how the organism itself will be affected by the action. The existence of such models is supported by ethological studies showing that certain behavioral sequences unfold blindly and eventually reach their goal after they have been triggered by external cues. Localized brain stimulation can also trigger similarly complex actions.
- Early accounts hypothesized serial steps in the neural generation of actions. However, current brain studies suggest simultaneous activation in cortical and subcortical levels of the motor system. This distributed model of action-generation raises the issue of a central coordinator to determine the temporal structure of the motor output. The behavior of patients with damage to the frontal lobes suggests to Jeannerod that the supervisor system is associated with this region.
- New light is now being shed on the problem of the neural substrates of action-generation by the study of mentally-simulation action. Jeannerod and his colleagues instructed subjects to imagine themselves grasping objects. Using Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI), they identified the cortical and subcortical areas involved. They were then able to show that forming the mental image of an action produces a pattern of cortical activation that resembles that involved in intentionally executing the action.
- Jeannerod expects research such as this to shed light on the neural underpinnings of central aspects of the self such as intentionality and self-consciousness1. He notes that there is now neuropsychological evidence for the moral dictum that “to intend is to act.”
University of Notre Dame Press; 1st edition (28 Feb 2000); Abstract from Link.
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