Main Points
Where in the brain are intentions and willed actions formed?
How do we become aware of these intentions?
Stimulation of the posterior parietal cortex caused human participants to intend to move and to report having moved, even in the absence of actual motor responses.
Stimulation of the premotor cortex triggered limb and mouth movements that weren’t consciously detected by the patients
Motor intention and awareness are emerging consequences of increased parietal activity before movement execution.
The subjective (and potentially illusory) feeling that we are executing a movement does not arise from movement itself, but it is generated by prior conscious intention and its predicted consequences.
Methods
Got formal consent from informed patients (with lesions) to perform the procedure
Direct electrical stimulation under local anesthesia on patients
Surgeon informed patient that a stimulation was about to start
Surgeon counted out loud to let patient and experimenter know the onset and end of stimulation
Experimenter asked patient whether he/she felt something or moved Other stimulations were done to determine areas potentially eloquent for movement and language
Coordinates of stimulation sites were recorded
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