Altered awareness of voluntary action after damage to the parietal cortex

Nat Neurosci. 2004 Jan;7(1):80-4. doi: 10.1038/nn1160. Epub 2003 Nov 30.


A central question in the study of human behavior is the origin of willed action. EEG recordings of surface brain activity from human subjects performing a self-initiated movement show that the subjective experience of wanting to move follows, rather than precedes, the 'readiness potential'--an electrophysiological mark of motor preparation. This raises the issue of how conscious experience of willed action is generated. Here we show that patients with parietal lesions can report when they started moving, but not when they first became aware of their intention to move. This stands in contrast with the performance of cerebellar patients who behaved as normal subjects. We thus propose that when a movement is planned, activity in the parietal cortex, as part of a cortico-cortical sensorimotor processing loop, generates a predictive internal model of the upcoming movement. This model might form the neural correlate of motor awareness.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Analysis of Variance
  • Awareness / physiology*
  • Cerebellar Diseases / physiopathology
  • Consciousness Disorders / physiopathology*
  • Electroencephalography / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Parietal Lobe / physiology*
  • Parietal Lobe / physiopathology*
  • Psychomotor Performance / physiology*