This time around, I had better luck locating an article…
By reading only the abstract, it looks to me like Desmurget et al, used electrical stimulation in seven patients undergoing awake brain surgery.
That is indeed so. He points out that the philosophical/religious idea that intention arises in some non-physical spiritual domain and uses the physical brain as a tool to realise the action has been increasingly challenged by the evidence:
“A central question in the study of human behavior concerns the origin of willed actions. Where in the brain are intentions formed? How do we become aware of these intentions? According to the dualist philosophy (
1), our encephalon is just the recipient of conscious intentions formed elsewhere in a nonphysical realm. This implies that conscious intention comes first, as the leading cause of our actions. Although appealing from a spiritual point of view, this hypothesis was progressively challenged by a large set of studies (
2–
4). Results showing that the decision to move did not precede, but instead lagged, the onset of brain activity signaling motor preparedness were especially convincing (
5–
7). Thus, researchers suggested that conscious intention of a movement emerged as a consequence of increased neural activity in a premotor-parietal circuit, which elaborates motor plans before action.”
The problem then becomes identifying the specific neural circuit which gives rise to the experience of free-will and intention, which he addresses in this paper. To cut a long story short, stimulation of specific regions of the pre-motor regions causes movement without the experience of an intention to move (or indeed an awareness of movement), while stimulation of specific regions of the inferior parietal regions created an intention to move and with a higher intensity of stimulation, a belief that movement had occurred, even if it hadn’t. Their conclusion:
“Our study suggests that 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.”
See also: “The Volitional Brain; Towards a neuroscience of free will”, ed Libet et al, Imprint Academic, ISBN 1355 8250 (1999).
Also, the Journal of Consciousness Studies (which sponsored the above book) is a very prestigious journal covering physics, biology, neurobiology, philosophical and social aspects of the study of human consciousness. See, for example Haggard and Johnson, Experiences of Voluntary Action,
J Consciousness Studies 10, 72 - 84 (2003)
Alec
evolutionpages.com