Joined: Oct. 2006
|Quote (keiths @ Jan. 03 2009,05:08)|
|Quote (Aardvark @ Jan. 03 2009,01:28)|
|From O'Leary's latest.|
|Neuroplasticity makes way more sense if your immaterial mind is real and directs your brain.|
How? Can anyone explain this?
Who knows? This is Denyse we're talking about, after all. My best guess is that she thinks that a purely physical brain would be inflexible, with a permanent, fixed mapping of functions to neurons. For her, there has to be something outside the brain telling it to remap a function to a different set of neurons.
I think she's so entrenched in her dualism that she literally cannot understand materialist arguments. They make no sense to her because she approaches them (unwittingly) with dualist assumptions that she cannot suspend, even for a moment, for the sake of understanding the materialist position.
Denyse's treatment in The Spatula Brain is brief and provides no guidance on this question:
|A central dogma of early neuroscience was that the neurons of the adult brain do not change. However, modern neuroscience now recognizes that the brain can reorganize (this reorganization is called "neuroplasticity") throughout life, not only in early childhood. Our brains rewire to create new connections, set out on new paths, and assume new roles.|
One outcome of the discovery of neuroplasticity was a reasonable explanation for the puzzling "phantom limb" syndrome. From the mid-nineteenth century onward, physicians have written - very cautiously to be sure - about the fact that amputees sometimes feel pain in a limb that no longer exists. The conventional suspicion was that either the doctor misinterpreted the symptoms or the amputee was seeking attention. However, V. S. Ramachandran showed that neurons that once received input from a vanished hand could rewire themselves to report input from the face. If an amputee's brain has not changed its mental map of the body after the amputation, she will experience those feelings as if they cam from her vanished hand (p. 103).
That is her entire treatment of neuroplasticity in The Spatula Brain. She provides no hint why it follows from the discovery that adult brains change more than originally believed - in response to other physical changes such as deafferentiation due to an amputation - that brain tissue is being pushed around by a detachable ghost as it functionally reorganizes. The actual rhetorical intent of this brief passage is instead to paint "materialist neuroscience" with the brush of "dogmatism":
|Overall, the few traditional simplicities in neuroscience are vanishing. The brain turns out to be more like an ocean than a clockwork (p. 103).|
It is always interesting to return to the literature when considering Denyse's writing. Ramachandran has posted his 1998 review from Brain, "The perception of phantom limbs: The D.O. Hebb lecture."
Denyse: "From the mid-nineteenth century onward, physicians have written - very cautiously to be sure - about the fact that amputees sometimes feel pain in a limb that no longer exists." (Note the specious insertion of the "persecution" theme so essential to her worldview.)
Ramachandran: "Phantom limbs were probably known since antiquity and, not surprisingly, there is an elaborate folklore surrounding them. After Lord Nelson lost his right arm during an unsuccessful attack on Santa Cruz de Tenerife, he experienced compelling phantom limb pains, including the sensation of fingers digging into his phantom palm. The emergence of these ghostly sensations led the sea lord to proclaim that his phantom was a 'direct proof of the existence of the soul.' If an arm can survive physical annihilation, why not the entire person?
Since the time of Mitchell's (1872) original description, there have been literally hundreds of fascinating clinical case reports of phantom limbs. However, there has been a tendency to regard the syndrome as a clinical curiosity, and very little experimental work has been done on it."
Denyse: "neurons that once received input from a vanished hand could rewire themselves to report input from the face."
Ramachandran: "We suggest that the phantom limb experience depends on integrating experiences from at least five different sources: (i) from the stump neurons, as taught by the old textbooks; (ii) from remapping, e.g. the spontaneous activity from the face is ascribed to the phantom: (iii) the monitoring of corollary discharge from motor commands to the the limb; (iv) a primordial, genetically determined, internal 'image' of one's body; and (v) vivid somatic memories of painful sensations or posture of the original limb being 'carried' over the the phantom. Ordinarily these five factors conspire to reinforce each other but in individual patients there may be discrepancies that modify the clinical picture."
Denyse's position hasn't moved much beyond that proclaimed by Lord Nelson after loosing a limb in 1797. So for much attending to the medical and experimental work done since then. And judge for yourselves who is trading in "simplicities."
Myth: Something that never was true, and always will be.
"The truth will set you free. But not until it is finished with you."
- David Foster Wallace