|
Response to Phantoms in the Brain
|
mmsmit-@aol.com
|
Dec 08, 2006 01:06 PST
|
Merritt M. Smith
Topica Discussion Response
“Phantoms in the Brain”
Experimental Neurobiology Fall 2006
This chapter from “Phantoms in the Brain,” was so skillfully written,
surely to intrigue and captivate almost any audience. The writing style
reminded me of The Double Helix, which disclosed Watson and Crick’s
marvelous discovery of the structure of DNA by way of a narrative. I
enjoyed the extensive amount of neurobiological history that was amassed
into this chapter, learning things such as the development of the
Penfield map. As an aside, this chapter also made me feel extremely
privileged to be taking an entire semester course that embarks on the
emerging Galilean approach the neurobiology as the vast amount of work
done in past clinical neurobiology has been merely a descriptive
approach.
Surfacing as early as the 16th century the mystery of the phantom limb
has long sense marveled scientist and been a legend of the common man.
What I appreciated most about the work on the phantom limb and
Ramachandran was the way he weaved his research on the matter into the
greater fabric of scientific discovery, hoping it would provide insight
to the great questions on Nature vs. Nurture- in this context, it was to
what extent is our body and our image determined by our genetic code and
what extent is modified by experience. Even pertaining more
specifically to the text at hand, the laying down of the somatotopic map
questions raised questions of whether such a map could be changed by
experience.
The journey to capturing the “phantom” seemed to originate with
Wilder Penfield’s contribution to the development of the sensory
homunculus, passing next to Tim Pons who worked initially with monkeys
having undergone dorsal rhizotomy and his subsequent findings of silent
areas of cortex that were associated with the paralyzed arm. From my
understanding of the article, it seemed that Pon’s findings were the
first showing that the “brain circuitry of an adult animal could be
altered.” From there, Ramachandran followed in suit, being in
accordance with this hypothesis after his experiments using MEG on four
arm amputees showed that the maps changed over long distances- the area
of the right hemisphere corresponding to a presently missing hand had
been invaded by sensory input from the face and upper arm. Near the end
of this chapter, Ramachandran posed two theories for the mechanism of
the phantom limb at the cellular level. I am under the persuasion, that
Ramachandran’s “hunch” is correct; reorganization results from both
sprouting and from a generous amount of redundant connections in the
brain that are under inhibitory control in what we deem the “normal”
human.
|
|
 |
|
