I've waited a patient four days for this message to appear. Since
it hasn't, I conclude it's lost and gone forever in cyberspace.
Here it is again.
The 19th century physiologist Johannes Muller proposed a "law
of the specific energies of nerves", the idea that sensations
depend on which nerves are activated, not on the nature of the
stimulus that provokes them. For example, a beam of light on the
retina and a smack in the eye both cause a visual sensation.
I've long illustrated this concept with the charming speculation
of a 19th century physiologist (Muller himself?). He proposed
that if the auditory and visual nerves could be crossed (so that
the auditory nerve reports to the visual cortex and the optic
nerve to the auditory cortex), then we would "see thunder and
hear lightning".
The problem is, I don't have a clue where I got this from. Does
anybody know?
The reason I'm currently hot on this topic is that a remarkable
paper was just published in Nature (which, unfortunately, hasn't
yet arrived in our library) which appears to settle the question.
Von Melchner et al (2000) found a way to get the visual pathway
in ferrets to connect with the auditory cortex. In behavioural
tests, the ferrets still responded to a light as a visual
stimulus. In other words, they still see lightning, but with
their auditory cortex. Amazing, isn't it?
Muller himself couldn't make up his mind whether the "specific
energy" was due to the nerves or where they terminate in the
brain. Most of us have placed our money on the termination in the
brain. It looks like we were wrong.
A journalistic account is available at:
http://www.nytimes.com/library/national/science/042500sci-animal-ferret.html
Von Melchner, L., et al (2000). Visual behaviour mediated by
retinal projections directed to the auditory pathway. Nature,
404, 871-876.
And don't forget about my query!
-Stephen
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Stephen Black, Ph.D. tel: (819) 822-9600 ext 2470
Department of Psychology fax: (819) 822-9661
Bishop's University e-mail: [EMAIL PROTECTED]
Lennoxville, QC
J1M 1Z7
Canada Department web page at http://www.ubishops.ca/ccc/div/soc/psy
Check out TIPS listserv for teachers of psychology at:
http://www.frostburg.edu/dept/psyc/southerly/tips/
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