Rich, (01)
Thanks for the references: (02)
> http://www.caltech.edu/news/do-fruit-flies-have-emotions-46769
>
> Here is a TEDx talk by the same professor (David Anderson):
>
> http://tedxcaltech.caltech.edu/content/david-anderson (03)
One point that Anderson makes confirms a claim that I have often
repeated: there is a huge amount of diversity or heterogeneity in
the way different parts of the brain work. (04)
Anderson noted that the same chemical -- dopamine in this case --
had very different effects in different parts of the brain. A pill
that increases or decreases dopamine levels in all parts of the
brain would be a very crude tool. (05)
RC
> Would it be possible to automate an evoked response that demonstrates
> each emotional state designated by the professor as a "component"?
> If so, would it then be possible to write an ontology discovery program
> that explores that space using a buncha fruit flies crossed with a
> buncha experimental situations? (06)
Note what he said: if you consider dopamine level as a feature or
component, it's going to have different effects on different circuits.
Any theory based on a weighted sum of inputs (as many neural networks
and related methods do) is going to be a very gross oversimplification.
It might give useful results for some purposes, but not for others. (07)
For anybody who wants to know more about the brains of insects and
other arthropods, I recommend the following book: (08)
Strausfeld, Nicholas James (2012) Arthropod Brains: Evolution,
Functional Elegance, and Historical Significance, Cambrdge, MA:
Harvard University Press. (09)
The price is $68.50 at Harvard U. P., Amazon, or Barnes & Noble.
But it's beautifully illustrated -- it's like a technical coffee
table book. (010)
I did a bit of googling and found a recent discovery by Strausfeld:
> http://www.livescience.com/23862-oldest-arthropod-brain-complex.html (011)
One of his colleagues had found a fossil of an arthropod that was
520 million years old. While examining it, Strausfeld could see
"the dark brown silhouette of preserved brain nestled in the arthropod's
skull":
> This complex, insectlike brain suggests that rather than insects
> arising from simple branchiopods, today's arthropods descend from a
> complex-brained ancestor. Branchiopods would later have shed some of
> this complexity, Strausfeld said, while other crustaceans and insects
> kept it. In fact, he said, the brain may have evolved to segment into
> three parts very early on; mammals, including humans, have a forebrain,
> midbrain and hindbrain, suggesting a common organization. (012)
If the overall structure has been preserved for over 500 million years,
it must be important. Any claim that the brain is a homogenous lump
with all neurons working in the same ways to do the same things must be
oversimplified. There may be some similar low-level mechanisms, but
they perform different functions in different parts of the structure. (013)
Bottom line: Don't expect a "unified theory" based on a simple
combination of features or components. (014)
John (015)
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