
Scientists take first-of-kind human dopamine reading - espeed
http://research.vtc.vt.edu/news/2015/dec/01/virginia-tech-carilion-research-institute-scientis/
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sawwit
Very interesting:

> _“Dopamine encodes what are called reward-prediction errors – the ongoing
> difference between reward expectations and the actual rewards experienced,”
> Montague said. “From just dopamine signals, we can see when a person expects
> a reward and whether the person receives the reward. But in our most recent
> study, we found this earlier model of reward-prediction error to be
> incomplete. Rather, dopamine pulses appear to combine information about what
> might have happened with information about what actually happened. This is
> an entirely new way of viewing the role of dopamine signaling in the human
> brain.” The idea that “what could have been” is part of how people evaluate
> actual outcomes is not new. But no one expected that dopamine would be doing
> the job of combining this information in the human brain. “We married two
> known computational models into something new,” Montague said. “In doing so,
> we found dopamine tracking and combining two streams of information into one
> chemical pulse.”_

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austinjp
Dopamine as the mediator molecule foe comparison of actual vs expected
experiences, very interesting indeed.

Seems to add a tiny sliver more evidence to my strong suspicion that the brain
contains "emulators", the output from which arrives milliseconds before
perception arrives from The Real World, allowing for pseudo-Bayesian updating
of the emulator(s), and of the whole-brain representation of the world, it's
effect on us, and our effect on it.

I come to this from a neuromusculoskeletal perspective, which is where I first
started reading about emulators. But I suspect they're a brain-wide
phenomenon, accounting for all sorts of oddness, including apparent "lag" in
consciousness.

More in my previous comments
[https://news.ycombinator.com/item?id=9931041](https://news.ycombinator.com/item?id=9931041)

~~~
Phemist
This view is quite common in computational neuroscience. Rather than calling
it Real World emulators, they call it predictive coding[1][2]. Models that are
able to predict statistical properties of "percepts", are able to store these
percepts in a much smaller coding scheme (information-wise). These models
generate predictions continuously (or emulate the Real World), and only update
themselves if supplied with sufficiently contrasting information.

1\.
[http://www.ncbi.nlm.nih.gov/pubmed/10195184](http://www.ncbi.nlm.nih.gov/pubmed/10195184)
2\.
[https://en.wikipedia.org/wiki/Bayesian_approaches_to_brain_f...](https://en.wikipedia.org/wiki/Bayesian_approaches_to_brain_function)

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nairboon
Direct link:
[http://faculty.washington.edu/pemp/pdfs/pemp2015-06.pdf](http://faculty.washington.edu/pemp/pdfs/pemp2015-06.pdf)

[http://www.pnas.org/content/early/2015/11/18/1513619112.abst...](http://www.pnas.org/content/early/2015/11/18/1513619112.abstract)

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0xcde4c3db
To expand a bit on the implications for depression treatment (NB: not an
expert, just someone who's read some things):

There are different patterns of how depression symptoms respond to nominally
rewarding experiences. Some people with depressive symptoms have a clear but
blunted response to rewards: mood elevates, but in a more subdued and fleeting
way than would otherwise be expected. This is associated with so-called
"atypical" depression, which is named not for its prevalence (it's common),
but for the idea that it doesn't fit the profile of "standard" depression.
Other people in depressive episodes seem to simply not process rewards at all,
often even experiencing guilt over their "failure" to be happy about
something. This is associated with "melancholic" depression. At least
superficially, it seems to match what might be expected if only the "what
could have been" side of the equation is functioning (i.e. everything feels
like a failure/disappointment).

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known
Oxytocin = Love; Dopamine = Lust;

