Scientists take first-of-kind human dopamine reading
research.vtc.vt.edu
research.vtc.vt.edu
> “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.”
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
1. http://www.ncbi.nlm.nih.gov/pubmed/10195184 2. https://en.wikipedia.org/wiki/Bayesian_approaches_to_brain_f...
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).