Dopamine release in human brain tracked at microsecond timescale reveals decision-making

A research team led by investigators at the Virginia Tech Carilion Research Institute has demonstrated the first rapid measurements of dopamine release in a human brain and provided preliminary evidence that the neurotransmitter can be tracked in its movement between brain cells while a subject expresses decision-making behavior.

"In an experiment where we measured release while a subject made investment decisions in a stock market trading game, we showed that dopamine tracks changes in the value of the market," said Read Montague, director of the Human Neuroimaging Laboratory at the Virginia Tech Carilion Research Institute and professor of physics in the College of Science at Virginia Tech.

"A startling discovery was that the dopamine signal appeared to be a very good indicator of the market value and in many instances a good predictor of future market changes," said Kenneth Kishida, a postdoctoral associate with the Human Neuroimaging Laboratory and the lead author on the report. Interestingly, the choice expressed by the subject did not always correspond with the prescient , he said.

The research was published on Aug. 4, 2011, in the Public Library of Science journal, PLoS ONE, in the article "Sub-Second Dopamine Detection in Human ," by Kishida; Stefan G. Sandberg, senior fellow with the Departments of Psychiatry and Behavioral Sciences and Pharmacology, University of Washington, Seattle; Terry Lohrenz, assistant professor in the Department of Neuroscience, Baylor College of Medicine; Dr. Youssef G. Comair, professor and chief, Division of Neurosurgery, American University of Beirut, Lebanon; Ignacio Saez, assistant professor at Virginia Tech Carilion Research Institute; Paul E. M. Phillips, associate professor, Departments of Psychiatry and Behavioral Sciences and Pharmacology, University of Washington, Seattle; and Montague, senior author.

The researchers adapted their sensors to existing technology used for functional mapping of the brain during surgical implantation of deep-brain stimulation devices. "Deep-brain stimulation is typically used in the treatment of Parkinson's disease," said Montague. "Uses for treating other neurological disorders are also being investigated, though, and may open new avenues for the technology we developed."

The researchers applied criteria that employed experimental methodology that is "safe to the patient, compatible with existing neurosurgical apparatus and the operating-room environment, and capable of sub-second detection of physiological dopamine," they state in the article. They modified existing sensor technology to improve signal conductivity, creating a microsensor that shares the electrochemical properties of existing electrodes yet can detect sub-second . "Even more important, the new microsensors are biocompatible and can be sterilized without affecting performance, " Kishida added.

The new instrument was demonstrated in a single human subject, a consenting patient with late-stage Parkinson's disease who was undergoing elective surgery for deep-brain stimulation electrode implantation. The new microsensor was placed in the patient's brain and dopamine release was monitored as the patient engaged in a decision-making game. The current value and recent history of a stock market was graphically represented on a laptop monitor. The subject chose the proportion of a portfolio initially valued at $100 to be invested in the stock market. Decisions were submitted by pushing buttons on handheld response devices. Following the submission of each decision, the market was updated. The final portfolio determined the actual payout at the end of the experiment.

The researchers report that they were surprised to observe that "the slope of the dopamine signal over a period five seconds prior to a market price update correlated with subsequent market returns…, demonstrating that it is a significant predictor of future market activity."

To test this hypothesis, the researchers constructed a trader model that made decisions based on the fluctuations in the dopamine signal leading up to the market price changes. This decision model invested 100 percent, or all in, when the dopamine slope was positive and 0 percent, or all out, when the slope was negative. The researchers report that, "Over the five markets played, this trader model earned 202 points (a gain of 175 percent), more than two times the amount earned by the subject's expressed behavior. These data demonstrate that the information encoded in the dopamine signal of this patient is potentially useful for economic decision making."

"This exciting preliminary result requires replication, but it immediately sets the imagination in motion," said Kishida. "I often wonder whether there is a feeling associated with these dopamine fluctuations and whether there is any connection with that 'gut feeling' people sometimes ignore."

Writing in the article, the researchers conclude, "This methodological demonstration opens the door to future investigations utilizing sub-second chemical measurements in the , which should yield important insights into the role of dopamine signaling in human decision-making."

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210
not rated yet Oct 28, 2011
The more we labor to learn about how the BRAIN works, the efforts return-on-investment, at present, is almost flat with regard to more information about the mind. For example, the mind - where is it?
Poor decision making can be attributed to many diseases, immaturity, incomplete development, nutrition, drugs and toxic effects of pollutants, other environmentals, and parasites to name large factors readily evident. But the mind, is it coupled to our existence electromagnetically? Then why have we NO data for this. That is, a domain of frequencies that correspond to brain wave patterns or deep concentration, etc. IS there a missing quantum component to the mind/brain research effort? Do we exist mentally, in corresponding quantum effects/properties?
A question.
word-to-ya-muthas
Callippo
2 / 5 (3) Oct 28, 2011
is it coupled to our existence electromagnetically? Then why have we NO data for this

Because the neural waves aren't pure electric waves, neither mechanical waves. They're something inbetween.

http://aetherwave...ess.html

By recent studies neural solitons are sound waves supported by electrochemical activity of neural cell membranes. The membrane potential contracts the membrane, which is in elastic liquid crystal state. After sound wave arrival the membrane potencial is discharged by diffusion of ions via ion channels and the membrane surface follows a self reinforcing wave, i.e. the soliton. The whole process repeats itself in ~100 Hz cycle.
210
1 / 5 (1) Oct 28, 2011


Read the link: http://aetherwave...ess.html

There may indeed be a quantum component to the concept of mind, thanks.

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xznofile
not rated yet Oct 29, 2011
It probably means that dopamine production is responding to awareness which hasn't been filtered through caution. A gut feeling could describe it, but after-the-fact decisions to go with gut feelings simply ignore caution. There's a learning process that defines those things, & more experience strengthens successful synapses. I think dopamine is the feeling of success, & we all crave it.
Skultch
5 / 5 (2) Oct 29, 2011
While quantum consciousness sounds cool and all, are their any abilities of the human mind that cannot be adequately explained by classical physics?
210
not rated yet Oct 30, 2011
While quantum consciousness sounds cool and all, are their any abilities of the human mind that cannot be adequately explained by classical physics?
Yes...where is the mind? How is it connected to our physical manifestation of consciousness? How do we know that, 'we know'? When does 'mind' begin? Are certain or all attributes of the mind inheritable? etc, etc, etc...
word-
roboferret
not rated yet Oct 31, 2011
Yes...where is the mind? How is it connected to our physical manifestation of consciousness? How do we know that, 'we know'? When does 'mind' begin? Are certain or all attributes of the mind inheritable? etc, etc, etc...
word-

What do you mean by the "mind"
Conciousness appears to be an emergent property of the various functions of the brain. If the brain is damaged, intelligence can be impaired. A knock-out punch traumatises the brain, and the unfortunate recipient looses consciousness. There is nothing to suggest that the mind is anything other than the software, if you will, of the brain, or that the brain is anything than a very complex biochemical computer. Our brain structure, like other physical features, will be inherited initially, but it's development will largely depend on personal experiences.
Skultch
not rated yet Oct 31, 2011
While quantum consciousness sounds cool and all, are their any abilities of the human mind that cannot be adequately explained by classical physics?
Yes...where is the mind? How is it connected to our physical manifestation of consciousness? How do we know that, 'we know'? When does 'mind' begin? Are certain or all attributes of the mind inheritable? etc, etc, etc...
word-


I asked about the abilities themselves, not the source of them.

I'll ask it a different way, if that helps. What is your brain capable of that necessitates a quantum explanation? If you must talk about the source, then in order to answer fully, you will have to show how the classical explanation is insufficient. If you can't describe the classical explanation in your own words, what makes you think that you are qualified to propose an alternative? (I'm not saying you can't; I'm just preempting a response, JIK)