Some 99 volunteers agreed to be wired up and placed inside a functional magnetic resonance imaging scanner. Most of those acted as controls, including some who were wired up but did not receive the current, but 19 got the full treatment. While in the scanner they were asked to rate the attractiveness of a series of human images, both before and after the current was applied.
The scanner monitored activity in two areas, one just behind the forehead, which is close enough to the surface for the technology to manipulate. The researchers theorized that if they used the weak current to deactivate that area, that would cause a rise in activity in the midbrain -- the area they could not reach directly.
And that's exactly what they found. They were able to increase activity in the midbrain, the reward center, and that caused an increase in the perception of attractiveness in the images.
A tiny electrical stimulation caused a behavioral response, and the stronger the stimulation, the better looking the images seemed. None of the controls experienced anything like that.
Crib said the team has passed the proof of concept phase, but much more remains to be done.
This technique could not measure an increase in dopamine -- sometimes called the love drug, which can also result in many psychiatric disorders if the supply is insufficient -- in the reward center, so the entire experiment must be repeated with a different scanner, probably positron emission tomography (PET.)
If it passes that milestone, it will probably move quickly into clinical trials because it may be useful in the treatment of such devastating diseases as Parkinson's and depression.