You think that your brain stays safe from hackers? Maybe it does for now, but not for long: An experiment showed that stimulation of a particular brain region intervened in free will of monkeys and changed their preferences.
Researchers from Harvard University, MIT and the University of Leuven in Belgium claim to have managed to interfere with the function of the “ventral tegmental area”, or VTA, a region that belongs to the so-called reward system of the brain and is involved in the regulation of our preferences.
The intervention made monkeys choose a different picture from the one they would normally prefer. The VTA produces dopamine, a substance that causes pleasurable feelings, when the brain receives a reward. Depending on whether the dose dopamine is small or big, the brain learns to prefer certain things and avoid some others. In other words, the reward system makes the brain prefer the stimuli that bring pleasure and avoid those that do not stimulate the dopamine system.
The latest study, which will be published on 16 June in the journal «Current Biology», “is the first to confirm a causal relationship between the ventral tegmental area and the selection behavior in primates,” say the researchers.
In the first phase of the experiment, the researchers showed to each monkey a couple of pictures – for example a star or a ball – and let it choose freely. After a few repetitions, the researchers knew the preference of each experimental animal.
In the next phase they introduced electrodes into the brains of monkeys and caused dopamine release by inducing weak electrical current to the VTA, while the monkeys were looking at an “unwanted” image. As a result, this stimulation made the animals reverse their preferences and select, for example, the star in place of the ball.
In the next phase of the experiment, the research team followed the same tactic to restore the preferences of animals back to their original condition. Could the same method be applied for changing human preferences? “Theoretically yes,” replied the professor Wim Vanduffel of the University of Louvain.
The scientist notes that the VTA is a small area, hidden deep in the brain, which can be artificially stimulated only with invasive procedures such as those used in the experiment. In recent years, brain implants which stimulate specific areas of the brain were proved to treat disorders such as depression and obsessive-compulsive disorder.
As pointed out by Dr. Vanduffel, connecting electrodes to the ventral tegmental area would require much higher levels of surgical precision.
But if it becomes possible in the future, the method could be used in treating disorders that are associated with the function of the reward system, such as addiction and learning difficulties.