Friday, May 30, 2014

Researchers Control Monkey’s Choice by Activating a Brain Region

According to researchers from Massachusetts General Hospital (MGH), activating a particular region of the brain affects the decision-making progress. The team was able to change monkeys' choices between two images by artificially stimulating the ventral tegmental area (VTA), which consists of a group of neurons located at the base of the midbrain.

"Previous studies had correlated increased activity in the primate VTA with positive events experienced by the animal but could not prove that VTA activity actually caused behavioral changes," stated study author, Wim Vanduffel, PhD, of the Martinos Center for Biomedical Imaging at MGH and head of the Laboratory for Neuro- and Psychophysiology at the University of Leuven. "Studies in rodents have shown that artificially manipulating VTA activity strongly influences behavior, and our work has bridged the gap between rodent and primate."

In this study, the team placed microelectrodes in the VTAs of macaque monkeys using high-resolution magnetic resonance imaging as a guide. In the beginning of the experiment, the monkeys were showed two images. The researchers recorded which image the monkeys preferred by observing their eye movements. The monkeys had been trained to look initially at a white square and then at either picture. The picture that the monkeys looked at most frequently was considered the favored one.

After knowing which image the monkeys preferred, the researchers showed the monkeys the picture pairs once again. This time when the monkeys looked at the less favored picture, the team administered mild stimulation to the VTA. The researchers noted that the stimulation caused the monkeys to change their preference. The stimulation was then applied when the monkeys glanced at their preferred image. The monkeys' preference changed back to normal.

Full story here.

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