Motivation may possibly move the emotional brain: Activity of amygdala higher in women administered testosterone, but only when they approached an angry face.

The Amygdala – often referred to as the ‘emotional brain’, due to the presence of emotion centers, might be influenced by motivation rather than emotions alone.

Researchers at the Radboud University found that the male hormone testosterone increased activity in the amygdala when a person encountered a socially threatening situation, and similarly decreased when the situation passed.

Motivation Concept

It was previously known that the amygdala of a person who had been given testosterone responded strongly to images of anger. In a double-blind, placebo-controlled study, 54 young and healthy women were administered a dosage of 0.5 mg testosterone/placebo four hours prior to having a brain scan. This dosage is extremely lower than that given during a sex-change treatment or as a supplement for sportsmen; however it is sufficient for measuring changes in brain activity.

How Amygdala Responds, Angry Or Happy?

While in the fMRI-scanner, the women were shown pictures of angry or happy faces. They had to respond by either rejecting (moving away) or accepting (moving towards) the picture and their responses were recorded in the form of reaction times. People normally take more time to move towards an angry face, since it requires more control and an effort to control fear – moving towards a happy face takes lesser time and effort. This theory was confirmed by the results of the research.

Meanwhile, the activity of the amygdala was higher in women who had been administered testosterone – but this was only when they approached an angry face.

“Previous research has shown that higher testosterone levels lead to an intensified amygdala reaction in the presence of angry faces,” stated Karin Roelofs, Professor of Experimental Psychopathology at the Donders Institute for Brain, Cognition and Behavior, Radboud University. “Those earlier investigations looked at what happens in non-active situations, and not during action. The focus was on what you should do if you see an angry face. Many studies forget to look at motivation. We are the first to demonstrate that the impact of testosterone on amygdala response depends on the motivational context.”

Conclusion

The study indicates that testosterone assists an individual in approaching a socially difficult situation – only if the approach is desired. This explains two things – testosterone makes it easier to approach a threatening situation, and the amygdala is not essentially linked to coping with emotions alone; it also plays a part in the motivation process.

“We are now going to repeat this study in people with social anxieties,” added Roelofs. “We have already discovered that these people have lower testosterone levels. We are going to consider how we can apply these results with testosterone to improve the treatment for anxiety disorders.”