The hormone testosterone increases activity in the brain's emotion center – the amygdala, according to a new study from Radboud University. It only happens when an individual approaches a threatening situation. Testosterone does not alter amygdala activity when the person avoids such a threatening situation. This study suggests that motivation influences the amygdala more than emotions.
The experiment showed that the increased activity in the amygdala happens only when confronted by a threat, such as an angry face. It does not happen in the absence of a threatening situation.
Karin Roelofs, Experimental Psychopathology Professor at Radboud University, said, “It seems that testosterone facilitates social approach by specifically activating the amygdalae only if social approach is desired.”
According to Roelofs, this is important for two important reasons. First, it explains that approaching a threatening situation is easier with higher testosterone levels. Second, this proves that the amygdala has a stronger link with motivation than it has with emotion.
Roelofs also added that a lot of studies overlook the importance of motivation. Radboud is the first to study the amygdala-testosterone link within specific motivational contexts.
The research involved a placebo-controlled double-blind experiment. Fifty-four healthy young women took either a placebo or a dose of 0.5 mg testosterone using a supplement such asSpartagen. Researchers administered the dose four hours prior to a brain scan.
This dosage is much lower than the standard dose administered during a sex-change operation. It is also lower than what sports people take for performance. However, it can still have a significant effect on brain activity.
While the participants were inside the MRI-scanner, they saw pictures of angry or happy faces. Each participant then gave either a sign of approach or of rejection towards the face.
It was already known that it is easier for people to approach a happy face than an angry one. The reaction time taken by the participants confirmed this.
Researchers also found greater amygdala activity in the testosterone administered group. But this increase in amygdala activity only happened upon approaching an angry-looking face.
Individuals with social anxiety often suffer from lower levels of testosterone. Roelofs said they will repeat the experiment with people suffering from social anxiety. There is hope to find a treatment for this condition with testosterone administration.