Monkeys Lead Scientist to Answers about Anxiety

Anxiety and other mental disorders have given researchers a lot to think about over the years. It is often difficult to discern if anxiety is passed down through genetics, or if it is a learned behavior form living with anxious parents. Patterns in the brains of monkeys with anxious actions have offered some perspective on the subject. Everyone’s brain operates in a unique way. This unique pattern is formed by both genetics and experiences. Certain characteristics in behavior, and activity in the brain have been found to be present in related monkeys.

Brain Activity

Scientists have focused on a specific pattern of brain activity when studying the monkeys. This pattern has shown to follow a certain path through family members. This is similar to the path that anxiety takes in a related group. Physical activity was also observed in the monkeys to determine which ones may be prone to anxiety. Like in human children, certain traits are present early on, long before a severe anxiety disorder is diagnosed.

The monkeys were exposed to a stressful situation and their behavior was recorded, along with cortisol (the stress hormone) levels. Normal stress responses were exaggerated in some of the monkeys. The brains of the monkeys were scanned and found to have a significant difference than those without anxious tendencies. The extended amygdala was observed in the ones that were more stressed out by the stimulus of an intruder in their cage. This part of the brain plays a big part in the recognition of threats and fear.

The Family Tree

Other noticeable traits in the brain were discovered to also be present in others of the same family tree. Two parts of the brain that seem to work together are the bed nucleus of the stria terminalis and the central nucleus. A heightened activity in one is also met by high activity in the other. These changes were observed by magnetic resonance imaging scans. The linked ability of these two parts of the brain was what showed in scans of related individuals. The observed anxious personality traits were also present with this brain activity.


There is still the question of whether brain differences cause anxiety, or whether anxiety causes the brain to change. This question is something that continues to interest scientists. The amygdala and areas surrounding it would have to be manipulated to see if the anxious behavior dissipates in response. The current studies offer an excellent starting point to find the cause of anxious behavior. It also gives a better idea of how the issues travel genetically. It may be a long time before treatment for anxiety is determined from these studies. The foundation, however, has been formed for future researchers to find an answer.

Anxiety plagues a large part of the population. Numbers have been steadily rising over the last 50 years, especially. Many people simply blame it on a more stressful environment. Scientists, however, are looking at the brain to see if they can find where these disorders originate. Treatment options could very well improve at some point in the future.


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