Understand your emotions: fear.

The neuroscience of emotions reveals how our brains create fear without any real danger.

Emotions, such as love, hate, happiness, and sadness, are feelings we experience through the course of life. We should not worry about having those feelings, as many things trigger emotional responses (e.g. a funny joke, a spider, or a kiss). However, if you are like me, seeking to understand emotional responses, then wishful thinking is not an alternative. We need scientific explanations that lead to positive changes and results.

Before you accuse me of being “a cold-heart person” or “too rational” let me suggest a different way of thinking about emotions: the scientific and romanticised approaches to emotions are not mutually exclusive. Thus, if you enjoy the connection between words and images with feelings, then watching a movie or reading poetry are rich sources of inspiration. 

However, if you seek to improve your health and learn about your behaviours, then science is the answer. Otherwise, cardiologists would prescribe reading Dante Alighieri’s The Divine Comedy as a medication to patients who suffered a stroke. Well, I hope to have convinced you that science can offer reliable information that no poetry can.

The amygdala

There is no single brain structure responsible for processing emotions. The experience and expression of emotions involve several neural pathways connecting different areas of the brain; from photoreceptors in the retina to neurons in the frontal lobe, feelings are complicated to measure. 

However, there is one structure that has received a lot of attention from neuroscientists—the amygdala. As part of a larger group of brain structures, called the limbic system, the amygdala sits in the mid-bottom part of the brain. We have two, almond-shape, amygdalae one in each side of the brain (in red).

Researches have shown that lesions in the amygdala result in flat emotional expressions [1]. This means that compared to participants with the intact amygdala, those with damaged amygdala display fewer emotional reactions to a stimulus. Moreover, bilateral lesions (i.e. damage to both amygdalae) in rats profoundly reduce aggression and fear, even in the presence of a predator, such as a cat [2]

In the USA, a 30-year-old woman, with average intelligence and perfect ability to identify people from pictures, suffered from a disease that destroyed both her amygdalae. Interestingly, when asked to categorise the types of facial expressions (e.g. happy, sad, and so on), the women struggled to identify fearful expressions as afraid [3]. These findings indicate that the amygdala plays a role in emotional response, but more importantly, it involves the processing of fear.

Now, you could ask me: if damage to the amygdala reduces emotional expression, then what happens if researchers stimulate an intact amygdala? Animal studies have shown that stimulation of the amygdala elicits violent aggression and fear [1]. Similarly, human studies have reported that the stimulation of the amygdala generates fear, which increases symptoms of anxiety [4]. Therefore, research-based information of amygdala may explain how fear affects emotional reactions to casual real-life social events (social anxiety) and objects (phobia). Interestingly, anxiety is a comorbid symptom of depression, another disabling disorder.

 Fear helps you to learn (quickly)

As a child, some of us have received a shock by pushing a paper clip into a power plug. Certainly, we never did it again. The brain has the capacity of quickly forming fearful memories, which last for a long time. Otherwise, we might repeat the same mistake as an adult. Therefore, the combination of fear and memory supports learning. 

However, the amygdala also activates upon the perception of a threat. In a neuro-imaging study, researchers presented to participants frightening images of violence and mutilated bodies. The results revealed activation in the amygdala as well as an increase in physiological activities, such as heart rate and skin conductance (i.e. sweat). 

Psychological complexity

Fear is essential and prevents us from getting dangerous situations; however, not every situation is life-threatening. For instance, public speaking or asking your boss for a raise will not get you killed but might trigger fear in doing so. There are many reasons why you could feel afraid; rejection, failure, embarrassment, judgement, and so on. 

The brain does not distinguish whether the thinking of a potential mistake during a presentation is the same threat as seeing a car speeding in your direction. This means that just by thinking we can trigger emotional fear and physiological activities and, thus, influencing our decision. For example, you might be so afraid of embarrassment that you never get to do your first presentation to a broad audience (i.e. fear of public speaking). As a consequence, you might never get a promotion because of fear. Really?!

Next time, I will explain how emotions affect our decision-making process. It is never a good idea to make a decision when you are either angry or happy.

Let me know in the comments what thought or social situation triggers fear in you. How do you react? How would you like to respond? 

Remember: fear is real, danger not always. 

References:

[1] Bear, M. F., Connors, B. W., & Paradiso, M. A. (Eds.). (2007). Neuroscience (Vol. 2). Lippincott Williams & Wilkins.

[2] Flynn, J. P. (1967). The neural basis of aggression in cats. Neurophysiology and emotion.

[3] Breiter, H. C., Etcoff, N. L.,… & Rosen, B. R. (1996). Response and habituation of the human amygdala during visual processing of facial expression. Neuron, 17(5), 875-887.

[4] LeDoux, J. (2007). The amygdala. Current biology, 17(20), R868-R874.

[5] Hamann, S. B., Ely, T. D., Grafton, S. T., & Kilts, C. D. (1999). Amygdala activity related to enhanced memory for pleasant and aversive stimuli. Nature neuroscience, 2(3), 289.

Image by Jeremy Bishop

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