The Brain

The Brain

What happens to specific regions in the brain when you feel anger and fear? Before you became angry and fearful, you had to determine if there was something to be angry and fearful, you had to determine if there was something to be angry and fearful about. This is the evaluation, appraisal, step, mediated in part by higher regions of the brain and in part by the amygdala.

The amygdala is an almond-shaped part of a larger complex called the limbic system. It looks like a small scorpion stuck in the middle of your head. The claws of this scorpion are the amygdalae. You have two amygdalae embedded into your brain, one on the left and one on the right.

The amygdala is the region most responsible for tagging a given sensory input with an emotional message. The amygdala helps generate emotional experiences and also helps in remembering them. It does this mostly unconsciously, out of sight of our awareness. Those talented claws take input from all five senses and return to the brain the beginnings of what may be a memorable emotional reaction.

When you experience anger and fear, signals are sent deep into your brain's interior, arriving at the thalamus, that egg-shaped structure in the middle of your brain that sits on the back of the scorpion. The signal is sent down two neural paths simultaneously once the thalamus is finished with it. One path goes directly to the amygdala, via a highway LeDoux calls the fast path. That may be the emotion part and mostly lies out of your awareness. But not for long.

The second signal is shuttled to the cortical regions necessary for you to consciously process your anger and fear. After visiting the cortex, those signals are routed back at the amygdala. That may be the feeling part – but because it has to visit more brain regions, it's a much slower signal. Not surprisingly, LeDoux calls it the slow pathway.

Emotions and their accompanying feelings have deep survival benefits. Illustration by Elena.

Because the fast pathway is obviously faster than the slow pathway, you may begin responding emotionally to something you see before you're consciously aware of even looking at it. But the emotion will be there when you do, thanks in large part to your amygdala.

This doubly stimulated almond is not alone in processing emotional responses. As the amygdala understands the meaning what you're seeing, it starts alerting some of its neurological neighbors. One neighbor that gets a lot of attention is the hypothalamus.

The hypothalamus lies beneath the thalamus. It's small and thin – only about one-tenth of an inch thick. But don't let its small size fool you. The hypothalamus is also involved in handling the big emotions processed by the rest of the brain, from feelings of stress to feelings of hunger. You can artificially stimulate it and derive feelings of pleasure. You may even feel like projecting your genes into the next generation.

The hypothalamus is not just for romantic and sexual pleasure, though. If you get into a fighting mood as you view something that makes you angry or afraid, you can blame that on the hypothalamus, too. It also controls body temperature, so if your blood begins to boil, you'll know why.

Many regions of the brain are involved as you generate emotional responses. Some of these regions, such as the hypothalamus, alert the rest of the body that some kind of important deliberations are occurring and it had better pay attention.

Many of those bodily processes create chemicals and electric signals that go back to the brain, forming feedback loops. These loops inform the brain about the body's reactions, which in turn modifies the brain's experience of emotions and feelings – and even the behaviors that flow from them. That's why the brain and body are both the cause and effect of emotion, settling the controversy, or at least providing nuance to it.

Many regions of the brain are involved when experiencing anger and fear. Illustration by Elena.