Funding for this site is provided by readers like you.
Emotions and the brain

Fear, Anxiety and Anguish

Help Link Module :  animation showing the location of the amygdala
Research Module: Montreal centre a leader in brain imaging

“Centres” of Cognitive Functions in the Brain: A Misleading Concept

Emotions such as fear and perceptions such as vision are not produced at any single location in the brain that might be called the “fear centre” or the “vision centre”. Instead, these functions depend on several interconnected areas of the brain, which are called systems. Each function has its own system which is a unique set of several regions of the brain that are connected to one another.

In the case of fear, for example, destroying an animal’s amygdala has disastrous effects on its natural alarm system. But that does not make the amygdala the “fear centre”, because the amygdala also has connections coming in from and going out to several other parts of the brain, all of which also are needed to manifest fear.


The amygdala is an almond-shaped structure in the brain; its name comes from the Greek word for “almond”. As with most other brain structures, you actually have two amygdalae (shown in red in the drawing here). Each amygdala is located close to the hippocampus, in the frontal portion of the temporal lobe.

Your amygdalae are essential to your ability to feel certain emotions and to perceive them in other people. This includes fear and the many changes that it causes in the body. If you are being followed at night by a suspect-looking individual and your heart is pounding, chances are that your amygdalae are very active!



Source: University of Washington Digital Anatomist Program

In certain studies, researchers have directly stimulated the amygdalae of patients who were undergoing brain surgery, and asked them to report their impressions. The subjective experience that these patients reported most often was one of imminent danger and fear. In studies of the very small number of patients who have had had only their amygdala destroyed (as the result of a stroke, for example), they recognized the facial expressions of every emotion except fear.

In fact, the amygdala seems to modulate all of our reactions to events that are very important for our survival. Events that warn us of imminent danger are therefore very important stimuli for the amygdala, but so are events that signal the presence of food, sexual partners, rivals, children in distress, and so on.

That is why the amygdala has so many connections with several other structures in the brain.


Linked Module: Animation showing the location of the amygdala Linked Module: Est-ce qu'une emotion peut être déclenchée sans l'intervention de la pensée consciente?
Original modules
Experiment Module: Identifying the Brain Structures Involved in Conditioned Fear Identifying the Brain Structures Involved in Conditioned Fear

Emotions are something that happens to us much more than something we decide to make happen. Much of the explanation for this lack of direct control over our emotions lies in the way that the human brain is interconnected. Our brains have evolved in such a way that they have far more connections running from our emotional systems to our cortex (the locus of conscious control) than the other way around.

In other words, the noise of all the heavy traffic on the major highway running from the limbic system to the cortex masks the quieter sounds on the little road running in the other direction.


The amygdala lets us react almost instantaneously to the presence of a danger. So rapidly that often we startle first, and realize only afterward what it was that frightened us. How is this possible?

It all has to start, of course, with a sensory stimulus, such as a strange shape or a menacing sound. Like all information captured by the senses, this message must be routed first to the thalamus. The thalamus then sends this message on to the appropriate sensory cortex (visual cortex, auditory cortex, etc.), which evaluates it and assigns it a meaning. If this meaning is threatening, then the amygdala is informed and produces the appropriate emotional responses.

But what has been discovered much more recently is that a part of the message received by the thalamus is transferred directly to the amygdala, without even passing through the cortex! It is this second route, much shorter and therefore much faster, that explains the rapid reaction of our natural alarm system.

Since everything has a price, this route that short-circuits the cortex provides only a crude discrimination of potentially threatening objects. It is the cortex that provides the confirmation, a few fractions of a second later, as to whether a given object actually represents a danger. Those fractions of a second could be fatal if we had not already begun to react to the danger. And if the cortex turns out to advise us that there is nothing to worry about after all, we have merely had a good scare, and that is it.

Children have less control over their emotions, because the axons that send information from the cortex to the limbic system are not yet fully developed. In addition, the neurons of the prefrontal cortex that provide much of our rational control over our emotions do not mature until early adulthood. In contrast, the amygdala is mature at birth and thus exerts a heavy influence on children.

  Presentations | Credits | Contact | Copyleft