SPAIN – An international team of scientists has discovered that, in dangerous situations that could pose a threat to our life, the brain uses a “shortcut” to send a “flash” alarm to the amygdala, the area responsible for processing memory, emotions, fear, defensive, aggressive behaviours and decision-making.

The research, published in Nature Neuroscience, help better understand disorders such as anxiety or phobias, and other currently difficult to treat diseases.

Bryan Strange, director of the Laboratory of Clinical Neuroscience Center of Biomedical Technology at the Polytechnic University Madrid (CTB-UPM) and lead author of the study said that when we see pictures of something that can be a threat, the amygdala is activated, an activity that can be measured with resonances and other functional neuroimaging techniques.

However, since the amygdala is a very deep structure of the brain, these techniques lack sufficient resolution to see how the process works. They needed other techniques such as the use of electrodes implanted in this brain region.

In this study, the researchers had the collaboration of eleven patients treated for epilepsy, where for a week electrode implants recorded all their brain activity. Two sets of experiments were conducted.

In the first, they were shown pictures of faces with neutral expression, fear and happiness.

Strange said that when the patients were shown the pictures of faces with fear, they observed that the activity of the amygdala lit up super fast, about 70 milliseconds, ie, the amygdala detected a threat in record time.

At the same time, the researchers recorded the activity in the visual cortex of these patients and found that in this area of the brain, after seeing the faces of fear, the response signal took 170 milliseconds to arrive, ie hundred milliseconds later than the amygdala, a time that is an eternity in the brain, said Strange.

In the second experiment, the patients were shown unpleasant scenes but not involving danger.

In this case, the activity in the amygdala took about 200 milliseconds, which means that the brain only uses the shortcut “to stimuli that represent a threat,” he concludes.

This shortcut is a neuronal circuit formed by type of neuronal cells, magnocellular, the fastest in bringing information to the brain, even if they are low frequency, poor quality or blurry said Strange.

The research concludes that this neural circuit is responsible for transmitting the most urgent information for survival, and that makes it so fast that it is an “automatic reaction that can not be consciously controlled.”

Knowing this will help you understand and treat diseases such as anxiety or phobias, because “it is important to know that there are mechanisms that are not controllable under our conscious and transmitted to the brain at such speed that are somewhat automatic.”