Fear is a strong emotional sensation that also causes physical responses: it makes you pale, shiver, pant, sweat. But it is fundamental, because it allows us to react quickly and effectively when we find ourselves in risky situations. It is therefore completely normal if its intensity is proportionate to the threat.
to activate fear from the physical point of view, is a precise neurophysiological process. “Fear is triggered when our sensory systems (visual, auditory, etc.) perceive a stimulus that has a dangerous character.
This perception immediately starts the activity of the limbic system, triggering the condition of ‘fight or flight’, that is, fight or flight”, as Antonio Cerasa, neuroscientist of the Institute for Biomedical Research and Innovation (Irib) of the CNR, explains.
” It is neurobiologically possible to study the neural genesis of fear using what is called ‘fear conditioning,’ a simple conditioning protocol between a neutral stimulus and a painful stimulus. Once the conditioning is initiated, new neural plasticity is formed within the hippocampus (memory area) that is activated every time we are faced with the stimulus that has been conditioned. However, the fear network also involves other structures such as the amygdala and the orbitofrontal cortex. And it is precisely the amygdala that activates the hypotholamus-pituitary-adrenal axis to initiate a series of chain reactions, such as increased heart rate, respiration, hyperactivity, hypervigilance, cortisol release. This series of events has a strong repercussion on the human body, where fear is localized expressly at the level of the heart and stomach.
In some cases, however, this natural feeling reaches excessive levels. “The mechanism of fear works perfectly when it comes to normal adaptations to the external environment, but when it reaches pathological levels you can get to develop post-traumatic stress disorder (Ptsd),” clarifies the researcher. “This happens because events or stimuli have left such a level of stress in memory as to induce strong organic and psychocognitive imbalances, which are repeated every time the person comes into contact (even imaginary) with the trigger stimulus, i.e. the element capable of reactivating memories related to the traumatic experience”.

 

 

 _{Oiginal article on:Almanacco della Scienza: almanacco.cnr.it}