Many of us, as soon as we stand in a dark place, get goosebumps, and fear begins to seep into them, without knowing the real reasons for it.
American scientists believe that they may have discovered the brain mechanisms behind the fear of the dark, especially in children.
A new study sheds light on how brain activity changes when we are exposed to light and darkness, mechanisms that operate in two brain regions in particular, according to this research.
The study, carried out by a group of researchers from American research centers and universities, was published on the Pulse One website, which specializes in scientific publications and field research abstracts.
The study authors found that there is a relationship between the amygdala and the way we process emotions and regulate our fear response.
Neuroscientists, mental health experts, and university psychologists participated in the study. The study analyzed how brain activity changes in this area when we are exposed to light and darkness.
The researchers who participated in this study wrote in this regard, moderate exposure to light suppresses amygdala activity more than dim light, while exposure to darkness inflames this area.
Moreover, the presence of light appears to strengthen the link between the amygdala and the ventromedial prefrontal cortex, another part of the brain associated with controlling our sense of fear.
In this new research, fMRI brain scans of 23 people were analyzed as they were exposed to 30-second periods of low to medium light, as well as darkness, and the scans lasted about 30 minutes in total.
It turns out that moderate lighting causes a 'significant decrease' in amygdala activity, with low light being reduced.
It also turns out that there is greater "functional connectivity" between the amygdala and the ventromedial prefrontal cortex during the times when the lights were on.
In other words, the light may keep the brain's fear management centers running, based on this small sample of volunteers.
The team said, we'll need more data to know exactly what's going on, but the disconnect between these brain regions has previously been associated with anxiety. These variables may contribute to the mood-improving effects of light, by reducing the negative impact associated with fear and improving the processing of negative emotions.
The relationship between light, dark, and activity in the brain is well established. Changes in light help us tell when to sleep, have an impact on our levels of alertness, and can affect our mood as well. One way to deal with this specific phobia may be the ability to control exposure to light. Light is already widely used in some treatments for conditions such as depression, although scientists have only recently understood how or why the lighting works.
The results of this study could be the key to so-called photosensitive retinal ganglion cells (ipRGCs), which take light from the eye and transmit it to different parts of the brain.
The next step in the study will be to learn more about how they interact with the amygdala. Further work will be required to begin to understand the unique contribution of different subsets of ipRGCs, and other photoreceptors, to both visible and non-visible aspects of light responses.