Afraid of The Dark? Blame Your Brain, Not Monsters Under The Bed
Fear is a common response to darkness, especially in children, and now scientists think they might have figured out the brain mechanisms behind it, mechanisms that work in a couple of areas of the brain in particular.
The amygdala section of the brain is responsible for processing emotion and regulating our fear response, and a new study highlights how brain activity in this region changes as we're exposed to light and darkness.
"Light, compared with dark, suppressed activity in the amygdala," write the researchers in their published paper. "Moderate light exposure resulted in greater suppression of amygdala activity than dim light."
What's more, the presence of light seems to strengthen the link between the amygdala and the ventromedial prefrontal cortex, another part of the brain that's associated with controlling our sense of fear.
In this new piece of research, fMRI brain scans from 23 people were analyzed as they were exposed to 30-second periods of dim (10 lux) and moderate (100 lux) lighting, as well as darkness (<1 lux). The scans lasted around 30 minutes in total.
The moderate lighting was shown to cause a "significant reduction" in amygdala activity, with dim lighting causing a smaller reduction. There was also greater "functional connectivity" between the amygdala and the ventromedial prefrontal cortex during the times when the lights were on. ...
In other words, light might keep our brain's fear management centers in operation, based on this small sample of volunteers. We'll need more data to figure out what exactly is happening, but disconnects between these brain areas have previously been linked to anxiety. ...