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Fear may be a common response to darkness, especially in children, and now scientists think they could have found out the brain mechanisms behind it, mechanisms that work in few areas of the brain especially .
The amygdala section of the brain is liable for processing emotion and regulating our fear response, and a latest new study highlights how brain activity in-this region changes as we’re exposed to light & darkness.
“Light, compared with dark, suppressed activity within 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 appears to strengthen the link between the amygdala and therefore the ventromedial prefrontal cortex, another a part of the brain that’s related to controlling our sense of fear.
In this new piece of research, FMRI brain scans from 23 people were analyzed as they were exposed to 30sec periods of dim (10 lux) and moderate (100 lux) lighting, also as darkness(<1 lux). The scans lasted around half-hour 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 therefore the ventromedial prefrontal cortex during the days when the lights were on.
In other words, light might keep our brain’s fear management centers operational , supported this small sample of volunteers. We’ll need more data to work out what exactly is occurring , but disconnects between these brain areas have previously been linked to anxiety.
“These effects may contribute to light’s mood-elevating effects, via reduction in negative, fear-related affect & enhanced processing of negative emotion,” write the researchers.
The connection between light, darkness, and activity within the brain is well established: changes in light help us know when to sleep, have an impression on our levels of alertness, and may affect our mood also .
It’s possible that having the ability to control exposure to light – something that we’ve only been capable of very recently in our evolutionary history – might be a method of tackling this particular phobia. Light therapy treatments are already widely used for conditions like depression, though scientists don’t fully understand how or why they work.
The key might lie what are called intrinsically photosensitive retinal ganglion cells (ipRGCs), which take light in from the eyes and transmit it to different parts of the brain. subsequent step is learning more about how they interact with the amygdala.
“Further work are going to be needed to start to know the unique contribution of various subsets of ipRGCs, and other photoreceptors, to both the visual and non-visual aspects of light responses,” write the researchers.
The research has been published in PLOS One.
