Monash Universiy’s Elise McGlashan studies the science behind a fear of the dark, the phobia of which is known as nychtophobia or achluophobia.

Much of the lab’s work has focused on modern artificial light and its effect on the mind and body, but Dr McGlashan has now co-led a fascinating new study into what an absence of light – the dark – can do to a central and very curious part of the brain, the amygdala.

Among other things, the amygdala is the brain’s fear centre.

The team studies the effects of a set of cells in the eye that respond to light, but don’t contribute to our ability to see. These cells contain the photopigment melanopsin, which is most sensitive to “blue light”.

“A lot of our work has been in the context of light and circadian rhythms,” she says. “How light affects the circadian clock, and our sleep. But that’s just one of a host of what we call ‘non-visual’ effects of light on the brain.

“In addition to impacting sleep and our circadian clock, these cells in our eyes also project to other brain areas to do with alertness and mood.”

Read more of McGlashan‘s insights into fear of the dark at