Furthermore, functional connectivity between the amygdala and ventro-medial prefrontal cortex was enhanced during light relative to dark.
Moderate light exposure resulted in greater suppression of amygdala activity than dim light. Light, compared with dark, suppressed activity in the amygdala. Participants were exposed to alternating 30s blocks of light (10 lux or 100 lux) and dark (<1 lux), with each light intensity being presented separately. We examined the effect of passive dim-to-moderate white light exposure on activation of the amygdala in healthy young adults using the BOLD fMRI response (3T Siemens scanner n = 23). However, the effect of light on activity in the amygdala in humans is not well understood. A direct effect of light on the amygdala represents a plausible mechanism of action for light’s mood-elevating effects in humans. In rodents the amygdala receives direct light input from the retina, and light may play a role in fear-related learning. The amygdala plays a critical role in regulating emotion, including fear-related responses.
