Loading...
Afraid of the dark : Light acutely suppresses activity in the human amygdala
McGlashan, Elise M. Poudel, Govinda R. Jamadar, Sharna D. Phillips, Andrew J. K. Cain, Sean W.
McGlashan, Elise M.
Poudel, Govinda R.
Jamadar, Sharna D.
Phillips, Andrew J. K.
Cain, Sean W.
Abstract
Light improves mood. The amygdala plays a critical role in regulating emotion, including fear-related responses. In rodents the amygdala receives direct light input from the retina, and light may play a role in fear-related learning. A direct effect of light on the amygdala represents a plausible mechanism of action for light’s mood-elevating effects in humans. However, the effect of light on activity in the amygdala in humans is not well understood. 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). 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. Light, compared with dark, suppressed activity in the amygdala. Moderate light exposure resulted in greater suppression of amygdala activity than dim light. Furthermore, functional connectivity between the amygdala and ventro-medial prefrontal cortex was enhanced during light relative to dark. These effects may contribute to light’s mood-elevating effects, via a reduction in negative, fear-related affect and enhanced processing of negative emotion.
Keywords
Date
2021
Type
Journal article
Journal
PLoS ONE
Book
Volume
16
Issue
6
Page Range
1-10
Article Number
Article e0252350
ACU Department
Mary MacKillop Institute for Health Research
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
Published as ‘gold’ (paid) open access
License
CC BY 4.0
File Access
Open