Samer Hattar

Samer Hattar is a distinguished neuroscientist and circadian biologist serving as Chief of the Section on Light and Circadian Rhythms at the National Institute of Mental Health, part of the National Institutes of Health. He is internationally recognized for his groundbreaking research on how light affects the brain and body beyond vision.

Hattar's most significant contribution to science was the co-discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs), which contain the photopigment melanopsin and are responsible for non-image-forming visual functions including circadian rhythm entrainment, pupillary light reflex, and light-evoked mood regulation. His research has profound implications for understanding sleep disorders, mood disorders, and the effects of artificial light exposure on human health.