Summary
This study confirms that PACAP-immunoreactive projections serve as a reliable anatomical marker for ipRGC central projections in macaque monkeys, mapping their targets across brain regions involved in circadian entrainment, pupillary light reflex, and other non-image-forming functions. These findings provide a primate-relevant anatomical foundation for understanding how light signals from melanopsin-containing cells reach the SCN and other brain structures, informing the biological basis for circadian lighting design.
Key Findings
- PACAP and melanopsin were co-stored in 99% of melanopsin-expressing retinal ganglion cells in the macaque retina.
- ipRGC projections (identified by co-localized CtB and PACAP staining) were confirmed in the SCN, lateral geniculate complex, pregeniculate nucleus, pretectal olivary nucleus, nucleus of the optic tract, brachium of the superior colliculus, and superior colliculus.
- Both inner and outer stratifying melanopsin RGC subtypes were confirmed to co-express PACAP, supporting PACAP as a broad marker for ipRGC projections in primates.
Categories
The Science of Light: Characterizes ipRGC central projections in primate brain using PACAP as a marker, mapping the neural architecture underlying non-image-forming light responses including circadian entrainment and pupillary reflex.
Sleep & Circadian Health: Identifies retinal projection targets including the SCN relevant to circadian entrainment by melanopsin-expressing ipRGCs in a primate model.
Author(s)
JA Treffalls, KQ Chang
Publication Year
2017
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The two‐process model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors