TABLE 1.

Brain targets of ipRGCs

IpRGC Target	Target Function	IpRGC Innervation
Primary targets
Suprachiasmatic nucleus	Master regulation of circadian rhythms	Dominant
Intergeniculate leaflet	Integration of photic and nonphotic circadian cues	Major
Olivary pretectal nucleus	Pupillary constriction	Major
Posterior thalamic nucleus, dorsal border (132)	Nociception (132)	Major (132)
Lateral habenula	Integration of limbic, motor, and circadian systems	Undetermined
Secondary targets
Dorsal lateral geniculate nucleus	Image-forming vision	Minor
Lateral hypothalamus	Energy homeostasis	Minor
Lateral posterior thalamic nucleus	Higher-order processing of thalamic, cortical, and visual signals	Moderate
Posterior limitans thalamic nucleus	Detection of rapid illumination changes for nonimage vision	Moderate
Superior colliculus	Integration of multiple modalities for gaze control	Minor
Ventral lateral geniculate nucleus	Visuomotor function	Minor
Ventral subparaventricular zone	Circadian and direct regulation of locomotion and sleep	Minor
Ventrolateral preoptic nucleus	Promotion of sleep	Minor

Selected brain regions innervated by intrinsically photosensitive retinal ganglion cells (ipRGCs) are listed with their general function (for a more comprehensive survey, see Refs. 63 and 87). Targets receiving dense innervations by ipRGC fibers are grouped at the top of the table, and others receiving weaker innervations are listed below in alphabetical order. IpRGC innervation refers to the density of ipRGC afferents relative to that of conventional RGCs. IpRGC innervation is predominantly contralateral for all regions except the SCN, which is largely bilateral. This list is not exhaustive. It is also likely to concern mostly the M1 ipRGCs, and other ipRGC subtypes may have different projections (see text). [Modified and updated from Fu et al. (54).]