Human and macaque pupil responses driven by melanopsin-containing retinal ganglion cells

Paul D.R. Gamlin, David H. McDougal, Joel Pokorny, Vivianne C. Smith, King Wai Yau, Dennis M. Dacey

Research output: Contribution to journalArticlepeer-review

387 Scopus citations


Melanopsin, a novel photopigment, has recently been localized to a population of retinal ganglion cells that display inherent photosensitivity. During continuous light and following light offset, primates are known to exhibit sustained pupilloconstriction responses that resemble closely the photoresponses of intrinsically-photoreceptive ganglion cells. We report that, in the behaving macaque, following pharmacological blockade of conventional photoreceptor signals, significant pupillary responses persist during continuous light and following light offset. These pupil responses display the unique spectral tuning, slow kinetics, and irradiance coding of the sustained, melanopsin-derived ganglion cell photoresponses. We extended our observations to humans by using the sustained pupil response following light offset to document the contribution of these novel ganglion cells to human pupillary responses. Our results indicate that the intrinsic photoresponses of intrinsically-photoreceptive retinal ganglion cells play an important role in the pupillary light reflex and are primarily responsible for the sustained pupilloconstriction that occurs following light offset.

Original languageEnglish (US)
Pages (from-to)946-954
Number of pages9
JournalVision Research
Issue number7
StatePublished - Mar 2007


  • Human
  • Macaque
  • Melanopsin
  • Pupil
  • Pupillary

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems


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