Human infrared vision is triggered by two-photon chromophore isomerization

• DOI: 10.1073/pnas.1410162111
• Publication Date: 2014-12-02T04:32:27Z
• Authors: Grazyna Palczewska; Frans Vinberg; Patrycjusz Stremp...; Martin P. Bircher; David Salom; Katarzyna Komar; Jianye Zhang; Michele Cascella; Maciej Wojtkowski; Vladimir J. Kefalov; Krzysztof Palczewski
• Keywords: Chromophore; Visual phototransduction

Significance This study resolves a long-standing question about the ability of humans to perceive near infrared radiation (IR) and identifies mechanism driving human IR vision. A few previous reports our expanded psychophysical studies here reveal that can detect at wavelengths longer than 1,000 nm it as visible light, finding has not received satisfactory physical explanation. We show light activates photoreceptors through nonlinear optical process. also caused photoisomerization purified pigments model chromophore compound. These observations are consistent with quantum mechanical for energetics two-photon activation rhodopsin. Thus, via isomerization visual pigment chromophores.