Achromatopsia, color vision, and cortex

Heywood, Charles A.

doi:10.1016/s0733-8619(02)00102-0

Cited by 37 publications

(25 citation statements)

References 74 publications

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“…To verify whether this process pertains to rods as well, we performed our visual tests on a person with documented autosomal recessive achromatopsia (ACHM) (19). This individual also perceived IR beams of 950-and 1,040-nm wavelengths.…”

Section: Resultsmentioning

confidence: 99%

Human infrared vision is triggered by two-photon chromophore isomerization

Palczewska

Vinberg

Stremplewski

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Vision relies on photoactivation of visual pigments in rod and cone photoreceptor cells of the retina. The human eye structure and the absorption spectra of pigments limit our visual perception of light. Our visual perception is most responsive to stimulating light in the 400-to 720-nm (visible) range. First, we demonstrate by psychophysical experiments that humans can perceive infrared laser emission as visible light. Moreover, we show that mammalian photoreceptors can be directly activated by near infrared light with a sensitivity that paradoxically increases at wavelengths above 900 nm, and display quadratic dependence on laser power, indicating a nonlinear optical process. Biochemical experiments with rhodopsin, cone visual pigments, and a chromophore model compound 11-cis-retinyl-propylamine Schiff base demonstrate the direct isomerization of visual chromophore by a two-photon chromophore isomerization. Indeed, quantum mechanics modeling indicates the feasibility of this mechanism. Together, these findings clearly show that human visual perception of near infrared light occurs by twophoton isomerization of visual pigments.visual pigment | two-photon absorption | rhodopsin | transretinal electrophysiology | multiscale modeling H uman vision is generally believed to be restricted to a visible light range, although >50% of the sun's radiation energy that reaches earth is in the infrared (IR) range (1). Human rod and cone visual pigments with the 11-cis-retinylidene chromophore absorb in the visible range, with absorption monotonically declining from their maxima of 430-560 nm toward longer wavelengths. The spectral sensitivity of human dim light perception matches well with the absorption spectrum of the rod visual pigment, rhodopsin (2, 3). Activation of visual pigments is temperature independent around their absorption peaks (λ max ), but at longer wavelengths, the lower energy photons must be supplemented by heat to achieve chromophore photoisomerization (4). Long wavelength-sensitive visual pigments of vertebrates exhibit maximal absorption at the ∼500-to ∼625-nm range. Pigments with λ max > 700 nm are theoretically possible, but the high noise due to spontaneous thermal activation would render them impractical (5). At human body temperature and with 1,050-nm stimulation, the sensitivity of the peripheral retina to one-photon (1PO) stimulation is less than 10 −12 of its maximum value at 505 nm (4, 6). Indeed, reports about human IR vision can be found in the literature, although they are fragmentary and do not describe the mechanism of this phenomenon.With the invention of radar during World War II, it was immediately questioned if pilots could detect high intensity radiation in the IR range of the spectrum. Wald and colleagues reported that at wavelengths above 800 nm, rod photoreceptors become more sensitive than cones, resulting in perception of IR signals as white light selectively in the peripheral retina (6). They proposed that relative spectral sensitivity declines monotonically toward longer wavele...

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Section: Resultsmentioning

confidence: 99%

Human infrared vision is triggered by two-photon chromophore isomerization

Palczewska

Vinberg

Stremplewski

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The V4 region contains two parallel visual pathways including the magnocellular and parvocellular pathways of the lateral geniculate body. Color vision is dependent on the parvocellular pathway, and stereoscopic vision depends on the magnocellular pathway [9,10,11]. Traditional models of brain function include serial or sequential processing of information.…”

Section: Discussionmentioning

confidence: 99%

“…However, most of the articles reporting on achromatopsia have been single case reports, and often concerning patients with extensive cortical lesions. A recent study on cortical damage with cerebral achromatopsia suggested that color perception developed from a stream of processing that flows through multiple visual areas, and that achromatopsia likely resulted from a lesion at one of the critical steps in the many-stage process of color perception [9,10,11]. …”

Section: Introductionmentioning

confidence: 99%

Stereopsis and Color Vision Impairment in Patients with Right Extrastriate Cerebral Lesions

Koh

Kim²,

Lee³

et al. 2008

Eur Neurol

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Background and Aim: The extrastriate cortex is a visual processing structure beyond the striate cortex. This region contains cells that differ in selectivity for different features of stimuli such as color, motion and stereopsis. We studied stereopsis and color vision in patients with right extrastriate cerebral lesions. Methods: Patients with right extrastriate cerebral lesions determined by MRI were recruited among consecutive inpatients. Patients with cognitive impairment (Mini Mental Status Examination score <24) were excluded. An ophthalmologist performed cortical visual testing: visual acuity, stereopsis, color vision and strabismus within 1 week after the insult. Results: Cortical visual testing was performed in 12 patients. Among the patients studied, 11 demonstrated abnormalities: reduced stereoacuity (8/12), color vision abnormalities (7/12). Seven patients showed complex cortical visual abnormalities. However, only 2 patients complained of subjective clinical symptoms. The MRI lesions in patients with disturbance of stereopsis were located in the dorsal occipitoparietal area and the ventral occipitotemporal area. Color vision abnormalities corresponded to lesions in the ventral occipitotemporal area. Conclusions: Patients with lesions in the right extrastriate cortex tend to have disturbance of stereopsis and color vision abnormalities, even in the absence of visual complaints.

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“…In patients with lesions of the fusiform gyrus the perception of color is abolished, although the ability to detect form remains intact 1 . It is unclear where the pathways which serve color and form begin to diverge in the visual system.…”

Section: Introductionmentioning

confidence: 99%

Orientation tuning of cytochrome oxidase patches in macaque primary visual cortex

et al. 2011

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The abundant concentration of cytochrome oxidase in patches or blobs of primate striate cortex has never been explained. Patches are thought to contain unoriented, color-opponent neurons. Lacking orientation selectivity, these cells might endow patches with a high level of metabolic activity because they respond to all contours in visual scenes. To test this idea, orientation tuning was measured in layer 2/3 of macaque V1 using acutely implanted 100-electrode arrays. Each electrode recording site was identified, and assigned to the patch or interpatch compartment. The mean orientation bandwidth of cells was 28.4° in patches and 25.8° in interpatches. Neurons in patches were indeed less orientation selective, but the difference was subtle, indicating that the processing of form and color is not strictly segregated in V1. The most conspicuous finding was that patch cells had a 49% greater overall firing rate. This global difference in neuronal responsiveness, rather than an absence of orientation tuning, may account for the rich mitochondrial enzyme activity that defines patches.

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Achromatopsia, color vision, and cortex

Cited by 37 publications

References 74 publications

Human infrared vision is triggered by two-photon chromophore isomerization

Human infrared vision is triggered by two-photon chromophore isomerization

Stereopsis and Color Vision Impairment in Patients with Right Extrastriate Cerebral Lesions

Orientation tuning of cytochrome oxidase patches in macaque primary visual cortex

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