Detection probabilities for wavelength changes were measured as functions of stimulus onset asynchrony (SOA) with the chromatic double-pulse method. Two test stimuli of a wavelength lambda t were successively exchanged with a reference stimulus of a wavelength lambda r in equal luminance for a short duration with a SOA. Durations ...

The spectral sensitivity of 15 species of birds has been measured by recording transretinal voltages from opened eyecups. With suitable combinations of colored adapting lights, we find that a variety of passerines have four peaks of photopic sensitivity, with maxima at 370, 450, 480, and 570 nm. Additional sensitivity maxima ...

This study reports photopic spectral sensitivity curves (351-709 nm) for four individual roach, Rutilus rutilus, determined by two choice appetitive training. All four curves show four sensitivity maxima at 361-398 nm, 421-448 nm, 501-544 nm and 634-666 nm which are related to the four known roach photopic visual pigments (Avery ...

Three subjects viewed, foveally and monocularly, a monochromatic test field of 0.6-deg diameter that was surrounded by a white annulus of 0.6-deg inner diameter and 4.5-deg outer diameter. The wavelength of the central test field was varied in steps of 10 nm from 440 to 640 nm, and its luminance ...

We determined the effect of introducing errors in refractive correction on the threshold retinal sensitivity in the central 6 degrees of the visual field in 11 normal subjects using automated static perimetry (Octopus program 62). A summated value of threshold retinal sensitivity was computed for each visual field by taking ...

Early in life, abnormal visual experience may disrupt the developmental processes required for the maturation and maintenance of normal visual function. The effects of retinal image deprivation (monocular form deprivation) on four psychophysical functions were investigated in rhesus monkeys to determine if the sensitive period is of the same duration ...

Intracellular recordings were made from axon bearing horizontal cells in isolated retinas (with retinal pigment epithelium removed) of normal and pearl mutant mice superfused with mammalian Ringer's solution. Cells were injected with Lucifer yellow and identified by their morphology and their response wave-forms. On impalement, we measured a dark, resting ...

We sought to measure the mechanisms underlying the perception of blackness in the following way. A central spot (45') of fixed luminance was surrounded by a dark ring (7.5'), and surrounding all was an annular zone (30') of light. This stimulus was presented in Maxwellian view for 0.5 sec every ...

Spectral sensitivity functions and the transient decrease of sensitivity to short wavelengths after the offset of yellow light (transient tritanopia) were measured by increment threshold techniques in patients suffering from hereditary macular degenerations. Color vision defects were determined by arrangement tests and the anomaloscope. Central areolar choroidal dystrophy was found ...

The retina of the tree shrew (Tupaia belangeri) is heavily cone dominated, rods comprising less than 4% of the total photoreceptors. Spectral mechanisms and color vision were investigated in this species in both behavioral and electrophysiological experiments. In confirmation of an earlier investigation, the tree shrew was found to have ...

The 2-month-old human infant is known to be less visually sensitive than the adult by a factor of 50, if sensitivity is measured by the threshold for detecting a test light in the dark. In the present experiment, visual sensitivity of infants and adults did not differ significantly when sensitivity ...

The relative spectral sensitivity of blue-sensitive pigeon cones was determined using flicker-photometry based on mass ERG-responses from intact subjects during high-level light adaptation. The resulting spectral sensitivity curve can be mimicked by a P460 nomogram screened by an oil-droplet that absorbs 50% at 466 nm. Comparison of the curve with ...

Spectral and polarization sensitivities of blowfly R1-6 photoreceptor cells were measured by intracellular recordings in cells which differed in visual pigment content. The spectral sensitivity in the visible wavelength range can be quantitatively explained from the absorption spectrum of blowfly visual pigment when the waveguide properties of the rhabdomere are ...

Spectral luminous efficiency functions for mesopic vision were measured extensively to establish a basic data set for the mesopic photometry system. These functions were obtained by the direct brightness matching for a 10 degrees field at nine retinal illuminance levels from 100 to 0.01 Td in 0.5-log-unit steps. Data for ...

Psychophysical methods developed for the investigation of spatial and temporal pathways in human vision have been applied in combination with the two-colour increment threshold technique of W. S. Stiles to study the way in which signals from blue-sensitive cones are transmitted along the visual pathways. A flicker sensitive spatio-temporal filter, ...

Visual sensitivity of optic tectum-ablated goldfish was investigated using a classical conditioning technique. Intact fish were screened to obtain individuals which showed suppression of breathing movements in response to the visual conditioned stimulus (CS) in the presence or absence of adapting illumination. Following bilateral optic tectum ablation, responding was blocked ...

Data for three fundamental psychophysical functions (spatial modulation sensitivity, temporal modulation sensitivity, and increment-threshold spectral sensitivity) were compared for groups of 12 rhesus monkeys and 12 human subjects. It was found that there are important, nontrivial differences between the data for monkeys and humans, but that many of the differences ...

Spectral sensitivity of the cichlid fish Haplochromis burtoni was measured under both scotopic and photopic conditions using a two-choice, food reward, operant conditioning paradigm. The highest absolute sensitivity (scotopic) is one quantum for every 5 to 50 rods measured at 475 nm (equivalent to a corneal irradiance of 3.8 x ...

The effect of tinted flexible contact lenses on light sensitivity and photophobic response has often been questioned but never thoroughly investigated. An Alpascope was used to investigate whether tinted hydrogel contact lenses would relieve glare sensitivity in pre-adapted contact lens wearers. Various densities of sky blue and autumn amber Cibasoft ...

The possible role of Ca ions in mediating the drop in sensitivity associated with light adaptation in Limulus ventral photoreceptors was assessed by simultaneously measuring the sensitivity to light and the intracellular free Ca concentration (Cai); the latter was measured by using Ca-selective microelectrodes. In dark-adapted photoreceptors, the mean resting ...

Spectral sensitivity was measured in the light adapted state for two individuals (S1 and S2) of Pseudemys scripta elegans using a behavioral training technique. The curves have three pronounced maxima at 450 nm, at 570 nm (S1) or 540 nm (S2), and at 640 nm. The spectral sensitivity functions can ...

Pupillomotor and sensory spectral sensitivity curves of light-adapted eyes were compared. Experimental conditions were designed to favor (despite the threshold criterion) opponent processing of signals: long (500-ms) stimuli of large diameter (60 degrees) were presented centrally on an intense (16 cd/m2) white background. Narrow spacing of monochromatic stimuli permitted the ...

The spectral sensitivities of red-, green-, and blue-sensitive cones were measured by intracellular recording in the carp retina. The responses from all cones were univariant, i.e., the waveform of a response to any wavelength and at any intensity could be superimposed on the response to other wavelengths if the intensity ...

The corneal electroretinogram (ERG) was used to investigate the spectral sensitivities of cones in 12 dichromatic squirrel monkeys (Saimiri sciureus) whose color-vision capacities were established in behavioral tests. Three different varieties of dichromacy were represented among these animals. A flicker-photometric procedure was used in which the ERG response to a ...

It has been shown, or inferred, in various contexts that radiosensitization of cells by oxygen is the sum of two (or more) components. If the component sensitivities conform with the Alper and Howard-Flanders equation their sum cannot also conform, but, in practice, even the most meticulous experimental techniques will fail ...

Two kinds of afferents in the posterior lateral line nerve in catfish have been identified according to their functional properties: the electro- and mechanoreceptor afferents. The electroreceptor afferents are very sensitive to electric current in water. They do not respond to distant mechanical stimulation resulting from water dropping into the ...

Flicker-photometric spectral sensitivity is measured in the presence and absence of superimposed monochromatic surrounds. Although color appearance depends on surround wavelength, the shape of the flicker-spectral-sensitivity functions are unaffected. These findings indicate both a lack of cone-cone inhibition within the achromatic channel and independence of the achromatic and chromatic channels.

We propose the use of a touch-sensitive screen as a tool to facilitate acquisition of data both in point counting and morphometric planimetry. It obviates the use of a 'correspondence image' required with many planimetric devices in which the means for data acquisition and display are separate. The touch-sensitive screen ...

Spectral sensitivity and wavelength discrimination are determined along the nasal horizontal meridian of the human peripheral retina. The target size as a function of eccentricity is varied according to a particular cortical magnification factor. Spectral sensitivity is measured by flicker photometry parameterized for the flicker frequency (10-20 Hz) and is ...

Male Bobwhite quail (Colinus virginianus) (N:5) were initially handled, then trained upon hearing a 1.5-kc/s tone of 3-sec duration to approach a feeder-loudspeaker system and peck a response key for food reinforcement. Threshold testing in subsequent sessions using a method of limits established the species' audibility curve over 11 frequencies ...

The development of rod and cone function was studied in late embryonic and posthatch chicks by measuring the spectral sensitivity of the electroretinogram (ERG) of opened eyecups to 100-msec flashes and 25-Hz stimuli. At the time of hatching the ERG is dominated by cone activity: the response-energy curves for different ...

There is disagreement as to how closely the properties of the pathways that detect small spots resemble the properties of the achromatic system. Spectral sensitivities for small, brief lights show a single, relatively broadband peak similar to the achromatic spectral sensitivity. The lights also appear relatively desaturated near threshold. However, ...

Spectral sensitivity was measured in freely moving, light adapted goldfish using a behavioral training technique. The curve reveals 3 pronounced maxima at 470, 540 and 660 nm. Compared with the absorption spectra of the cone photopigments with lambda max at 450, 530 and 625 nm, the maxima were much narrower ...

Direct absorbance and bleaching absorbance-difference spectra were obtained using a photon-counting microspectrophotometer from the outer segments of ten blue-sensitive cones of macaque monkeys. The peak wavelength (lambda max) of the direct measurements was 426 +/- 3.4 nm, whereas the lambda max of the bleaching difference was 434 +/- 6.6 nm. ...

This relatively inexpensive device has been helpful not only for wheelchair-bound patients, such as individuals with spinal cord injuries, but also for other persons with minimal motor strength and control. In this case study, a patient with no control over conventional light fixtures could use the touch-sensitive relay and control ...

We studied the relationship between light intensity and cell response to various wavelengths and wavelength combinations in the dorsal, parvocellular layers of the macaque lateral geniculate nucleus. When response is plotted as a function of the logarithm of stimulus intensity, the slope and shape of curves depends on wavelength. For ...

PIII and b-wave spectral sensitivity functions were measured under various adapted conditions in the 13-lined ground squirrel. The PIII was isolated by intravitreal injection of sodium L-aspartate. Under the conditions studied, the PIII spectral sensitivity function always fitted the absorption spectrum of a 518 +/- 3 mm Dartnall nomogram. This ...

The photopic spectral sensitivity of the rainbow trout, Salmo gairdneri, was determined using a two choice appetitive training method. The resulting curve had three maxima at around 391-473, 490-573 and 650-669 nm. Maximum sensitivity was reached with short wavelength stimuli. Thresholds for white light were also obtained. The results show ...

1. Intracellular voltage and current responses to short (blue) and long (red) wave-length lights were measured in the distal hyperpolarizing photoreceptor (;off receptor') of the isolated and perfused scallop (Pecten irradians) retina.2. The early receptor potential (e.r.p.) was isolated by holding membrane potential at the reversal potential for the late ...

To investigate whether static and dynamic sensitivities of slowly and rapidly adapting stretch receptor organs (SAO and RAO, respectively) or crayfish are different when perturbed compared with those in conventional laboratory experiments, receptors were submitted to ramplike length changes of different velocities separated by long-duration, constant lengths of different values. ...

Field sensitivities of the three IIj (j = 3, 4, 5) mechanisms of Stiles were measured for monochromatic backgrounds of different wave numbers (mu)-1 traversing the eye through different points (r) displaced along a horizontal chord through the centre of the entrance pupil. Each mechanism shows an insensitivity to the ...

By means of visual stimnulus without temporal or spatial edges, we have achieved better isolation of chromatic signals at detection threshold than has been reported previously. Under various states of adaptation, the spectral sensitivity of the chromatic mechanism detecting middle- and long-wavelength lights corresponds with that deduced from suprathreshold red/green ...

It has been shown that for human foveal vision the test spectral sensitivity curve obtained in the presence of a large white background exhibits peaks at about 440, 530 and 610 nm and a small dip or notch at about 580 nm. Additionally, field spectral sensitivity curves for the medium- ...

The luminance of a large diffuse field, viewed peripherally, was temporally modulated near absolute detection threshold. The field luminance either increased abruptly and decreased gradually (ON stimulus) or increased gradually and decreased abruptly (OFF stimulus). For all wavelengths shorter than 620 nm, sensitivity to the ON stimulus was greater than ...

Earlier observations suggested there might be significant within-species variations in visual sensitivity among squirrel monkeys (Saimiri sciureus). Reported here are the results from measurements of increment-threshold spectral sensitivity in 41 squirrel monkeys of Peruvian origin. As determined in a forced-choice discrimination task, no large variations were found among these animals ...

The absolute threshold of the dark-adapted retina for a 1 degree circular white light stimulus located at 15 degrees eccentric to the fovea was measured on four meridians. In each of the 11 tested subjects the sensitivity was found to be higher on the 90 degrees suprafoveal vertical meridian, on ...

Reflectance spectrophotometry analysis has been applied to the human nasal mucosa in vivo to determine the objective parameters of the colors of the mucous membrane, as well as to study the hemodynamics and enzymatic activities related to respiratory chain metabolism in the nasal mucosa. In 24 normal subjects, there were ...

1. The organization of the receptive fields of retinal ganglion cells in te normal mouse was studied qualitatively in recordings from 43 single axons in the optic nerve and optic tract, and the light sensitivity was studied quantitatively in 26 of these cells by measuring incremental sensitivity. 2. The receptive ...

Mutant Halobacterium halobium strains deficient in all previously reported rhodopsin-like pigments show phototaxis responses comparable to those of wild-type strains. Spectroscopic analysis reveals the presence of a third retinal-containing pigment in the cells and their membrane fractions. It undergoes a photoreaction cycle with a half-time of approximately equal to 1 ...

Exposure to noise might be responsible for a wide and varied spectrum of physical and mental morbidity, although many of the claims of cause and effect relationship are controversial and unproven. The etiological relationship between noise and high frequency hearing loss is, however, well documented. While noise-induced hearing loss is ...