Image quality of the cat eye measured during retinal ganglion cell experiments

Abstract

SUMMARY1. The modulation transfer function (MTF) of the dioptrics of fifteen cat eyes was determined. The aerial image, formed by the eye of a standard object (a 0-5-1-0°annulus), was photographed. The transmission of the film negative was measured with a scanning microdensitometer to yield the light distribution within the aerial image. Correcting for the double passage, this experimentally determined light distribution and the known object light distribution were used to obtain the MTF, applying Fourier methods. Each MTF was used to calculate the light distribution within the retinal image of stimuli of various geometry used in experiments on retinal ganglion cells in the same eye.2. When the eye was equipped with an artificial pupil of the same size as that used in the neurophysiological experiments (4.0-4.8 mm diam.) the MTF had fallen to 0 5 at 2-43 c/deg. When the pupil was removed the MTF had fallen to 0 5 at a much lower spatial frequency (1.0 c/deg). This shows that even when one uses an artificial pupil too large to provide optimal image quality there is a vast improvement over using no pupil.3. These image quality measurements were prompted by the need to know the actual stimulus image in experiments on the functional organization of the receptive field, a need exemplified in this paper by a few specific physiological results. The full neurophysiological results appear in the next two papers.

Behavioural contrast sensitivity of the cat in various visual meridians

“…It rather means that he uses another range of spatial frequencies, most probably matched to the distance at which the visual world appears to the cat more relevant. This point and the possible limits introduced by the optics of the eye (Bonds, 1972;Bonds, Enroth-Cugell & Pinto, 1972;Wissle, 1971;Wassle & Creutzfeldt, 1973) have been thoroughly discussed in a previous paper (Campbell et al 1973).…”

Properties of the surround response mechanism of cat retinal ganglion cells and centre‐surround interaction

“…S2 also delivered the 0-5-1°diam. annulus whose aerial image was photographed (Bonds et al 1972). In most experiments the third source (S3) provided a 120 diam.…”

“…After the lens had been applied to the eye the pupil was cleaned with a special solution for front surface mirrors. The contact lens power for best retinal focus was chosen as described in the previous paper (Bonds, Enroth-Cugell & Pinto, 1972). The stimulator (Fig.…”

Lateral spread of light adaptation in the rat retina

“…However, Boynton and Whitten (1970) used the ' A preliminary report of these results (Green and Tong, 1975) was presented to the annual meeting of ARVO, April, 1975. receptor potential of the monkey fovea to show that an adapting background causes primate cones to change their sensitivity. Other experiments, using sodium asparate to isolate receptor potentials, have provided ample evidence that skate rods (Dowling and Ripps, 1972), goldfish rods and cones (Witkovsky, Nelson, and Ripps, 1973), and frog rods and cones (Hood and Hock, 1973;Hood, Hock and Grover, 1973) display the full range of adaptive phenomena.…”