Jack B. Calderone
University of California, Santa Barbara
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Featured researches published by Jack B. Calderone.
Visual Neuroscience | 1995
Jack B. Calderone; Gerald H. Jacobs
About 3% of all mouse photoreceptors are cones. An earlier electrophysiological study indicated that there were two classes of cone in the mouse retina having peak sensitivities (lambda max) of about 360 nm and 511 nm. Recent immunocytochemical results show there are two types of cones that have distinctive regional segregation patterns. We used regional stimulation of the retina in conjunction with electroretinogram (ERG) flicker photometry to see if the two cone types identified electrophysiologically are regionalized in a fashion suggested by the anatomical results. We find they are. Relative sensitivity to ultraviolet and visible light stimulation qualitatively parallels that predicted by immunocytochemical labelling. One result of this remarkable regionalization of cone types is that the mouse retina is relatively more sensitive to ultraviolet light stimulation when that light is directed toward the ventral half of the retina.
Visual Neuroscience | 1999
Jack B. Calderone; Gerald H. Jacobs
Results from earlier experiments indicate that different species of rodent vary both in the number of cone types found in their retinas and in the spectral sensitivities of the cone pigments. These features have now been examined in two types of hamster commonly used for research purposes: Syrian golden hamsters (Mesocricetus auratus) and Siberian dwarf hamsters (Phodopus sungorus). Electroretinogram (ERG) flicker photometry, behavioral discrimination tasks, and opsin antibody labeling were used to investigate hamster photoreceptors and their visual consequences. Results from the three approaches support the following conclusions: (1) The retinas of both species have an abundant population of rods containing a photopigment with peak sensitivity of about 498-500 nm; (2) Siberian dwarf hamsters have two classes of cone: one with maximum sensitivity in the ultraviolet (c. 360 nm), the other with peak sensitivity closely similar to that of its rod; and (3) Syrian golden hamsters have a class of cone with peak sensitivity at about 506 nm, but they lack a second cone type. Implications of these alternative arrangements are discussed.
Brain Behavior and Evolution | 2003
Jack B. Calderone; Benjamin E. Reese; Gerald H. Jacobs
The spatial distributions of photoreceptors and retinal ganglion cells were examined in the spotted hyena (Crocuta crocuta). Two populations of cones were identified by immunocytochemical labeling. The hyena retina contains approximately 2.3 million middle- to long-wavelength sensitive (M/L) cones that reach peak densities of about 7,500/mm2 in the vicinity of the optic nerve head. A sparser population of short-wavelength sensitive (S) cones, totaling about 0.3 million, was also detected. There is a striking disparity in the spatial distributions of the two cone types with S cones achieving peak density in a region located well below the optic nerve head. The differences in the spatial distributions of the two cone types have implications both for visual sensitivity and for color vision. Hyena rods outnumber cones by about 100:1 with rod density falling off modestly along a central-peripheral gradient. Ganglion cells were identified in retinal wholemounts by Nissl staining patterns. Their distribution defines a prominent visual streak with highest spatial packing (approx. 4,200/mm2) in an area centralis that is located in the temporal retina. The total number of ganglion cells is estimated at about 260,000. Using standard assumptions the maximum spatial resolution of the spotted hyena is calculated to be about 8.4 cycles/degree, a value similar to estimates obtained for other terrestrial carnivores.
Visual Neuroscience | 2003
Jack B. Calderone; Gerald H. Jacobs
The spectral mechanisms of the ferret (Mustela putorious furo) were studied with electroretinogram (ERG) flicker photometry. Variations in adaptation state and flicker rate were used to define corneally based spectral sensitivities for the three classes of receptor present in the retina of this mustelid-rods (lambdamax = 505 nm), S cones (430 nm), and L cones (558 nm). The retinal distributions of the two classes of cone were determined using opsin antibody labeling. Ferret retinas contain a total of about 1.3 million cones with L cones outnumbering S cones in a ratio of approximately 14:1. ERGs were also recorded using 18.75-Hz flickering stimuli that were designed to isolate signals from individual cone classes. The contrast/response functions for signals originating from both S and L cones were linear over low-to-moderate levels of contrast, but with greatly different slopes for the two cone types. The L:S contrast gain ratio derived from a comparison of these slopes, as well as inferences drawn from another experiment in which responses to various combinations of L- and S-cone activation were analyzed, suggest that contributions of these two cone types to the flicker ERG have a relative weighting of about 4:1 to 5:1 (L/S).
Documenta Ophthalmologica | 2002
Gerald H. Jacobs; Jack B. Calderone; Tsutomu Sakai; Geoffrey P. Lewis; Steven K. Fisher
In people, retinal detachment often leads to a significant loss in cone-based vision. Most of the animal models commonly used for studying the consequences of retinal detachment have rod-dominated retinas. The purpose of this investigation was to evaluate the possibility that the ground squirrel, a rodent with a heavily cone-dominated retina, might provide a useful model for studying cone function in retinal detachment. Corneal ERGs were recorded from ground squirrels for large-field temporal modulations presented on a computer-controlled color monitor. Modulations were chosen to selectively stimulate either of the two classes of cone found in the ground squirrel retina. Under these test conditions, large and reliable cone ERGs could be readily recorded. In animals in which the retina had been surgically detached, the loss of cone signal was directly related to the number of cones in the detachment zone relative to the total cone population and that relationship did not differ for short-wavelength sensitive (S) and middle-wavelength sensitive (M) cones. Surgical reattachment produced a progressive recovery of cone-based signals. The ground squirrel seems likely to provide a useful animal model for studying the dynamics of cone function in retinal detachment and subsequent events.
9th Congress of the International Colour Association | 2002
Yasuki Yamauchi; David R. Williams; David H. Brainard; Austin Roorda; Joseph Carroll; Maureen Neitz; Jay Neitz; Jack B. Calderone; Gerald H. Jacobs
Unique yellow is considered to represent the equilibrium point of the red-green opponent chromatic mechanism. There are several hypotheses that attempt to explain how this equilibrium point is established. The determinant for unique yellow, however, has not yet been clarified. Here we explored whether the L/M cone ratio or visual information determines unique yellow. If the former is the case, we expect that subjects with large differences in their L/M cone ratio would set different spectral lights to appear as unique yellow. The results of such an experiment, however, did not show a substantial difference in the value of unique yellow for two subjects with very different cone ratios. On the other hand, if the latter is the case, unique yellow should change when altering the chromaticity of the surrounding visual environment. To test this hypothesis, we conducted long-term adaptation experiments, in which subjects spent 8 to 12 hours in a chromatically altered environment. A significant shift of unique yellow was observed after spending time in such an environment for several days. These results indicate that the red-green opponent channel includes a plastic normalization mechanism that adjusts its balance point based on visual experience.
Journal of the Optical Society of America | 2000
David H. Brainard; Austin Roorda; Yasuki Yamauchi; Jack B. Calderone; Andrew B. Metha; Maureen Neitz; Jay Neitz; David A. Williams; Gerald H. Jacobs
Investigative Ophthalmology & Visual Science | 2003
Tsutomu Sakai; Jack B. Calderone; Geoffrey P. Lewis; Kenneth A. Linberg; Steven K. Fisher; Gerald H. Jacobs
The Journal of Neuroscience | 1999
Gerald H. Jacobs; John C. Fenwick; Jack B. Calderone; Samir S. Deeb
Investigative Ophthalmology & Visual Science | 1999
David H. Brainard; Jack B. Calderone; Alexander K. Nugent; Gerald H. Jacobs