The schematic eye in the cat

Vakkur, G.J.; Bishop, Peter

doi:10.1016/0042-6989(63)90009-9

Cited by 146 publications

(42 citation statements)

References 20 publications

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“…In such eyes, the lens is thick, in some cases almost spherical. Furthermore, its centre is close to the centre of curvature of the cornea (Vakkur and Bishop, 1963;Hughes, 1979;Campbell et al, 1982;Martin, 1983;Remtulla and Hallett, 1985). Asymmetrical aberrations should therefore play a minor role.…”

Section: The Origin Of Ring-like Structures In Videorefractive Imagesmentioning

confidence: 94%

Pupil shapes and lens optics in the eyes of terrestrial vertebrates

Malmström

Kröger

2006

Journal of Experimental Biology

103

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SUMMARY Animal eyes that are primarily used under low-light conditions usually have optical systems of short depth of focus, such that chromatic defocus may lead to considerable blurring of the images. In some vertebrates, the problem is solved by multifocal lenses having concentric zones of different focal lengths, each of which focuses a different relevant spectral range onto the retina. A partially constricted circular pupil would shade the peripheral zones of the lens, leading to the loss of well-focused images at relevant wavelengths. The slit pupil, however, allows for use of the full diameter of the lens even in bright light. We studied species of terrestrial vertebrates from a variety of phylogenetic groups to establish how widespread multifocal lenses are and how pupil shapes are adapted to the optical systems. We found that multifocal lenses are common from amphibians to mammals, including primates. Slit pupils were only present in animals having multifocal optical systems. Among the felids, small species have multifocal lenses and slit pupils, while large species have monofocal lenses and round pupils. The Eurasian lynx, a cat of intermediate size, has an intermediate eye design. The functional significance of the absence of multifocal optical systems in large felids remains mysterious, because such systems are present in other large-eyed terrestrial vertebrates. Multifocal optical systems in nocturnal prosimians suggest that those animals have colour vision despite being described as cone monochromats.

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Section: The Origin Of Ring-like Structures In Videorefractive Imagesmentioning

confidence: 94%

Pupil shapes and lens optics in the eyes of terrestrial vertebrates

Malmström

Kröger

2006

Journal of Experimental Biology

103

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“…The references for these values were mainly derived from the study by Heesy (2004), his Table 1. Human (Vakkur and Bishop, 1963); macaque (Vakkur and Bishop, 1963;Ross, 1995); owl monkey (Allman and McGuinness, 1988); marmoset (Cartmill, 1971;Fritsches and Rosa, 1996); cat (Hughes, 1976;Arrese et al, 1999;Finarelli and Goswami, 2009); ferret (Garipis and Hoffmann, 2003); tree shrew (Hughes, 1977); squirrel (Kaas et al, 1972;Van Hooser et al, 2005); rat (Arrese et al, 1999); mouse (Dräger, 1978;Arrese et al, 1999); rabbit (Wall, 1942;Hughes and Vaney, 1982); barn owl (Iwaniuk et al, 2008); pigeon (Iwaniuk et al, 2008). more prominent at lower speeds because of the specific spatiotemporal bandwidth of visual neurons.…”

Section: Lack Of Orientation Maps Despite Orientation Selectivitymentioning

confidence: 99%

Dominant Vertical Orientation Processing without Clustered Maps: Early Visual Brain Dynamics Imaged with Voltage-Sensitive Dye in the Pigeon Visual Wulst

Ng¹,

Grabska-Barwińska²,

Güntürkün³

et al. 2010

J. Neurosci.

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The pigeon is a widely established behavioral model of visual cognition, but the processes along its most basic visual pathways remain mostly unexplored. Here, we report the neuronal population dynamics of the visual Wulst, an assumed homolog of the mammalian striate cortex, captured for the first time with voltage-sensitive dye imaging. Responses to drifting gratings were characterized by focal emergence of activity that spread extensively across the entire Wulst, followed by rapid adaptation that was most effective in the surround. Using additional electrophysiological recordings, we found cells that prefer a variety of orientations. However, analysis of the imaged spatiotemporal activation patterns revealed no clustered orientation map-like arrangements as typically found in the primary visual cortices of many mammalian species. Instead, the vertical orientation was overrepresented, both in terms of the imaged population signal, as well as the number of neurons preferring the vertical orientation. Such enhanced selectivity for the vertical orientation may result from horizontal motion vectors that trigger adaptation to the extensive flow field input during natural behavior. Our findings suggest that, although the avian visual Wulst is homologous to the primary visual cortex in terms of its gross anatomical connectivity and topology, its detailed operation and internal organization is still shaped according to specific input characteristics.

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“…From 1 to 250 cycles of grating were displayed on the tube face, corresponding to the spatial frequency range 0-03-8-2 eycles/deg. The display tube was carried on a gimbal which rotated about the anterior nodal point of the eye (9 mm posterior to the corneal pole: Vakkur & Bishop, 1963) and the orientation of the visual stimulus was controlled by rotation of a Dove prism, also carried on the gimbal. The mid point of the 7-5 cm reflecting face of the prism was located 5-5 cm from the nodal point of the eye, leaving just enough room to accommodate the artificial pupil and spectacle lenses.…”

Section: Visual 8timulu8mentioning

confidence: 99%

Analysis of orientation bias in cat retina

Levick

Thibos

1982

The Journal of Physiology

204

153

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SUMMARY1. Responses of cat retinal ganglion cells to a drifting sinusoidal grating stimulus were measured as a function of the grating orientation and spatial frequency.2. The response at fixed frequency and contrast varied with orientation in the manner of a cosine function. A new measure was introduced to quantify this orientation bias in the response domain on an absolute scale of 0-100 %. Under experimental conditions designed to maximize the effect, the mean bias for 250 cells was 16% and the range was 0-46%. In 70 % of cells there was significant bias.3. Orientation bias varied with spatial frequency and was maximal near the high-frequency limit. The majority of biassed cells preferred the same orientation at high and low frequencies but in some cells a reversal occurred: the orientation which gave maximum response at high frequencies gave minimum response at low frequencies. The greatest variation of cut-off frequency with orientation was I octave.4. Orientation bias was due to neural, not optical, factors. Nevertheless, the phenomenon could often be imitated by deliberately introduced optical astigmatism of up to 4 dioptres for brisk-sustained units and over 10 dioptres for brisk-transient units.

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The schematic eye in the cat

Cited by 146 publications

References 20 publications

Pupil shapes and lens optics in the eyes of terrestrial vertebrates

Pupil shapes and lens optics in the eyes of terrestrial vertebrates

Dominant Vertical Orientation Processing without Clustered Maps: Early Visual Brain Dynamics Imaged with Voltage-Sensitive Dye in the Pigeon Visual Wulst

Analysis of orientation bias in cat retina

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