The grain of the retina becomes progressively coarser from the fovea to the periphery. This is caused by the decreasing number of retinal receptive fields and decreasing amount of cortex devoted to each degree of visual field (= cortical magnification factor) as one goes into the periphery. We simulate this with a picture that is progressively blurred towards its edges; when strictly fixated at its centre it looks equally sharp all over.
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References
1.
AnstisS M, 1974“A chart demonstrating variations in acuity with retinal position”Vision Research14589–592
2.
AnstisS M, 1996“Adaptation to peripheral flicker”Vision Research363479–3485
3.
AnstisS MHarrisJ P, 1987“Magnification factor for adaptation of a visual transient mechanism”Journal of the Optical Society of America A41688–1698
4.
BijlPKoenderinkJ JKappersA M, 1992“Deviations from strict M scaling”Journal of the Optical Society of America A91233–1239
5.
CoweyARollsE T, 1974“Human cortical magnification factor and its relation to visual acuity”Experimental Brain Research21447–454
6.
CurcioCAllenK A, 1990“Topography of ganglion cells in human retina”Journal of Comparative Neurology3005–25
7.
CurcioCSloanK RKalinaR EHendersonA, 1990“Human photoreceptor topograph”Journal of Comparative Neurology292497–523
8.
DanielMWhitteridgeD, 1961“The representation of the visual field on the cerebral cortex in monkeys”Journal of Physiology (London)159203–221
9.
De ValoisR LDe ValoisK K, 1988Spatial Vision (New York: Oxford University Press)
10.
DobelleW HTurkeiJHendersonD CEvansJ R, 1974“Mapping the representation of the visual field by electrical stimulation of human visual cortex”American Journal of Ophthalmology88727–735
11.
DrasdoN, 1977“The neural representation of visual space”Nature (London)266554–555
12.
DrasdoN, 1989“Receptive field densities of the ganglion cells of the human retina”Vision Research29985–988
13.
DrasdoNFowlerC W, 1974“Non-linear projection of the retinal image in a wide-angle schematic eye”British Journal of Ophthalmology58709–714
14.
van EschJ AKoldenhofE Evan DoornA JKoenderinkJ J, 1984“Spectral sensitivity and wavelength discrimination of the human peripheral visual field”Journal of the Optical Society of America A1443–450
15.
FoxP TMiezinF MAllmanJ MVan EssenD CRaichleM E, 1987“Retinotopic organization of human visual cortex mapped with positron-emission tomography”Journal of Neuroscience7913–922
16.
van de GrindW Avan DoornA JKoenderinkJ J, 1983“Detection of coherent movement in peripherally viewed random-dot patterns”Journal of the Optical Society of America731674–1683
17.
GrüsserO-J, 1995“Migraine phosphenes and the retino-cortical magnification factor”Vision Research351125–1134
18.
HainesR FKiefelS M, 1988“Vertical displacement threshold sensitivity along the horizontal meridian as a function of stimulus rate, duration, and length”Aviation, Space, & Environmental Medicine59321–329
19.
HamptonD RKerteszA E, 1983“The extent of Panum's area and the human cortical magnification factor”Perception12161–165
20.
von HelmholtzH, 1910/1962Treatise on Physiological Opticsvolume 3 (New York: Dover, 1962); English translation by SouthallJ P C, for the Optical Society of America (1925) from the 3rd German edition of Handbuch der physiologischen Optik (Hamburg: Voss, 1910), figure 22, page 181
21.
HessR FPointerJ SWattR J, 1989“How are spatial filters used in fovea and parafovea?”Journal of the Optical Society of America A6329–339
22.
HubelD HWieselT N, 1974“Uniformity of monkey striate cortex: A parallel relationship between field size, scatter and magnification factor”Journal of Comparative Neurology158296–306
23.
JamarJ HKwakmanL FKoenderinkJ J, 1984“The sensitivity of the peripheral visual system to amplitude modulation and frequency modulation of sine-wave patterns”Vision Research24243–249
24.
JohnstonAWrightM J, 1983“Visual motion and cortical velocity”Nature (London)304436–438
25.
KellyD H, 1984“Retinal inhomogeneity. I. Spatiotemporal contrast sensitivity”Journal of the Optical Society of America A1107–113
26.
KoenderinkJ JBoumanM Ade MesquitaA E BuenoSlappendelS, 1978“Perimetry of contrast detection thresholds of moving spatial sine-wave patterns: III. The target extent as a sensitivity controlling parameter”Journal of the Optical Society of America68854–860
27.
LandM F, 1995“The functions of eye movements in animals remote from man”, in Eye Movement Research Ed. FindlayJ M, (Amsterdam: Elsevier Science) pp 63–76
28.
LandM FEckertH, 1985“Maps of the acute zones of fly eyes”Journal of Comparative Physiology156525–538
29.
LeviD MKleinS A, 1990“Equivalent intrinsic blur in spatial vision”Vision Research301971–1993
MatherG, 1996“Image blur as a pictorial depth cue”Proceedings of the Royal Society of London, Series B263169–171
32.
MeineckeCKehrerI, 1994“Peripheral and foveal segmentation of angle texture”Perception & Psychophysics56326–334
33.
MoraB NCarmanG JAllmanJ M, 1989“In vivo functional localization of the human visual cortex using positron emission tomography and magnetic resonance imaging”Trends in Neuroscience12282–286
34.
MountcastleV, 1984“Central nervous mechanisms in mechanoreceptive sensibility”, in Handbook of Physiology Ed. Darian-SmithI: Section 1: The Nervous SystemVolume III. Sensory Processes Part 2 (Bethesda, MD: American Physiological Society) pp 789–878
35.
MyersonJManisP BMiezinF MAllmanJ M, 1977“Magnification in striate cortex and retinal ganglion cell layer of owl monkey: A quantitative comparison”Science198855–857
36.
PointerJ S, 1986“Visual representation at the cerebral cortex: Qualitative and quantitative aspects”Ophthalmic & Physiological Optics6171–175
37.
RaninenARovamoJ, 1986“Perimetry of critical flicker frequency in human rod and cone vision”Vision Research261249–1255
38.
Ransom-HoggASpillmannL, 1980“Perceptive field size in fovea and periphery of the light- and dark-adapted retina”Vision Research20221–228
39.
RovamoJMäkeläPWhitakerD, 1993“Models of the visual cortex on the basis of psychophysical observations”, in Functional Organisation of the Human Visual Cortex Eds GulyasBOttosonDRolandP E, (Oxford: Pergamon Press)
40.
RovamoJRaninenA, 1984“Critical flicker frequency and M-scaling of stimulus size and retinal illuminance”Vision Research241127–1131
41.
RovamoJRaninenA, 1990“Cortical acuity and the luminous flux collected by retinal ganglion cells at various eccentricities in human rod and cone vision”Vision Research3011–21
42.
RovamoJVirsuV, 1979“An estimation and application of the human cortical magnification factor”Experimental Brain Research37495–510
43.
RovamoJVirsuVNäsänenR, 1978“Cortical magnification factor predicts the photopic sensitivity of peripheral vision”Nature (London)27154–56
44.
SaarinenJ, 1987“Perception of positional relationships between line segments in eccentric vision”Perception16583–591
45.
SaarinenJ, 1988“Detection of mirror symmetry in random-dot patterns at different eccentricities”Vision Research28755–759
46.
SaarinenJRovamoJVirsuV, 1987“Texture discrimination at different eccentricities”Journal of the Optical Society of America A41699–1703
47.
ScheinS J, 1988“Anatomy of macaque fovea and spatial densities of neurons in foveal representations”Journal of Comparative Neurology269479–505
48.
ScheinS JDe MonasterioF M, 1987“Mapping of retinal and geniculate neurons onto striate cortex of macaque”Journal of Neuroscience7996–1009
49.
SchwartzE L, 1980“Computational anatomy and functional architecture of striate cortex: A spatial mapping approach to perceptual coding”Vision Research20645–669
50.
SchwartzE L, 1984“Spatial mapping and spatial vision in primate striate and infero-temporal cortex”, in Sensory Experience, Adaptation, and Perception Eds SpillmannLWootenB R, (Hillsdale, NJ: Lawrence Erlbaum Associates) pp 73–104
51.
SchwartzE L, 1994“Computational studies of the spatial architecture of primate visual cortex”, in Cerebral Cortex volume 10 Primary Visual Cortex in Primates Eds PetersARocklandK S, (New York: Plenum Press) pp 359–411
52.
SerenoM IDaleA MReppasJ BKwongK K, 1995“Borders of multiple visual areas in humans revealed by functional magnetic resonance imaging”Science268889–893
53.
TeuberH LBattersbyN SBenderM F, 1960Visual Field Defects after Penetrating Missile Wounds of the Brain (Cambridge, MA: Harvard University Press)
54.
TootellR B HSilvermanM SSwitkesEDe ValoisR L, 1982“Deoxyglucose analysis of retinotopic organization in primate striate cortex”Science218902–904
55.
TootellR B HSwitkesESilvermanM SHamiltonS L, 1988“Functional anatomy of macaque striate cortex. II. Retinotopic organization”Journal of Neuroscience81531–1568
56.
Van EssenD CNewsomeW TMaunsellJ H R, 1984“The visual field representation in striate cortex of the macaque monkey: Asymmetries, anisotropies, and individual variability”Vision Research24429–448
57.
VirsuVRovamoJ, 1979“Visual resolution, contrast sensitivity and the cortical magnification factor”Experimental Brain Research37475–494
58.
VirsuVRovamoJLaurinenPNäsänenR, 1982“Temporal contrast sensitivity and cortical magnification”Vision Research221211–1217
59.
WässleHGrunertURohrenbeckJBoycottB B, 1989“Cortical magnification factor and the ganglion cell density in the primate retina”Nature (London)341643–646
60.
WatsonA B, 1983“Detection and recognition of simple spatial forms”, in Physical and Biological Processing of Images Eds BraddickO JSleighA C, (New York: Springer)
61.
WattR JMorganM J, 1983“The recognition and representation of edge blur: Evidence for spatial primitives in human vision”Vision Research231465–1477
62.
WertheimT, 1980“Peripheral visual acuity”American Journal of Optometry57915–934
63.
WestheimerG, 1967“Spatial interaction in human cone vision”Journal of Physiology (London)190139–154
64.
WestheimerG, 1991“Sharpness discrimination for foveal targets”Journal of the Optical Society of America A8681–685
65.
WeymouthF, 1958“Visual sensory units and the minimal angle of resolution”American Journal of Ophthalmology46102–113
66.
WilsonH RLeviDMaffeiLRovamoJDe ValoisR, 1990“The perception of form: Retina to striate cortex”, in Visual Perception, the Neurophysiological Foundations Eds SpillmannLWernerJ S, (San Diego, CA: Academic Press) pp 231–272
67.
WrightM JJohnstonA, 1985“Invariant tuning of motion aftereffect”Vision Research251947–1955
