Analysis of the elastic net model applied to the formation of ocular dominance and orientation columns

Goodhill, Geoffrey J.; Cimponeriu, Andrei

doi:10.1088/0954-898x/11/2/303

Cited by 32 publications

(54 citation statements)

References 44 publications

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“…Formation of a pool suited to a particular task concerns not just single neuron properties but how the properties of a given neuron are related to those of its neighbors. How different orderly maps are coregistered and what constraints each has on the other has been a topic of intense consideration by both biologists and computational modelers (Goodhill et al, 2002;Swindale, 2004).…”

Section: Specialization In Topography Of Representationmentioning

confidence: 99%

Disparity Channels in Early Vision

Roe¹,

Parker²,

Born

et al. 2007

J. Neurosci.

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The past decade has seen a dramatic increase in our knowledge of the neural basis of stereopsis. New cortical areas have been found to represent binocular disparities, new representations of disparity information (e.g., relative disparity signals) have been uncovered, the first topographic maps of disparity have been measured, and the first causal links between neural activity and depth perception have been established. Equally exciting is the finding that training and experience affects how signals are channeled through different brain areas, a flexibility that may be crucial for learning, plasticity, and recovery of function. The collective efforts of several laboratories have established stereo vision as one of the most productive model systems for elucidating the neural basis of perception. Much remains to be learned about how the disparity signals that are initially encoded in primary visual cortex are routed to and processed by extrastriate areas to mediate the diverse capacities of three-dimensional vision that enhance our daily experience of the world.

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Section: Specialization In Topography Of Representationmentioning

confidence: 99%

Disparity Channels in Early Vision

Roe¹,

Parker²,

Born

et al. 2007

J. Neurosci.

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“…Rather, the simulations presented here suggest that the degree of OD column segregation at the time of birth is a critical factor in determining the degree of angioscotoma representation and that the correlation with OD column width is partly a byproduct of this. In the elastic net, OD column periodicity and the time course of OD development are both controlled by the same parameter l, and the model predicts that columns that develop faster should be wider, whereas those that develop slower should be narrower (Hoffsümmer et al, 1995(Hoffsümmer et al, , 1996Goodhill and Cimponeriu, 2000). We therefore propose that natural variability in the degree of OD column segregation at birth in squirrel monkeys could be an important biological variable determining the degree of angioscotoma representation.…”

Section: Discussionmentioning

confidence: 99%

“…8) added orientation preference and selectivity dimensions. These dimensions were represented in polar coordinates by N OR ϭ 6 values of orientation preference arranged uniformly around a ring of radius r. The value of r relative to l dictates the timing of development of the OR map relative to the OD map (Hoffsüm-mer et al, 1995(Hoffsüm-mer et al, , 1996Goodhill and Cimponeriu, 2000). For this set of simulations, a two-dimensional cortical net of 180 ϫ 180 ϭ 32,400 points was mapped to the training set of 50 ϫ 50 ϫ 2 ϫ 6 ϭ 30,000 feature points.…”

Section: Methodsmentioning

confidence: 99%

“…2 A) and can be related to the correlation between the eyes (Yuille et al, 1996). Increasing l both accelerates OD column formation and makes columns broader (Goodhill and Willshaw, 1990;Hoffsümmer et al, 1995Hoffsümmer et al, , 1996Goodhill and Cimponeriu, 2000). The parameter K b is the value of the annealing parameter at the onset of visual experience; the smaller the K b value, the longer maps have been allowed to develop before visual experience, so the more segregated OD columns are at birth.…”

Section: Angioscotoma Representations In the One-dimensional Elastic Netmentioning

confidence: 99%

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The Effect of Angioscotomas on Map Structure in Primary Visual Cortex

Giacomantonio¹,

Goodhill²

2007

J. Neurosci.

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When blood vessels occlude the photoreceptor layer in the retina, they cast shadows onto the photoreceptors, creating angioscotomas (regions of the visual field to which that eye is blind). Remarkably, Adams and Horton (2002) have recently shown that it is sometimes possible to observe representations of these angioscotomas anatomically in the primary visual cortices of squirrel monkeys. However, there is substantial variability in the degree and form of these representations. The source of this variability is difficult to determine experimentally, because experimental studies are unavoidably limited by small sample size. In addition, experimental studies cannot compare the map structure that would develop with and without an angioscotoma. Here, we investigate these phenomena computationally using feature-mapping models of visual cortical development, which are not subject to the same limitations. These models suggest that the primary source of variability in angioscotoma representation is the precise timing of the onset of visual experience relative to the time course of ocular dominance column segregation. Furthermore, the models predict that angioscotomas could compete for control of local column layout with other influences such as cortical shape but that they have a small effect on the structure of orientation preference maps.

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“…Several models of self-organization have been proposed to explain how the orientation maps in the cortex could form (Bartsch and van Hemmen 2001;Burger and Lang 1999;Goodhill and Cimponeriu 2000;Kohonen 1981Kohonen , 1982Kohonen , 1995Miller 1994;Obermayer et al 1990;von der Malsburg 1973;see Swindale 1996 for a review). In most of these models, only the afferent connections self-organize while the lateral interactions are represented as a fixed, uniform interaction kernel.…”

Section: Introductionmentioning

confidence: 99%

Contour integration and segmentation with self-organized lateral connections

Choe

Miikkulainen

2004

Biological Cybernetics

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Contour integration in low-level vision is believed to occur based on lateral interaction between neurons with similar orientation tuning. How such interactions could arise in the brain has been an open question. Our model suggests that the interactions can be learned through input-driven self-organization, i.e. through the same mechanism that underlies many other developmental and functional phenomena in the visual cortex. The model also shows how synchronized firing mediated by these lateral connections can represent the percept of a contour, resulting in performance similar to that of human contour integration. The model further demonstrates that contour integration performance can differ in different parts of the visual field, depending on what kinds of input distributions they receive during development. The model thus grounds an important perceptual phenomenon onto detailed neural mechanisms, so that various structural and functional properties can be measured, and predictions can be made to guide future experiments.

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Analysis of the elastic net model applied to the formation of ocular dominance and orientation columns

Cited by 32 publications

References 44 publications

Disparity Channels in Early Vision

Disparity Channels in Early Vision

The Effect of Angioscotomas on Map Structure in Primary Visual Cortex

Contour integration and segmentation with self-organized lateral connections

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