Journal ArticleDOI
A model for the temporal organization of X- and Y-type receptive fields in the primate retina.
Jacob Richter,Shimon Ullman +1 more
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The X-and Y-type responses predicted by the model, for a variety of stimuli, were examined and compared with available electrophysiological recordings and certain predictions derived from the model are discussed.Abstract:
A model is proposed for the temporal characteristics of X- and Y-type responses of ganglion cells in the primate retina. The main suggestions of the model are: (I) The X-type temporal response is determined primarily by the delay between center and surround contributions. (II) The Y-type response is generated in the inner plexiform layer by a derivative-like operation on the bipolar cell's input, followed by a rectification in the convergence of these inputs onto the Y-ganglion-cell. (III) The derivative-like operation is obtained by recurrent inhibition in the dyad synaptic structure. The X- and Y-type responses predicted by the model, for a variety of stimuli, were examined and compared with available electrophysiological recordings. Finally, certain predictions derived from the model are discussed.read more
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An emergent model of orientation selectivity in cat visual cortical simple cells
TL;DR: A 1:4 scale model of a 1700 microns by 200 microms region of layer IV of cat primary visual cortex is presented to demonstrate that local intracortical excitation may provide the dominant source of orientation-selective input and provide a unified account of intracellular and extracellular inhibitory blockade experiments that had previously appeared to conflict over the role of inhibition.
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The Measurement of Visual Motion
Ellen C. Hildreth,Shimon Ullman +1 more
TL;DR: The analysis of visual motion plays a central role in biological systems as discussed by the authors, and sophisticated mechanisms for extracting and utilizing motion exist even in simple animals, such as frogs and houseflies, that respond selectively to small, dark objects moving in its visual field.
Journal ArticleDOI
Cable theory in neurons with active, linearized membranes.
TL;DR: This investigation aims at exploring some of the functional consequences of single neurons containing active, voltage dependent channels for information processing, and study the linearized behaviour of active channels giving rise to quasi-active membranes in extended neuronal structures.
Journal ArticleDOI
Dynamic connections in neural networks
TL;DR: The purpose of this paper is to extend the methodology to cover several aspects of change and memory in massively parallel networks.
Journal ArticleDOI
The detection of intensity changes by computer and biological vision systems
TL;DR: The implementation of a theory for the detection of intensity changes, proposed by Marr and Hildreth, where the image is first processed independently through a set of different size operators, whose shape is the Laplacian of a Gaussian, ▿2G(x, y).
References
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Journal ArticleDOI
Discharge patterns and functional organization of mammalian retina
TL;DR: The Limulus preparation shows many features which are similar to other simple sense organs, for instance, stretch receptors, however, instead of photochemical events, stretch-deformation acts as the adequate stimulus on sensory terminals and is translated into a characteristic discharge pattern.
Journal ArticleDOI
The contrast sensitivity of retinal ganglion cells of the cat.
TL;DR: Spatial summation within cat retinal receptive fields was studied by recording from optic‐tract fibres the responses of ganglion cells to grating patterns whose luminance perpendicular to the bars varied sinusoidally about the mean level.
Journal ArticleDOI
Organization of the retina of the mudpuppy, Necturus maculosus. II. Intracellular recording.
Frank S. Werblin,John E. Dowling +1 more
TL;DR: The intracellularly recorded response characteristics of each type of neuron in a vertebrate retina are described, and the response of each neuron to the responses of those neurons to which it is synaptically coupled are related.
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Electric Current Flow in Excitable Cells
TL;DR: In this article, the authors defined electric shock as a sudden violent response to electric current flow through any part of a person s body and electrocution is death caused by electric shock Primary electrical injury is tissue damage produced directly by electrical current or voltage Secondary injuries such as falls are common.