Receptive fields and functional architecture in two nonstriate visual areas (18 and 19) of the cat.
TL;DR: To UNDERSTAND VISION in physiological terms represents a formidable problem for the biologist, and one approach is to stimulate the retina with patterns of light while recording from single cells or fibers at various points along the visual pathway.
Abstract: To UNDERSTAND VISION in physiological terms represents a formidable problem for the biologist. I t am0 unts to learning how the nervous system handles incoming messages so that form, color, movement, and depth can be perceived and interpreted. One approach, perhaps the most direct, is to stimulate the retina with patterns of light while recording from single cells or fibers at various points along the visual pa thway. For each cell the optimum stimulus can be determined, and one can note the charac teristics common to cells at the next. each level in the visual pathway, and compare a given level with
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TL;DR: A summary of the layout of cortical areas associated with vision and with other modalities, a computerized database for storing and representing large amounts of information on connectivity patterns, and the application of these data to the analysis of hierarchical organization of the cerebral cortex are reported on.
Abstract: In recent years, many new cortical areas have been identified in the macaque monkey. The number of identified connections between areas has increased even more dramatically. We report here on (1) a summary of the layout of cortical areas associated with vision and with other modalities, (2) a computerized database for storing and representing large amounts of information on connectivity patterns, and (3) the application of these data to the analysis of hierarchical organization of the cerebral cortex. Our analysis concentrates on the visual system, which includes 25 neocortical areas that are predominantly or exclusively visual in function, plus an additional 7 areas that we regard as visual-association areas on the basis of their extensive visual inputs. A total of 305 connections among these 32 visual and visual-association areas have been reported. This represents 31% of the possible number of pathways if each area were connected with all others. The actual degree of connectivity is likely to be closer to 40%. The great majority of pathways involve reciprocal connections between areas. There are also extensive connections with cortical areas outside the visual system proper, including the somatosensory cortex, as well as neocortical, transitional, and archicortical regions in the temporal and frontal lobes. In the somatosensory/motor system, there are 62 identified pathways linking 13 cortical areas, suggesting an overall connectivity of about 40%. Based on the laminar patterns of connections between areas, we propose a hierarchy of visual areas and of somatosensory/motor areas that is more comprehensive than those suggested in other recent studies. The current version of the visual hierarchy includes 10 levels of cortical processing. Altogether, it contains 14 levels if one includes the retina and lateral geniculate nucleus at the bottom as well as the entorhinal cortex and hippocampus at the top. Within this hierarchy, there are multiple, intertwined processing streams, which, at a low level, are related to the compartmental organization of areas V1 and V2 and, at a high level, are related to the distinction between processing centers in the temporal and parietal lobes. However, there are some pathways and relationships (about 10% of the total) whose descriptions do not fit cleanly into this hierarchical scheme for one reason or another. In most instances, though, it is unclear whether these represent genuine exceptions to a strict hierarchy rather than inaccuracies or uncertainities in the reported assignment.
7,796 citations
TL;DR: The striate cortex was studied in lightly anaesthetized macaque and spider monkeys by recording extracellularly from single units and stimulating the retinas with spots or patterns of light, with response properties very similar to those previously described in the cat.
Abstract: 1. The striate cortex was studied in lightly anaesthetized macaque and spider monkeys by recording extracellularly from single units and stimulating the retinas with spots or patterns of light. Most cells can be categorized as simple, complex, or hypercomplex, with response properties very similar to those previously described in the cat. On the average, however, receptive fields are smaller, and there is a greater sensitivity to changes in stimulus orientation. A small proportion of the cells are colour coded.
2. Evidence is presented for at least two independent systems of columns extending vertically from surface to white matter. Columns of the first type contain cells with common receptive-field orientations. They are similar to the orientation columns described in the cat, but are probably smaller in cross-sectional area. In the second system cells are aggregated into columns according to eye preference. The ocular dominance columns are larger than the orientation columns, and the two sets of boundaries seem to be independent.
3. There is a tendency for cells to be grouped according to symmetry of responses to movement; in some regions the cells respond equally well to the two opposite directions of movement of a line, but other regions contain a mixture of cells favouring one direction and cells favouring the other.
4. A horizontal organization corresponding to the cortical layering can also be discerned. The upper layers (II and the upper two-thirds of III) contain complex and hypercomplex cells, but simple cells are virtually absent. The cells are mostly binocularly driven. Simple cells are found deep in layer III, and in IV A and IV B. In layer IV B they form a large proportion of the population, whereas complex cells are rare. In layers IV A and IV B one finds units lacking orientation specificity; it is not clear whether these are cell bodies or axons of geniculate cells. In layer IV most cells are driven by one eye only; this layer consists of a mosaic with cells of some regions responding to one eye only, those of other regions responding to the other eye. Layers V and VI contain mostly complex and hypercomplex cells, binocularly driven.
5. The cortex is seen as a system organized vertically and horizontally in entirely different ways. In the vertical system (in which cells lying along a vertical line in the cortex have common features) stimulus dimensions such as retinal position, line orientation, ocular dominance, and perhaps directionality of movement, are mapped in sets of superimposed but independent mosaics. The horizontal system segregates cells in layers by hierarchical orders, the lowest orders (simple cells monocularly driven) located in and near layer IV, the higher orders in the upper and lower layers.
6,388 citations
TL;DR: A neural network model for a mechanism of visual pattern recognition that is self-organized by “learning without a teacher”, and acquires an ability to recognize stimulus patterns based on the geometrical similarity of their shapes without affected by their positions.
Abstract: A neural network model for a mechanism of visual pattern recognition is proposed in this paper. The network is self-organized by “learning without a teacher”, and acquires an ability to recognize stimulus patterns based on the geometrical similarity (Gestalt) of their shapes without affected by their positions. This network is given a nickname “neocognitron”. After completion of self-organization, the network has a structure similar to the hierarchy model of the visual nervous system proposed by Hubel and Wiesel. The network consits of an input layer (photoreceptor array) followed by a cascade connection of a number of modular structures, each of which is composed of two layers of cells connected in a cascade. The first layer of each module consists of “S-cells”, which show characteristics similar to simple cells or lower order hypercomplex cells, and the second layer consists of “C-cells” similar to complex cells or higher order hypercomplex cells. The afferent synapses to each S-cell have plasticity and are modifiable. The network has an ability of unsupervised learning: We do not need any “teacher” during the process of self-organization, and it is only needed to present a set of stimulus patterns repeatedly to the input layer of the network. The network has been simulated on a digital computer. After repetitive presentation of a set of stimulus patterns, each stimulus pattern has become to elicit an output only from one of the C-cell of the last layer, and conversely, this C-cell has become selectively responsive only to that stimulus pattern. That is, none of the C-cells of the last layer responds to more than one stimulus pattern. The response of the C-cells of the last layer is not affected by the pattern's position at all. Neither is it affected by a small change in shape nor in size of the stimulus pattern.
4,713 citations
Cites methods from "Receptive fields and functional arc..."
...After completion of self-organization, the network acquires a structure similar to the hierarchy model of the visual nervous system proposed by Hubel and Wiesel (1962, 1965)....
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Book•
01 Jan 1966
TL;DR: Among the authors' patients was a bookkeeper with a severe form of sensory aphasia who could still draw up the annual balance sheet in spite of severe disturbances of speech and although he was unable to remember the names of his subordinates and used to refer to them incorrectly.
4,387 citations
TL;DR: Results suggest that rather than being exclusively feedforward phenomena, nonclassical surround effects in the visual cortex may also result from cortico-cortical feedback as a consequence of the visual system using an efficient hierarchical strategy for encoding natural images.
Abstract: We describe a model of visual processing in which feedback connections from a higher- to a lower- order visual cortical area carry predictions of lower-level neural activities, whereas the feedforward connections carry the residual errors between the predictions and the actual lower-level activities. When exposed to natural images, a hierarchical network of model neurons implementing such a model developed simple-cell-like receptive fields. A subset of neurons responsible for carrying the residual errors showed endstopping and other extra-classical receptive-field effects. These results suggest that rather than being exclusively feedforward phenomena, nonclassical surround effects in the visual cortex may also result from cortico-cortical feedback as a consequence of the visual system using an efficient hierarchical strategy for encoding natural images.
4,149 citations
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TL;DR: The present investigation, made in acute preparations, includes a study of receptive fields of cells in the cat's striate cortex, which resembled retinal ganglion-cell receptive fields, but the shape and arrangement of excitatory and inhibitory areas differed strikingly from the concentric pattern found in retinalganglion cells.
Abstract: In the central nervous system the visual pathway from retina to striate cortex provides an opportunity to observe and compare single unit responses at several distinct levels. Patterns of light stimuli most effective in influencing units at one level may no longer be the most effective at the next. From differences in responses at successive stages in the pathway one may hope to gain some understanding of the part each stage plays in visual perception. By shining small spots of light on the light-adapted cat retina Kuffler (1953) showed that ganglion cells have concentric receptive fields, with an 'on' centre and an 'off ' periphery, or vice versa. The 'on' and 'off' areas within a receptive field were found to be mutually antagonistic, and a spot restricted to the centre of the field was more effective than one covering the whole receptive field (Barlow, FitzHugh & Kuffler, 1957). In the freely moving lightadapted cat it was found that the great majority of cortical cells studied gave little or no response to light stimuli covering most of the animal's visual field, whereas small spots shone in a restricted retinal region often evoked brisk responses (Hubel, 1959). A moving spot of light often produced stronger responses than a stationary one, and sometimes a moving spot gave more activation for one direction than for the opposite. The present investigation, made in acute preparations, includes a study of receptive fields of cells in the cat's striate cortex. Receptive fields of the cells considered in this paper were divided into separate excitatory and inhibitory ('on' and 'off') areas. In this respect they resembled retinal ganglion-cell receptive fields. However, the shape and arrangement of excitatory and inhibitory areas differed strikingly from the concentric pattern found in retinal ganglion cells. An attempt was made to correlate responses to moving stimuli
4,405 citations
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.
Abstract: THE DISCHARGES carried in the optic nerve fibers contain all the information which the central nervous system receives from the retina. A correct interpretation of discharge patterns therefore constitutes an important step in the analysis of visual events. Further, investigations of nervous activity arising in the eye reveal many aspects of the functional organization of the neural elements within the retina itself. Following studies of discharges in the optic nerve of the eel’s eye by Adrian and Matthews (2,3), Hartline and his colleagues described the discharge pattern in the eye of the Limulus in a series of important and lucid papers (for a summary see 20). In the Limulus the relationship between the stimulus to the primary receptor cell and the nerve discharges proved relatively simple, apparently because the connection between sense cell and nerve fiber was a direct one. Thus, when stimulation is confined to one receptor the discharge in a single Limulus nerve fiber will provide a good indication of excitatory events which take place as a result of photochemical processes. Discharges last for the duration of illumination and their frequency is a measure of stimulus strength. Lately, however, it was shown by Hartline et al. (22) that inhibitory interactions may be revealed when several receptors are excited. On the whole, the Limulus preparation shows many features which are similar to other simple sense organs, for instance, stretch receptors. In the latter, however, instead of photochemical events, stretch-deformation acts as the adequate stimulus on sensory terminals and is translated into a characteristic discharge pattern. The discharge from the cold-blooded vertebrate retina (mainly frogs) proved much more complex. Hartline found three main types when recording from single optic nerve fibers: (i) “on” discharges, similar to those in the Limulus, firing for the duration of the light stimulus, (ii) “off” discharges appearing when a light stimulus was withdrawn, and (iii) ‘con-off” discharges, a combination of the former two, with activity confined mainly to onset and cessation of illumination. The mammalian discharge patterns were studied in a number of species by Granit and his co-workers in the course of their extensive work on the physiology of the visual system (summaries in 13, 15). On the whole, they did not observe any fundamental differences between frog and mammalian discharge types (see later).
2,540 citations
2,495 citations
TL;DR: Observations upon the modality and topographical attributes of single neurons of the first somatic sensory area of the cat’s cerebral cortex, the analogue of the cortex of the postcentral gyrus in the primate brain, support an hypothesis of the functional organization of this cortical area.
Abstract: THE PRESENT PAPER describes some observations upon the modality and topographical attributes of single neurons of the first somatic sensory area of the cat’s cerebral cortex, the analogue of the cortex of the postcentral gyrus in the primate brain. These data, together with others upon the response latencies of the cells of different layers of the cortex to peripheral stimuli, support an hypothesis of the functional organization of this cortical area. This is that the neurons which lie in narrow vertical columns, or cylinders, extending from layer II through layer VI make up an elementary unit of organization, for they are activated by stimulation of the same single class of peripheral receptors, from almost identical peripheral receptive fields, at latencies ers. It is early These which are not significantly different for the cells of the various layemphasized that this pattern of organization obtains only for the repetitiv neurons ‘e responses may be rela of ted cortical in quite neurons different to brief peripheral stimuli. organization patterns when analyzed in terms of later discharges. A report of these experiments was made to the American Physiological Society in September, 1955 (10, 17).
2,230 citations
TL;DR: The purpose was to learn the age at which cortical cells have normal, adult-type receptive fields, and to find out whether such fields exist even in animals that have had no patterned visual stimulation.
Abstract: IN A SERIES OF STUDIES on the cat over the past 5 years we have recorded from single cells in the striate cortex and mapped receptive fields using patterned retinal stimulation. The results suggest that connections between geniculate and striate cortex, and between cortical cells, must be highly specific (5). Indeed, cells in the striate cortex respond in such a characteristic way that departures from the normal adult physiology should be easily recognizable. In the present study we have made similar experiments in kittens ranging in age from l-3 weeks. Our purpose was to learn the age at which cortical cells have normal, adult-type receptive fields, and to find out whether such fields exist even in animals that have had no patterned visual stimulation.
1,071 citations