Showing papers on "Receptive field published in 1976"
TL;DR: The properties of single cells in striate cortex of the rhesus monkey, representing the visual field 2 degrees -5 degrees from the fovea, were examined quantitatively with stationary and moving stimuli and showed differences between S-type and CX-type cells.
Abstract: 1. The properties of single cells in striate cortex of the rhesus monkey, representing the visual field 2 degrees -5 degrees from the fovea, were examined quantitatively with stationary and moving ...
507 citations
TL;DR: The nature of the Y cell nonlinearity was found to be rectification, as determined from measurements of the second harmonic response as a function of contrast.
Abstract: 1. The mechanism which makes Y cells different from X cells was investigated. 2. Spatial frequency contrast sensitivity functions for the fundamental and second harmonic responses of Y cells to alternating phase gratings were determined. 3. The fundamental spatial frequency response was predicted by the Fourier transform of the sensitivity profile of the Y cell. The high spatial frequency cut-off of a Y cell's fundamental response was in this way related to the centre of the cell's receptive field. 4. The second harmonic response of a Y cell did not cut off at such a low spatial frequency as the fundamental response. This result indicated that the source of the second harmonic was a spatial subunit of the receptive field smaller in spatial extent than the centre. 5. Contrast sensitivity vs. spatial phase for a Y cell was measured under three conditions: a full grating, a grating seen through a centrally located window, a grating partially obscured by a visual shutter. The 2nd/1st harmonic sensitivity ratio went down with the window and up with the shutter. These results implied that the centre of Y cells was linear and also that the nonlinear subunits extended into the receptive field surround. 6. Spatial localization of the nonlinear subunits was determined by means of a spatial dipole stimulus. The nonlinear subunits overlapped the centre and surround of the receptive field and extended beyond both. 7. The nature of the Y cell nonlinearity was found to be rectification, as determined from measurements of the second harmonic response as a function of contrast. 8. Spatial models for the Y cell receptive field are proposed.
451 citations
TL;DR: A complex vector analysis of the proximal motion pattern is accomplished at the initial stage of physiological signal recording and that it is a consequence of receptive field organization is indicated in terms of vector calculus.
Abstract: Perceptual organization during short tachistoscopic presentation of stimulus patterns formed by ten moving bright spots, representing a human body in walking, running, etc. was investigated. Exposure times were .1 sec to .5 sec. The results reveal that in all Ss the dot pattern is perceptually organized to a “gestalt”, a walking, running, etc., person at an exposure time of .2 sec. 40% of Ss perceived a human body in such motion at presentation times as short as 0.1 sec. Under the experimental conditions used the track length of the bright spots at the threshold of integration to a moving unit was of the size order 10′ visual angle. This result is regarded as indicating that a complex vector analysis of the proximal motion pattern is accomplished at the initial stage of physiological signal recording and that it is a consequence of receptive field organization. It is discussed in terms of vector calculus.
384 citations
TL;DR: Results of these experiments indicate that the enhancement of visual response seems likely to be related specifically to eye movements both on physiological and behavioral grounds, and the response-free term "attention" is probably inappropriate for the phenomenon.
Abstract: 1. Cells in the superficial layers of monkey superior colliculus respond more vigorously to a spot of light falling in their receptive fields when the monkey uses that spot of light as the target f...
378 citations
TL;DR: Around the classical receptive field (regions within which a moving or flashing bar can elicit a response from a cell) there are large regions which dramatically influence the cell's responsiveness, which are facilitatory and inhibitory regions of the receptive field.
363 citations
TL;DR: In adult mice of the C57BL/6J strain the projection of the visual field was systematically mapped under direct vision, and whiskers were featured much more prominently in the tectum, and structures close to the eye, such as the pinna and cheek, receive more representation than the tail or hindpaws.
Abstract: In adult mice of the C57BL/6J strain the projection of the visual field was systematically mapped under direct vision. As in other vertebrate species the nasal (anterior) field projected anterolaterally, and the inferior field posterolaterally. Values of magnification-1 (m-1, or degrees of visual field per millimeter tectal surface) were calculated over most of the tectum, for measurements in the coronal and sagittal planes. Whereas m-1 was fairly constant for measurement pairs in sagittal planes, for coronal planes there was a rather large, elongated, horizontally oriented area in the upper field of vision within which m-1 was smaller than elsewhere. In this area m-1 was anisotropic, with a ratio of almost 2:1 between sagittal and coronal planes. In a previously study we had observed that many cells recorded in deeper tectal layers responded to somatosensory stimulation, with whiskers especially conspicuous. In a given penetration perpendicular to the tectal surface, somatosensory receptive fields recorded in the deeper tectum were always concerned with that group of whiskers or with those parts of the body that crossed the regions of visual field represented in the superficial layers directly above. Given this information on the visual coordinates associated with certain somatosensory fields, the detailed mapping of the visual field onto the tectum made it possible to prepare a map of the somatosensory projection on the tectum. The resulting representation differed markedly from maps described for the classic somatosensory pathway. In the tectum the somatosensory map was dictated by the visual-field projection rather than by the peripheral tactile innervation density. Whiskers were thus featured much more prominently in the tectum, and structures close to the eye, such as the pinna and cheek, receive more representation than the tail or hindpaws.
353 citations
TL;DR: The different characteristics of the enhancement instriate cortex and the observation of enhancement in the colliculus following ablation of striate cortex suggest that this cortical area is an unlikely source of the collicular enhancement.
Abstract: 1. We have studied the visual enhancement effect in two areas of the cerebral cortex of monkeys. The response of the cells to a visual stimulus was determined both when the monkey used the visual stimulus as the target for a saccadic eye movement and when he did not. 2. In striate cortex cells with nonoriented, simple, complex, and hypercomplex receptive-field types were studied. Clear enhancement of the response to the appropriate visual stimulus was seldom seen when the monkey used the stimulus as a target for a saccade. In addition, any enhancement effect seen was nonselective; it occurred whether the monkey made a saccade to the receptive-field stimulus or some other stimulus at a point distant from the receptive field. The enhancement also occurred whether the monkey made a saccade to the stimulus or just released the bar when the stimulus dimmed. 3. This nonselective enhancement in striate cortex is in striking contrast to the selective enhancement of the visual response seen in the superior colliculus. The different characteristics of the enhancement in striate cortex and the observation of enhancement in the colliculus following ablation of striate cortex suggest that this cortical area is an unlikely source of the collicular enhancement. 4. These observations reinforce the distinction between striate cortex and superior colliculus. Striate cortex is an excellent analyzer of stimulus characteristics but a poor evaluator of stimulus significance. The superior colliculus is an excellent evaluator but a poor analyzer. 5. The area of frontal eye fields in which cells have clear visual responses has been better localized. Enhancement of the visual response of these cells also occurs and, at least for some cells, the response enhancement is selective. The response enhancement, like the visual properties of these frontal eye field cells, appears to be more closely related to the properties of superior colliculus cells than to striate cortex cells.
317 citations
TL;DR: The responses of on-center and directionally selective cells to ACh, to anticholinesterase, and to cholinergic antagonists in control medium indicate that the retina contains one or more synapses using ACh as a neurotransmitter.
Abstract: 1. Rabbit retinas were isolated and superfused with a physiological medium. Ganglion cell activity was recorded during stimulation with focused light, and receptive fields were mapped. Receptive fields were identical to those found in vivo and did not change during a 6-h incubation. After the receptive field of a ganglion cell had been identified, acetylcholine or related agents were introduced singly or in combination into the medium, and their effect on the cell's spontaneous and light-evoked activity was observed. 2. Ganglion cells with on-center or directionally selective receptive fields were excited when ACh was added to the medium. The response to exogenous ACh was prevented by cholinergic antagonists. 3. These cells' spontaneous activity and response to light were enhanced by anticholinesterase and depressed by cholinergic antagonists. Antagonists varied in their ability to block the light-evoked response, with dihydro-beta-erythroidine the most effective. 4. Thresholds for ACh or the related agents were low, ranging from 1 to 40 muM; their effects were rapidly and completely reversed when the retina was returned to control medium. 5. In retinas incubated in medium containing 20 mM Mg2+ and 0.2 mM Ca2+, ganglion cells lost completely both their spontaneous and light-evoked activity, but retained their ability to generate action potentials in response to elevated K+. Ganglion cell activity rapidly returned to normal when the retina was returned to medium containing normal electrolytes. On-center and directionally selective cells were excited by ACh in retinas where synaptic transmission had been inhibited by 20 mM Mg2+ and 0.2 mM Ca2+. 6. The responses of on-center and directionally selective cells to ACh, to anticholinesterase, and to cholinergic antagonists in control medium indicate that the retina contains one or more synapses using ACh as a neurotransmitter. The response to ACh in retinas exposed to 20 mM Mg2+ and 0.2 mM Ca2+ suggests that at least one such synapse in on the ganglion cell itself. 7. Off-center cells were inhomogenous in their response to ACh. Although some responded just as the other classes of cell, the majority responded quite weakly and a subgroup was encountered which was entirely unaffected by even 1 mM ACh, by levels of physostigmine which inactivate virtually all retinal acetyl-cholinesterase, or by high concentrations of cholinergic antagonists. Only 2 of 20 off-cells tested in the presence of 20 mM Mg2+ and 0.2 mM Ca2+ were excited by ACh. Apparently ACh is not a primary transmitter for most off-cells.
250 citations
TL;DR: There is general correspondence between the maps of visual space, auditory space and the body surface in the superior colliculus of the golden hamster, which may be important in the regulation of orienting behaviour towards novel peripheral stimuli.
Abstract: The superior colliculus of the golden hamster was investigated by means of multi-unit and single unit recording. The retinotopic map, which probably embraces a projection from the entire retina of the contralateral eye, is organized as in other vertebrates, with the central field represented in the anterior colliculus, the upper field medially. Magnification factor is fairly uniform and is about 0.02 mm/deg. There is a small binocular segment (where almost half of all neurones have input from the ipsilateral eye) in the anterior colliculus, representing the area of field around the area centralis and the anterior pole of the field. In the more superficial layers, units have small (about 10 deg diameter) receptive fields, which can be classified as symmetrical, responding to slow movement (80%), very fast movement detectors (6%), directional movement detectors (13%) and axial movement detectors (1%). In the deeper layers, below the stratum opticum, receptive field size increases dramatically and many cells habituate rapidly, making them sensitive only to new events. Receptive fields can be classified as movement detectors (89%), directional movement detectors (10%) and axial movement detectors (2%). All directional receptive fields, at least in the upper visual field, have an upward component in their directional preferences. About 42% of deeper layer cells have somatic sensory input, responding to light touch on the fur or whiskers of the contralateral half of the body. Some 5% of cells respond to complex sounds on the contralateral side of the animal. Many of these somatic and auditory cells also have visual receptive fields and, throughout the colliculus, there is general correspondence between the maps of visual space, auditory space and the body surface. This correlation may be important in the regulation of orienting behaviour towards novel peripheral stimuli.
230 citations
TL;DR: It was concluded that following partial de Afferentation, the remaining afferents can establish connection with deafferented cells but the data presented did not allow a conclusion as to whether the new connections were produced by sprouting or by the unmasking of existing connections.
226 citations
TL;DR: The spatial frequency of the sine-wave grating eliciting the optimal response could not be predicted from the organization of the receptive field of each cell as determined by stationary or moving stimuli.
Abstract: 1. The response properties of single cells in monkey striate cortex were examined using moving bars, square-wave gratings, and sine-wave gratings. 2. The moving of cells studied were not selective for bar width or for the spatial frequency of square-wave gratings. 3. Most cells responded selectively to the spatial frequency of the sine-wave gratings. 4. The spatial frequency of the sine-wave grating eliciting the optimal response could not be predicted from the organization of the receptive field of each cell as determined by stationary or moving stimuli. 5. The sharpness of spatial-frequency selectivity is only slightly more pronounced in S-type cells than in CX-type cells. 6. S-type and CX-type cells differ significantly in the temporal modulation of their discharges to gratings. S-type cells discharge in sharp bursts to each cycle which traverses the receptive field. CX-type cells discharge in a rather continuous fashion. This measure can be used reliably to classify cells as S or CS type.
01 Jan 1976
TL;DR: The ironic poem of Heinrich Heine would be incorrect as a neuronal machine leaves little possibility for frogs to “erquicken… an Sonnenblicken” as the angular velocity of the sun and the shadows cast by stationary objects in the frog’s habitat would be too slow to be discovered by the movement-detecting neuronal systems.
Abstract: Due to recent behavioral and electrophysiological data found in different anurans, some investigators believe that the visual system of frogs and toads is a highly specialized machinery which detects only self-moving visual signals relevant to the survival of the animals (p. 357 f., 435 ff.). Other visual signals are believed to be “suppressed” by the neuronal network of the visual system. Thus the ironic poem of Heinrich Heine would be incorrect as such a neuronal machine leaves little possibility for frogs to “erquicken… an Sonnenblicken”. The angular velocity of the sun and the shadows cast by stationary objects in the frog’s habitat would be too slow to be discovered by the movement-detecting neuronal systems.
TL;DR: The visual cortex of the golden hamster was studied by means of multi‐unit and single unit recording, which revealed three separate retinotopic maps of the visual field in the posterior cortex, which resemble simple, complex and hypercomplex cells in the cat cortex.
Abstract: The visual cortex of the golden hamster was studied by means of multi-unit and single unit recording, which revealed three separate retinotopic maps of the visual field in the posterior cortex. V1, corresponding to cyto-architectonic area 17, has the contralateral temporal field represented medially, the central visual field (extending about 10 deg ipsilateral) represented laterally and the lower field anteriorly. The borders of the map, especially for the upper field, seem to be more restricted than the whole visual field available to the contralateral hemiretina: V1 probably does not represent the extreme periphery of the field. A large fraction of V1 has binocular input, for up to about 50 deg lateral to the vertical midline. There is a retinotopic reversal near the representation of the vertical midline where V1 meets V2 (corresponding to the more lateral "area 18a"). There is another retinotopic reversal at the extremity of the contralateral field representation, where V1 meets Vm (the medial visual area, corresponding to "area 18"). V2 and Vm each contain a reduced mirror image version of the map in V1. Almost all isolated single units in V1 have receptive fields that can be classified as radially symmetrical (60%) or asymmetrical (35%). Symmetrical fields have ON (13%), OFF (4%), ON-OFF (30%) or "SILENT" (12%) central areas when plotted with flashing spots. There are minor but not striking differences between these groups in their field sizes, velocity preferences and so on. They almost invariably prefer moving to stationary stimuli but are not selective for orientation or direction of movement. Asymmetrical fields are of four types, three of which (type 1, 11%; type 2, 17%; and type 3, 2%) are orientation selective and resemble simple, complex and hypercomplex cells in the cat cortex. Some of these have direction as well as orientation preference. Axial movement detectors (5%) have a selectivity for one axis of motion, and thus prefer one orientation of edge, but respond equally well to movement of a spot. Vertical and horizontal orientation preferences, especially the latter, are much the most common. There is some evidence of clustering of cells according to receptive field type and, possibly, preferred orientation. Asymmetrical cells are, relatively somewhat rarer in the deeper cortical layers. Within the binocular segment, fully 89% of cells are binocularly driven and the receptive fields are similar in the two eyes. Receptive fields tend to increase in size away from the area centralis representation and, in a complementary fashion, the magnification factor decreases from up to 0.1 mm/deg at the area centralis representation to about 0.02 mm/deg for the peripheral field.
TL;DR: It is suggested that the sensitive period for cortical binocular development consists of two phases, in which an increasing number of cortical neurones becomes fixed in their properties, while those that remain modifiable are as modifiable as they were at the end of the first phase.
Abstract: 1. Twenty-three kittens were monocularly deprived of vision until the age of 4, 5, 6 or 7 weeks. Their deprived eyes were then opened, and their experienced eyes shut for a further 3-63 days. After this time physiological recordings were made in the visual cortex, area 17. Three control kittens, monocularly deprived for various periods, showed that at the time of reverse-suturing, few neurones could be influenced at all from the deprived eye. 2. Following reverse-suturing, the initially deprived eye regained control of cortical neurones. This switch of cortical ocular dominance was most rapid following reverse-suturing at the age of 4 weeks. Delaying the age of reverse-suturing reduced the rate and then the extent of the cortical ocular dominance changes. 3. The cortex of reverse-sutured kittens is divided into regions of cells dominated by one eye or the other. The relative sizes of these ocular dominance columns changed during reversed deprivation. The columns devoted to the initially deprived eye were very small in animals reverse-sutured for brief periods, but in animals that underwent longer periods of reversed deprivation, the columns driven by that eye were larger, while those devoted to the initially open eye were smaller. 4. Clear progressions of orientation columns across the cortex were apparent in many of the kittens, but, in contrast to the situation in normal or strabismic kittens, these sequences were disrupted at the borders of eye dominance columns: the cortical representations of orientation and ocular dominance were not independent. 5. Binocular units in these kittens were rather rare, but those that could be found often had dissimilar receptive field properties in the two eyes. Commonly, a cell would have a normal orientation selective receptive field in one eye, and an immature, unselective receptive field in the other. Cells that had orientation selective receptive fields in both eyes often had greatly differing orientation preferences in the two eyes, occasionally by nearly 90 degrees. 6. During the reversal of deprivation effects, the proportion of receptive fields exhibiting mature properties declined in the initially experienced eye, while the proportion increased in the initially deprived eye. Similarly, the average band width of orientation tuning of receptive fields in the initially deprived eye decreased, while that of receptive fields in the initially experienced eye increased. 7. One kitten was reverse-sutured twice, to demonstrate that cortical ocular dominance may be reversed a second time, even after one reversal of ocular dominance. 8. It is suggested that the sensitive period for cortical binocular development consists of two phases. In the first phase, all cortical neurones may be modified by experience, but the rate at which they may be modified decreases with age. In the second phase, an increasing number of cortical neurones becomes fixed in their properties, while those that remain modifiable are as modifiable as they were at the end of the first phase. 9...
TL;DR: The properties of the pontine visual cells suggest a corticopontocerebellar pathway sensitive to a wide range of speeds and directions of movement, but not sensitive to precise form.
Abstract: Two hundred and thirty-two visually activated neurones were recorded in a small area of the rostral pontine nuclei of cats. The location of visually activated neurones was coextensive with the input from visual areas of cat's cortex as determined by degeneration studies. 2. Pontine visual cells could only be driven by visual stimuli. Cells responsive to somatosensory or auditory stimuli were also found in different regions in rostral pontine nuclei. They too responded to only one modality. 3. 96% of the cells were directionally selective. 4. Pontine visual cells were responsive to a wide range of stimulus speeds. Some cells responded to targets moving as fast as 1000 degrees/sec without losing directional selectivity. No pontine visual cells gave a clearly sustained response to a stationary stimulus. 5. Exact stimulus configurations were not critical. Large fields containing many spots were the most effective stimuli for 50% of the cells. Inhibition of responses depending upon stimulus dimensions, direction of movement, or location in the visual field was found for many cells. 6. Receptive field dimensions were large, ranging in size from 3 degrees X 4 degrees to more than an entire hemifield. 7. 94% of the cells had receptive fields which were centred in the contralateral hemifield. 8. 98% of the cells could be driven from both eyes. 9. The properties of the pontine visual cells suggest a corticopontocerebellar pathway sensitive to a wide range of speeds and directions of movement, but not sensitive to precise form.
TL;DR: These cells in the superior colliculus receive an extraretinal input which permits them to differentiate betweent real stimulus movements and stimulus movements resulting from the monkey's own eye movements.
Abstract: 1. In order to see whether cells in the superficial layers of the monkey superior colliculus can differentiate between real stimulus movement and self-induced stimulus movement we compared the discharge of these cells to stimulus movement in front of the stationary eye with stimulus movement generated by eye movements across a stationary stimulus. 2. Most of the cells recorded (65% of 231 cells) responded to stimulus velocities in front of the stationary eye as fast as those occurring during the peak velocity of a saccadic eye movement. Those cells that do respond usually have weak inhibitory regions and tend to have receptive fields further from fovea. 3. Move (61% of 105 cells) of the cells that did respond to rapid stimulus movement did not respond when an eye movement swept the receptive field over a stationary stimulus. 4. About half of these cells differentiated between these stimulus conditions when we used stimuli at least 1 log unit above background illumination; the remaining cells differentiated for stimuli 2 and 3 log units above background. Many cells differentiated between the two stimulus conditions over a wide range of directions of movement and the effect appears with about equal frequency in receptive fields at all distances from the fovea. 5. The differentiation is present for most cells even when the background illumination is reduced, indicating that visual factors are not the cause of the effect on these cells but may modify the response of other cells. 6. The suppression of background activity accompanying eye movements in the light is present following eye movements made in total darkness; the suppression, therefore, must result from an extraretinal signal. 4. The failure of these cells to respond to visual stimulation during eye movements is due to the same extraretinal signal that produces the suppression since a) the cells that show this suppression tend to be those that fail to respond to stimuli during eye movements, b) the time course of the suppression matches the time at which the effects of visual stimulation during an eye movement would reach the colliculus, and c) the cells which differentiate also show a decreased responsiveness to visual stimulation during the time of background suppression. While this extraretinal signal has the characteristics one would expect of a corollary discharge, proprioception as a source of the signal cannot be excluded. 8. Cells which differentiate between the two stimulus conditions usually also show an enhanced response to a visual stimulus in their receptive field when it is to be the target for a saccadic eye movement. These cells in the superior colliculus receive an extraretinal input which permits them to differentiate betweent real stimulus movements and stimulus movements resulting from the monkey's own eye movements. This differentiation would provide an uncontaminated visual movement signal and facilitate the detection of real movement in the environment...
TL;DR: Lateral geniculate neurones of the cat were studied in terms of the latency for activation by local electrical stimulation of the retina, the latency of electrical activation from the visual cortex and properties of receptive fields to reveal the existence of slowly conducting axons relaying in the lateral geniculates nucleus.
Abstract: 1. Lateral geniculate neurones of the cat were studied in terms of the latency for activation by local electrical stimulation of the retina, the latency of electrical activation from the visual cortex and properties of receptive fields. Most of the units were relay cells (antidromic activation from visual cortex) but a small proportion were trans-synaptically activated from the cortex. The latter group included units with on-off, on-centre or off-centra receptive fields. 2. Direct activation of lateral geniculate neurones from local electrical stimulation of retinal ganglion cells or their axons in the retina was identified by the sharpness of timing of the elicited impulses. This procedure revealed the existence of slowly conducting axons relaying in the lateral geniculate nucleus. 3. The distribution of latencies for direct activation from the retina was bimodal with an extended tail of long values. It is similar to the distribution of antidromic latencies of retinal ganglion cells following stimulation of the optic tract. 4. There was a tendency for geniculate neurones with fast input from the retina to have fast axons to the visual cortex and correspondingly for medium-speed and slow input. 5. The previous classification of geniculate receptive fields into sustained and transient types was extended to include commonly encountered 'brisk' and uncommonly encountered 'sluggish' varieties of each. The extension was based on visual properties and latency for direct electrical activation from the retina. Units with receptive fields differing from the familiar on-centre or off-centre concentric pattern were encountered rarely; they included colour-coded fields, local-edge-detectors and one edge-inhibitory off-centre type.
TL;DR: Directionally sensitive ganglion cells in rabbit retina lose their directional sensitivity when picrotoxin, an antagonist of the inhibitory neurotransmitter gamma-aminobutyric acid, is infused into the retinal blood supply.
Abstract: Directionally sensitive ganglion cells in rabbit retina lose their directional sensitivity when picrotoxin, an antagonist of the inhibitory neurotransmitter gamma-aminobutyric acid, is infused into the retinal blood supply. Strychnine, an antagonist of glycine, does not produce this effect. Other receptive field types are affected by strychnine but not picrotoxin. Inhibitory transmitters therefore have specific functions in information processing in the retina.
TL;DR: Receptive-field properties of 214 neurons from cat striate cortex were studied to suggest that simple and complex cells analyze different aspects of a visual stimulus, and a hypothesis is provided which suggests that simple cells analyze input typically from one (or a few) geniculate neurons, while complex cells receive input from a larger region of geniculated neurons.
Abstract: 1. Receptive-field properties of 214 neurons from cat striate cortex were studied with particular emphasis on: a) classification, b) field size, c) orientation selectivity, d) direction selectivity...
TL;DR: Results imply that “latent” connections of some sort exist between afferents and cells in the gracile nucleus, and that these latent connections are unmasked by partial deafferentation, which is initially poor, but increases greatly with time.
TL;DR: The results of this study provide insight into the retinal connections which underlie ganglion cell receptive field organization and raise the possibility that transmembrane movements of chloride ions are critical for the light responsiveness of horizontal and depolarizing bipolar cell activity.
Abstract: Intracellular recordings from receptors, horizontal cells, bipolars, and amacrines have been carried out in the perfused mudpuppy eyecup. The introduction of a chloride-free (c-f) medium results in initial transient potential changes in many cells followed by a slow loss of light-evoked activity of the depolarizing bipolar, the horizontal cell, and the on depolarization of amacrine cells. The hyperpolarizing bipolar remains responsive to light stimulation in a c-f medium, but the antagonistic surround mechanism is abolished. These effects are reversible after returning to a normal ionic medium. The results of this study provide insight into the retinal connections which underlie ganglion cell receptive field organization. It is concluded that the depolarizing bipolar is excitatory to on ganglion cells and is also the pathway for on-excitation of on-off cells. The hyperpolarizing bipolar mediates the off discharge of off and on-off cells. Amacrine cells receive input from both depolarizing and hyperpolarizing bipolar cells. These findings raise the possibility that transmembrane movements of chloride ions are critical for the light responsiveness of horizontal and depolarizing bipolar cell activity.
TL;DR: Experimental tests of the on-off ganglion cell model favor the idea that this type of ganglions receives inhibitory input from amacrine cells and excitatory activation from depolarizing and hyperpolarizing bipolar cells.
Abstract: A chloride-free environment produces selective changes in the retinal network which include a separation of on and off channels. The identification of chloride-sensitive and insensitivie neuronal activity permits identification of some of the connections and intervening polarities of synaptic interactions which are expressed in ganglion cell receptive field organization. These experiments support previous suggestions that surround antagonism is dependent on horizontal cell activity. In addition they suggest a model of the neuronal connections which subserve on-center, off-center, and on-off ganglion cells. Experimental tests of the on-off ganglion cell model favor the idea that this type of ganglion cell receives inhibitory input from amacrine cells and excitatory activation from depolarizing and hyperpolarizing bipolar cells.
TL;DR: The results suggest that mechanical stimuli which would likely be encountered by the animal can lead to conduction block within its central nervous system and as a result modify its integrative activities.
Abstract: 1. In segmental ganglia of the leech, the cutaneous mechanosensory neurones responding to to touch innervated the skin of their own segment and of part of the anterior and posterior adjacent segments. Each touch receptive field could be divided into three non-overlapping areas: a central part innervated by the branches of the cell which ran in the nerve roots of the ganglion containing the cell body, and anterior and posterior parts innervated by its branches which ran in the nerve roots of the anterior and posterior adjacent ganglia. 2. Impulses originating from the anterior and posterior parts of the receptive fields were susceptible to conduction block within the central nervous system when the touch cells fired repetitively at frequencies that could readily be elicited with weak mechanical stimulation. In contrast, impulses originating from the central part of the receptive fields were less susceptible to block. 3. The morphology of touch cells revealed by intracellular injection of horseradish peroxidase suggested that conduction block occurred at specific bifurcation points where small cell processes joined the main process. Different physiological experiments supported this conclusion. 4. In some touch cells, bifurcation points with particularly low safety margins of conduction operated as low-pass filters, limiting the frequency of impulses capable of invading certain branches. 5. The results suggest that mechanical stimuli which would likely be encountered by the animal can lead to conduction block within its central nervous system and as a result modify its integrative activities.
TL;DR: The caudal extent of the terminal arborizations of dorsal root afferents was determined in adult cats by micro‐electrode stimulation within the dorsal horn and the recording on a distant dorsal root filament of the antidromic action potentials evoked by the stimulation of axons within the spinal cord.
Abstract: The caudal extent of the terminal arborizations of dorsal root afferents was determined in adult cats. The method used micro-electrode stimulation within the dorsal horn and the recording on a distant dorsal root filament of the antidromic action potentials evoked by the stimulation of axons within the spinal cord. 2. It was found that all filaments examined in the L2, 3 and 4 dorsal roots contained axons which projected at least as far as the S1 segment. The axons descended in or near the dorsal columns and from there penetrated into the grey matter. 3. The course of single fibres was followed to their apparent terminals. Thresholds, latencies and relative and absolute refractory periods were measured for single axons. These measurements confirmed that continuous axons ran from dorsal roots to distant segments and that the action potentials recorded were not dorsal root reflexes. 4. The majority of fibres with long range central arborizations were shown to have normal receptive fields in the dermatome of their parent dorsal root. They were not aberrant fibres leaving the spinal cord. 5. The long range afferents exist in substantial numbers since fifteen of eighty axons isolated by micro-electrode recording in the L2 dorsal root sent their axons as far as the S1 segment. The presence of these afferents from five segments away does not fit the data published on the inhibitory and excitatory receptive fields or dorsal horn cells which appear adequately explained by afferents arriving over nearby dorsal roots up to two segments away.
TL;DR: Evidence is presented that the streak is formed principally, but not entirely, by a concentration of small‐bodied ganglion cells with the receptive field properties and slow‐conducting axons typical of W‐cells.
Abstract: The properties of ganglion cells in the visual streak of the cat's retina have been investigated. Evidence is presented that the streak is formed principally, but not entirely, by a concentration of small-bodied ganglion cells with the receptive field properties and slow-conducting axons typical of W-cells.
TL;DR: Cells in V1 responded optimally to stimuli with very small or zero disparities, but cells in V2 frequently preferred disparities of several degrees crossed or uncrossed, according to their orientation preference and ocular dominance.
Abstract: 1. Units were recorded in the primary and secondary visual areas (V1 and V2) of the sheep. They were stimulated binocularly, using an adjustable prism to vary the disparity. 2. Cells in V1 responded optimally to stimuli with very small or zero disparities, but cells in V2 frequently preferred disparities of several degrees crossed or uncrossed. Many cells in V2 were particularly selective to disparity, often giving no response to a monocular stimulus. 3. Cells preferring the same disparity occur in discrete columns, about 400 muM wide. Changes between columns result from a step displacement of the receptive field of one eye. The disparities encoded in successive columns seem to follow a regular sequence: crossed, zero, uncrossed, zero, etc. 4. In both V1 and V2, cells are clustered, perhaps in columns, according to their orientation preference and ocular dominance. In V2, the constant disparity columns appear to be independent of the orientation clusters.
TL;DR: In this paper, the receptive-field properties of corticotectal cells in the monkey's striate cortex were studied using stationary and moving stimuli and it was shown that the cortical input to the superior colliculus is not directly responsible for the receptive field properties of collicular cells.
Abstract: 1. The receptive-field properties of corticotectal cells in the monkey's striate cortex were studied using stationary and moving stimuli. These cells were identified by antidromic activation from the superior colliculus. 2. Corticotectal cells form a relatively homogeneous group. They are found primarily in layers 5 and 6. These cells can usually be classified as CX-type cells but show broader orientation tuning, larger receptive fields, higher spontaneous activity, and greater binocular activation than CX-type cells do in general. A third of the corticotectal cells were direction selective. 3. These results suggest that the cortical input to the superior colliculus is not directly responsible for the receptive-field properties of collicular cells. We propose that this input has a gating function in contributing to the control of the downflow of excitation from the superficial to the deep layers of the colliculus.
TL;DR: It is concluded that the mesencephalic reticular formation of cats anesthetized with N2O and the effects of this stimulation on activity in the striate cortex are caused by a projection system which is organized in parallel to the specific projection and exerts a direct control over cortical excitability.
TL;DR: No evidence was found that the superior colliculus is involved in the functional reorganization presumed to occur following visual cortex ablation in infant cats, and recovery of visual behaviors following neonatal injury may therefore not involve alterations in the receptive fields of single cells.
Abstract: To determine if functional alterations in the superior colliculus might account for recovery of visual behaviors following visual cortex removal in infant cats, the receptive field characteristics of single units in the superior colliculus of cats whose visual cortex was removed within the first week of life were compared with those of cats which sustained visual cortex lesions in adulthood and with those of normal cats. In the normal superior colliculus, 90% of all cells responded to moving stimuli irrespective of shape or orientation. Sixty-four percent of these units were directionally selective, responding well to movement in one direction but poorly or not at all to movement in the opposite direction. Ninety percent of units were binocular, the vast majority of these responding equally to stimulation of either eye or showing only slight preference for stimulation of the contralateral eye. Responses to stationary flashes of light were observed in only 33% of all visually activated cells in the normal superior colliculus. After visual cortex ablation in adult cats, only six percent of movement sensitive cells were directionally selective. Binocular preference was shifted following adult visual cortex lesions such that sixty percent of all cells responded exclusively or predominantly to stimulation of the contralateral eye. Seventy-one percent of all visually responsive units responded to stationary lights flashed on or off within their receptive field boundaries. Lesions limited primarily to area 17 had the same effect as larger lesions of visual cortex. Infant visual cortex lesions resulted in receptive field alterations similar to those observed after adult ablation. Only fifteen percent of motion sensitive units were directionally selective. Seventy-one percent responded exclusively or predominantly to stimulation of the contralateral eye. Seventy-six percent of visually responsive cells were activated by stationary light. Lesions largely confined to area 17 produced the same alterations as more extensive lesions of visual cortex. Thus, no evidence was found that the superior colliculus is involved in the functional reorganization presumed to occur following visual cortex ablation in infant cats. Recovery of visual behaviors following neonatal injury may therefore not involve alterations in the receptive fields of single cells.
TL;DR: It is suggested that the region of contralateral postcranial representation plus the medial rhinarium and mystacial vibrissa areas are the homologue of SmII in placental mammals, and the area of bilateral representation is homologous to SmII of placental mammal, but that the lateral vibrissa and Rhinarium areas are a specialization of somatic sensory cortex unique to the Virginia opossum.
Abstract: Organization of opossum somatic sensory cortex has been investigated utilizing closely spaced microelectrode penetrations (0.25-0.5 mm apart) and delicate mechanical stimulation of body surfaces including the facial vibrissae. Results may be summarized as follows: (1) the general organization of somatic sensory cortex, as originally defined by Lende ('63a) has been confirmed; (2) a double representation of the contralateral mystacial vibrissae and rhinarium, implicit in Lende's original data, was revealed in detail, the two representations being orderly, adjacent, mirror-images of each other; (3) units at a given cortical locus responded to deflection of between one and five mystacial vibrissae, about half responding to movement of a single vibrissa only; (4) about 40% of mystacial vibrissa units showed a directional specificity to the extent that they responded to deflections in only one or two cardinal directions; (5) units located in the medial vibrissa area showed a greater directional specificity than did units located in the lateral vibrissa area; (6) the surface area of rhinarial receptive fields was about ten times the area of first-order rhinarial unit receptive fields (B. Pubols et al., '73); (7) representation of the contralateral forelimb, especially the ventral surface of the forepaw, is extensive, orderly, and precise; (8) representation of the contralateral hindlimb, foot, and tail is minimal, and is confined to the midline convexity; (9) the presence of a small region of bilateral representation, lateral to the regions of contralateral representation, was confirmed. It is suggested that the region of contralateral postcranial representation plus the medial rhinarium and mystacial vibrissa areas are the homologue of SmI in placental mammals, and the region of bilateral representation is homologous to SmII of placental mammals, but that the lateral vibrissa and rhinarium areas are a specialization of somatic sensory cortex unique to the Virginia opossum.