Visual receptive fields and their images in superior colliculus of the cat

1975 ◽  
Vol 38 (2) ◽  
pp. 219-230 ◽  
Author(s):  
J. T. McIlwain

1. The receptive fields of collicular neurons in the cat, recorded in a single microelectrode penetration, were not centered on a point in visual space, but nested eccentrically with the smaller fields displaced toward the area centralis. The eccentric nesting was not eliminated by correcting the fields for the tangent screen distortion or by making penetrations normal to the collicular surface in coronal and parasagittal planes. These findings do not support the idea that collicular cells form topographically organized columns oriented normal to the collicular surface. 2. When the receptive fields were plotted in the visual coordinate system of the collicular map, the nesting became much more concentric, suggesting that the eccentric nesting of the receptive fields in visual space was largely a product of the retinotectal coordinate transformation. 3. The profile of a collicular receptive field, plotted in the collicular visual coordinate system is called the receptive-field image. Receptive-field images tended to have oval shapes with the long axis oriented mediolaterally. Clusters of receptive-field images, plotted for single penetrations, appeared similar wherever they occurred in the collicular map, suggesting that a common pattern of neural convergence determines the geometry of the receptive-field images in all parts of the colliculus. 4. The neural substrate of the receptive-field images was examined by tracing the theoretical patterns of neural activity which a point stimulus would produce in the retinotectal system. This analysis suggested that the shape and dimensions of the receptive-field images, and consequently the receptive fields, might be accounted for in large part by the geometry of collicular dendritic fields, the dimensions of the visual receptive fields of afferent fibers, and the retinotectal coordinate transformation. 5. Because it adjusts for the retinotectal distortion of visual space, the receptive-field image may be used to outline the distribution of collicular cells excited by a point stimulus. This makes it possible to show that a point stimulus activates large-field cells in the superficial gray layer over an area of about 2.5 by 1.5 mm in the central parts of the colliculus. It is suggested that such cells may organize the directional signals required by the oculomotor system for visual orienting behavior.

2014 ◽  
Vol 112 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Xiaodong Chen ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki

The ventral intraparietal area (VIP) processes multisensory visual, vestibular, tactile, and auditory signals in diverse reference frames. We recently reported that visual heading signals in VIP are represented in an approximately eye-centered reference frame when measured using large-field optic flow stimuli. No VIP neuron was found to have head-centered visual heading tuning, and only a small proportion of cells had reference frames that were intermediate between eye- and head-centered. In contrast, previous studies using moving bar stimuli have reported that visual receptive fields (RFs) in VIP are head-centered for a substantial proportion of neurons. To examine whether these differences in previous findings might be due to the neuronal property examined (heading tuning vs. RF measurements) or the type of visual stimulus used (full-field optic flow vs. a single moving bar), we have quantitatively mapped visual RFs of VIP neurons using a large-field, multipatch, random-dot motion stimulus. By varying eye position relative to the head, we tested whether visual RFs in VIP are represented in head- or eye-centered reference frames. We found that the vast majority of VIP neurons have eye-centered RFs with only a single neuron classified as head-centered and a small minority classified as intermediate between eye- and head-centered. Our findings suggest that the spatial reference frames of visual responses in VIP may depend on the visual stimulation conditions used to measure RFs and might also be influenced by how attention is allocated during stimulus presentation.


2017 ◽  
Author(s):  
Ghislain St-Yves ◽  
Thomas Naselaris

AbstractWe introduce the feature-weighted receptive field (fwRF), an encoding model designed to balance expressiveness, interpretability and scalability. The fwRF is organized around the notion of a feature map—a transformation of visual stimuli into visual features that preserves the topology of visual space (but not necessarily the native resolution of the stimulus). The key assumption of the fwRF model is that activity in each voxel encodes variation in a spatially localized region across multiple feature maps. This region is fixed for all feature maps; however, the contribution of each feature map to voxel activity is weighted. Thus, the model has two separable sets of parameters: “where” parameters that characterize the location and extent of pooling over visual features, and “what” parameters that characterize tuning to visual features. The “where” parameters are analogous to classical receptive fields, while “what” parameters are analogous to classical tuning functions. By treating these as separable parameters, the fwRF model complexity is independent of the resolution of the underlying feature maps. This makes it possible to estimate models with thousands of high-resolution feature maps from relatively small amounts of data. Once a fwRF model has been estimated from data, spatial pooling and feature tuning can be read-off directly with no (or very little) additional post-processing or in-silico experimentation.We describe an optimization algorithm for estimating fwRF models from data acquired during standard visual neuroimaging experiments. We then demonstrate the model’s application to two distinct sets of features: Gabor wavelets and features supplied by a deep convolutional neural network. We show that when Gabor feature maps are used, the fwRF model recovers receptive fields and spatial frequency tuning functions consistent with known organizational principles of the visual cortex. We also show that a fwRF model can be used to regress entire deep convolutional networks against brain activity. The ability to use whole networks in a single encoding model yields state-of-the-art prediction accuracy. Our results suggest a wide variety of uses for the feature-weighted receptive field model, from retinotopic mapping with natural scenes, to regressing the activities of whole deep neural networks onto measured brain activity.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jan H. Kirchner ◽  
Julijana Gjorgjieva

AbstractSynaptic inputs on cortical dendrites are organized with remarkable subcellular precision at the micron level. This organization emerges during early postnatal development through patterned spontaneous activity and manifests both locally where nearby synapses are significantly correlated, and globally with distance to the soma. We propose a biophysically motivated synaptic plasticity model to dissect the mechanistic origins of this organization during development and elucidate synaptic clustering of different stimulus features in the adult. Our model captures local clustering of orientation in ferret and receptive field overlap in mouse visual cortex based on the receptive field diameter and the cortical magnification of visual space. Including action potential back-propagation explains branch clustering heterogeneity in the ferret and produces a global retinotopy gradient from soma to dendrite in the mouse. Therefore, by combining activity-dependent synaptic competition and species-specific receptive fields, our framework explains different aspects of synaptic organization regarding stimulus features and spatial scales.


2017 ◽  
Vol 114 (29) ◽  
pp. E5979-E5985 ◽  
Author(s):  
Sujaya Neupane ◽  
Daniel Guitton ◽  
Christopher C. Pack

Oscillations are ubiquitous in the brain, and they can powerfully influence neural coding. In particular, when oscillations at distinct sites are coherent, they provide a means of gating the flow of neural signals between different cortical regions. Coherent oscillations also occur within individual brain regions, although the purpose of this coherence is not well understood. Here, we report that within a single brain region, coherent alpha oscillations link stimulus representations as they change in space and time. Specifically, in primate cortical area V4, alpha coherence links sites that encode the retinal location of a visual stimulus before and after a saccade. These coherence changes exhibit properties similar to those of receptive field remapping, a phenomenon in which individual neurons change their receptive fields according to the metrics of each saccade. In particular, alpha coherence, like remapping, is highly dependent on the saccade vector and the spatial arrangement of current and future receptive fields. Moreover, although visual stimulation plays a modulatory role, it is neither necessary nor sufficient to elicit alpha coherence. Indeed, a similar pattern of coherence is observed even when saccades are made in darkness. Together, these results show that the pattern of alpha coherence across the retinotopic map in V4 matches many of the properties of receptive field remapping. Thus, oscillatory coherence might play a role in constructing the stable representation of visual space that is an essential aspect of conscious perception.


1985 ◽  
Vol 54 (4) ◽  
pp. 1068-1083 ◽  
Author(s):  
J. Duysens ◽  
G. A. Orban ◽  
J. Cremieux ◽  
H. Maes

In 149 units from area 17 and 48 units from area 18 the responses to stationary stimulation of different durations were compared with the responses to the same stimulus (a 0.3 degrees-wide light or dark bar) moving at different velocities. The aim was to test the hypothesis that the range of effective velocities depends on the time needed for the bar to cross the receptive field. Forty-two percent of the area 17 cells and 8% of the area 18 cells responded poorly or not at all to briefly presented stationary stimulation. These cells were unable to respond at high velocities, and for these "duration-sensitive" cells the velocity characteristics are well predicted on the basis of responses to stationary stimulation of different durations. Cells that responded equally well to periods of stationary stimulation ranging from 12.5 to 3,200 ms ("duration-insensitive cells") were found to be able to respond at all equivalent velocities, but their preference for either high, low, or intermediate velocities was not reflected in differences in responsiveness to the different durations tested. Duration-sensitive cells in area 17 tended to have a receptive field near the area centralis, and 73% of them were classified as S-family cells, one third being end-stopped S-cells. In contrast only 18% of the duration-insensitive cells were of the S family, and these S-family cells were rarely end-stopped (1/12) or rarely had receptive fields within 5 degrees of the fovea (3/12). Duration-sensitive cells had very long latencies (median 285 ms) in response to a stationary flashed light bar of 1 s duration but much shorter latencies (median 91 ms) when tested with a slowly moving light bar. This difference was not seen in duration-insensitive cells (median latencies = 61 and 59 ms). The ability to respond at high velocity was contrast dependent. At a low contrast level all cells failed to respond to brief stimulation, whether moving or stationary. At high contrast levels only the duration-insensitive cells showed an increased responsivity to brief stimuli. The absence of responses in duration-sensitive cells to brief stimuli of high contrast may depend upon suppressive influences reaching these cells before the excitatory influences. We conclude that the velocity upper cutoff of most S-family cells with a central receptive field can be predicted from a knowledge of the minimum duration of stationary presentation required for their activation (median ON duration threshold, 200 ms).(ABSTRACT TRUNCATED AT 400 WORDS)


Author(s):  
Andreas J Keller ◽  
Morgane M Roth ◽  
Massimo Scanziani

We sense our environment through pathways linking sensory organs to the brain. In the visual system, these feedforward pathways define the classical feedforward receptive field (ffRF), the area in space where visual stimuli excite a neuron1. The visual system also uses visual context, the visual scene surrounding a stimulus, to predict the content of the stimulus2, and accordingly, neurons have been found that are excited by stimuli outside their ffRF3–8. The mechanisms generating excitation to stimuli outside the ffRF are, however, unclear. Here we show that feedback projections onto excitatory neurons in mouse primary visual cortex (V1) generate a second receptive field driven by stimuli outside the ffRF. Stimulating this feedback receptive field (fbRF) elicits slow and delayed responses compared to ffRF stimulation. These responses are preferentially reduced by anesthesia and, importantly, by silencing higher visual areas (HVAs). Feedback inputs from HVAs have scattered receptive fields relative to their putative V1 targets enabling the generation of the fbRF. Neurons with fbRFs are located in cortical layers receiving strong feedback projections and are absent in the main input layer, consistent with a laminar processing hierarchy. The fbRF and the ffRF are mutually antagonistic since large, uniform stimuli, covering both, suppress responses. While somatostatin-expressing inhibitory neurons are driven by these large stimuli, parvalbumin and vasoactive-intestinal-peptide-expressing inhibitory neurons have antagonistic fbRF and ffRF, similar to excitatory neurons. Therefore, feedback projections may enable neurons to use context to predict information missing from the ffRF and to report differences in stimulus features across visual space, regardless if excitation occurs inside or outside the ffRF. We have identified a fbRF which, by complementing the ffRF, may contribute to predictive processing.


Perception ◽  
1988 ◽  
Vol 17 (6) ◽  
pp. 819-825
Author(s):  
Bernard Moulden ◽  
David Martin

A cheap (under £100 at current prices) and simple analogue device is described which permits one to demonstrate, according to an adjustable configuration of the photoreceptive elements, some of the main properties of (i) circularly-symmetrical, (ii) ‘simple’ elongated opponent-flank, and (iii) multiple-discharge-centre visual receptive fields. The design and construction of the device are described, together with some suggested demonstrations.


1991 ◽  
Vol 66 (5) ◽  
pp. 1624-1641 ◽  
Author(s):  
D. P. Munoz ◽  
D. Guitton

1. We recorded from electrophysiologically identified output neurons of the superior colliculus (SC)--tectoreticular and tectoreticulospinal neurons [together called TR(S)Ns]--in the alert cat with head either unrestrained or immobilized. A cat actively exploring its visual surrounds typically makes a series of coordinated eye-head orienting movements that rapidly shift the visual axis from one point to another. These single-step shifts in gaze position (gaze = eye-in-space = eye-in-head + head-in-space) are separated by periods in which the visual axis remains stationary with respect to surrounding space. 2. Eighty-seven percent (86/99) of the TR(S)Ns studied during periods when the visual axis was stationary presented a sustained discharge, the intensity of which depended on the magnitude and direction of the vector drawn between current gaze position and the gaze position required to fixate a target of interest (gaze position error or GPE). The maximum sustained discharge recorded from each TR(S)N corresponded to a specific GPE vector and was correlated with the cell's position on the SC's retinotopically coded motor map. 3. The 86 TR(S)Ns could be divided into two classes. ,Fixation TR(S)Ns- [fTR(S)Ns, n = 12] discharged maximally when the animal attentively fixated a target of interest, (i.e. GPE = 0 degrees). These neurons were located in the rostral SC and had visual receptive fields that included a representation of the area centralis. “Orientation TR(S)Ns” [oTR(S)Ns, n = 62] had visual receptive fields that excluded the area centralis and discharged for nonzero GPEs. The oTR(S)Ns were recorded more caudally on the SC's map. 4. For a given value of GPE, an ensemble of TR(S)Ns was active. When the cat changed its gaze position relative to a fixed target of interest, the zone of sustained activity shifted to a new collicular site. Thus, to maintain the maximum sustained discharge of a TR(S)N when target position was changed relative to the fixed body, it was necessary that gaze move to a new position that reestablished the preferred GPE. 5. The areal extent of GPEs for which a TR(S)N discharged defined a gaze position error field (GPEF) that was approximately coaligned with the cell's visual receptive field. The maximum sustained discharge occurred when GPE corresponded approximately to the center of the cell's GPEF. 6. The diameter of a TR(S)N's GPEF was related to the magnitude of that cell's optimal GPE. fTR(S)Ns had the smallest GPEFs, approximately 15-20 degrees; GPEF diameter was larger for oTR(S)Ns.(ABSTRACT TRUNCATED AT 400 WORDS)


1997 ◽  
Vol 77 (5) ◽  
pp. 2268-2292 ◽  
Author(s):  
Michael S. A. Graziano ◽  
Xin Tian Hu ◽  
Charles G. Gross

Graziano, Michael S. A., Xin Tian Hu, and Charles G. Gross. Visuospatial properties of ventral premotor cortex. J. Neurophysiol. 77: 2268–2292, 1997. In macaque ventral premotor cortex, we recorded the activity of neurons that responded to both visual and tactile stimuli. For these bimodal cells, the visual receptive field extended from the tactile receptive field into the adjacent space. Their tactile receptive fields were organized topographically, with the arms represented medially, the face represented in the middle, and the inside of the mouth represented laterally. For many neurons, both the visual and tactile responses were directionally selective, although many neurons also responded to stationary stimuli. In the awake monkeys, for 70% of bimodal neurons with a tactile response on the arm, the visual receptive field moved when the arm was moved. In contrast, for 0% the visual receptive field moved when the eye or head moved. Thus the visual receptive fields of most “arm + visual” cells were anchored to the arm, not to the eye or head. In the anesthetized monkey, the effect of arm position was similar. For 95% of bimodal neurons with a tactile response on the face, the visual receptive field moved as the head was rotated. In contrast, for 15% the visual receptive field moved with the eye and for 0% it moved with the arm. Thus the visual receptive fields of most “face + visual” cells were anchored to the head, not to the eye or arm. To construct a visual receptive field anchored to the arm, it is necessary to integrate the position of the arm, head, and eye. For arm + visual cells, the spontaneous activity, the magnitude of the visual response, and sometimes both were modulated by the position of the arm (37%), the head (75%), and the eye (58%). In contrast, to construct a visual receptive field that is anchored to the head, it is necessary to use the position of the eye, but not of the head or the arm. For face + visual cells, the spontaneous activity and/or response magnitude was modulated by the position of the eyes (88%), but not of the head or the arm (0%). Visual receptive fields anchored to the arm can encode stimulus location in “arm-centered” coordinates, and would be useful for guiding arm movements. Visual receptive fields anchored to the head can likewise encode stimuli in “head-centered” coordinates, useful for guiding head movements. Sixty-three percent of face + visual neurons responded during voluntary movements of the head. We suggest that “body-part-centered” coordinates provide a general solution to a problem of sensory-motor integration: sensory stimuli are located in a coordinate system anchored to a particular body part.


2001 ◽  
Vol 86 (3) ◽  
pp. 1179-1194 ◽  
Author(s):  
L. Huang ◽  
S. L. Pallas

Partial ablation of the superior colliculus (SC) at birth in hamsters compresses the retinocollicular map, increasing the amount of visual field represented at each SC location. Receptive field sizes of single SC neurons are maintained, however, preserving receptive field properties in the prelesion condition. The mechanism that allows single SC neurons to restrict the number of convergent retinal inputs and thus compensate for induced brain damage is unknown. In this study, we examined the role of N-methyl-d-aspartate (NMDA) receptors in controlling retinocollicular convergence. We found that chronic 2-amino-5-phosphonovaleric acid (APV) blockade of NMDA receptors from birth in normal hamsters resulted in enlarged single-unit receptive fields in SC neurons from normal maps and further enlargement in lesioned animals with compressed maps. The effect was linearly related to lesion size. These results suggest that NMDA receptors are necessary to control afferent/target convergence in the normal SC and to compensate for excess retinal afferents in lesioned animals. Despite the alteration in receptive field size in the APV-treated animals, a complete visual map was present in both normal and lesioned hamsters. Visual responsiveness in the treated SC was normal; thus the loss of compensatory plasticity was not due to reduced visual responsiveness. Our results argue that NMDA receptors are essential for map refinement, construction of receptive fields, and compensation for damage but not overall map compression. The results are consistent with a role for the NMDA receptor as a coincidence detector with a threshold, providing visual neurons with the ability to calculate the amount of visual space represented by competing retinal inputs through the absolute amount of coincidence in their firing patterns. This mechanism of population matching is likely to be of general importance during nervous system development.


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