Showing papers on "Orientation column published in 2015"
TL;DR: It is shown that cells with similar orientation preferences form large patches that span the vertical thickness of the retinorecipient layers in the mouse superior colliculus, a finding with implications for behavioural responses mediated by this brain centre.
Abstract: More than twenty types of retinal ganglion cells conduct visual information from the eye to the rest of the brain. Each retinal ganglion cell type tessellates the retina in a regular mosaic, so that every point in visual space is processed for visual primitives such as contrast and motion. This information flows to two principal brain centres: the visual cortex and the superior colliculus. The superior colliculus plays an evolutionarily conserved role in visual behaviours, but its functional architecture is poorly understood. Here we report on population recordings of visual responses from neurons in the mouse superior colliculus. Many neurons respond preferentially to lines of a certain orientation or movement axis. We show that cells with similar orientation preferences form large patches that span the vertical thickness of the retinorecipient layers. This organization is strikingly different from the randomly interspersed orientation preferences in the mouse’s visual cortex; instead, it resembles the orientation columns observed in the visual cortices of large mammals. Notably, adjacent superior colliculus orientation columns have only limited receptive field overlap. This is in contrast to the organization of visual cortex, where each point in the visual field activates neurons with all preferred orientations. Instead, the superior colliculus favours specific contour orientations within ~30° regions of the visual field, a finding with implications for behavioural responses mediated by this brain centre.
102 citations
TL;DR: Evidence is provided that the organization of the mouse visual system shares important similarities to that of primates and opens the possibility of using mice to probe motion computation mechanisms.
90 citations
TL;DR: It is shown that in the mouse there is also a precise organization of orientation preference, which makes the superior colliculus different from visual cortex and unsuitable for translation-invariant object recognition and suggests that visual stimuli might have different behavioural consequences depending on their retinotopic location.
Abstract: The superior colliculus is a layered structure important for body- and gaze-orienting responses. Its superficial layer is, next to the lateral geniculate nucleus, the second major target of retinal ganglion axons and is retinotopically organized. Here we show that in the mouse there is also a precise organization of orientation preference. In columns perpendicular to the tectal surface, neurons respond to the same visual location and prefer gratings of the same orientation. Calcium imaging and extracellular recording revealed that the preferred grating varies with retinotopic location, and is oriented parallel to the concentric circle around the centre of vision through the receptive field. This implies that not all orientations are equally represented across the visual field. This makes the superior colliculus different from visual cortex and unsuitable for translation-invariant object recognition and suggests that visual stimuli might have different behavioural consequences depending on their retinotopic location.
65 citations
TL;DR: It is concluded that columnar organization for visual space is not only defined by the spatial location of the stimulus, but also by absolute phase, which suggests that this phase-visuotopy is responsible for the emergence of orientation maps.
Abstract: Earlier work suggests that spatial phase preferences are randomly distributed throughout visual cortex. In this study, the authors present evidence towards a columnar organization for spatial phase that resembles organization for orientation preference, which suggests that this phase organization may contribute to the emergence of orientation maps.
51 citations
TL;DR: This work proposes that a cortical network of feedforward and intracortical lateral connections elaborates a full set of optimum orientations from geniculate inputs that show a bias to stimulus orientation and form a set of two or a small number of 'Cartesian' coordinates.
33 citations
TL;DR: It is shown that after applying an adapter away from the tested cells, neurons whose receptive fields were located remotely from the adapted site also exhibit a novel selectivity in spite of the fact that they were not adapted, suggesting that orientation columns transcend anatomy, and are almost strictly functionally dynamic.
Abstract: Cortical organization rests upon the fundamental principle that neurons sharing similar properties are co-located. In the visual cortex, neurons are organized into orientation columns. In a column, most neurons respond optimally to the same axis of an oriented edge, that is, the preferred orientation. This orientation selectivity is believed to be absolute in adulthood. However, in a fully mature brain, it has been established that neurons change their selectivity following sensory experience or visual adaptation. Here, we show that after applying an adapter away from the tested cells, neurons whose receptive fields were located remotely from the adapted site also exhibit a novel selectivity in spite of the fact that they were not adapted. These results indicate a robust reconfiguration and remapping of the orientation domains with respect to each other thus removing the possibility of an orientation hole in the new hypercolumn. These data suggest that orientation columns transcend anatomy, and are almost strictly functionally dynamic.
22 citations
02 Apr 2015
TL;DR: A novel general framework for line segment perception, which is motivated by a biological visual cortex, and requires no parameter tuning is proposed, which outperforms the existing methods in the balance between conciseness and completeness.
Abstract: This paper proposes a novel general framework for line segment perception, which is motivated by a biological visual cortex, and requires no parameter tuning. In this framework, we design a model to approximate receptive fields of simple cells. More importantly, the structure of biological orientation columns is imitated by organizing artificial complex and hypercomplex cells with the same orientation into independent arrays. Besides, an interaction mechanism is implemented by a set of self-organization rules. Enlightened by the visual topological theory, the outputs of these artificial cells are integrated to generate line segments that can describe nonlocal structural information of images. Each line segment is evaluated quantitatively by its significance. The computation complexity is also analyzed. The proposed method is tested and compared to state-of-the-art algorithms on real images with complex scenes and strong noises. The experiments demonstrate that our method outperforms the existing methods in the balance between conciseness and completeness.
16 citations
TL;DR: It is found that the orientation preferences of the afferents matched closely with those of the cells in the orientation domains that they terminated in (Pearson's r = 0.633, n = 22, P =0.002) suggests a possible subcortical origin for cortical orientation selectivity.
Abstract: The primary visual cortex of carnivores and primates shows an orderly progression of domains of neurons that are selective to a particular orientation of visual stimuli such as bars and gratings. We recorded from single-thalamic afferent fibers that terminate in these domains to address the issue whether the orientation sensitivity of these fibers could form the basis of the remarkable orientation selectivity exhibited by most cortical cells. We first performed optical imaging of intrinsic signals to obtain a map of orientation domains on the dorsal aspect of the anaesthetized cat's area 17. After confirming using electrophysiological recordings the orientation preferences of single neurons within one or two domains in each animal, we pharmacologically silenced the cortex to leave only the afferent terminals active. The inactivation of cortical neurons was achieved by the superfusion of either kainic acid or muscimol. Responses of single geniculate afferents were then recorded by the use of high impedance electrodes. We found that the orientation preferences of the afferents matched closely with those of the cells in the orientation domains that they terminated in (Pearson's r = 0.633, n = 22, P = 0.002). This suggests a possible subcortical origin for cortical orientation selectivity.
13 citations
TL;DR: It is shown that the accuracy of decoding of spiral patterns in V1 can be predicted by a voxel's preferred spatial position and its coarse orientation preference, suggesting that coarse-scale biases are sufficient for orientation decoding.
Abstract: Orientation signals in human primary visual cortex (V1) can be reliably decoded from the multivariate pattern of activity as measured with functional magnetic resonance imaging (fMRI) The precise
11 citations
TL;DR: It is suggested that contrast‐ and orientation‐sensitive variability not only explains the contrast invariance observed in the LGN but can also underlie the contrast‐invariant orientation tuning seen at the level of the primary visual cortex.
Abstract: Responses of most neurons in the primary visual cortex of mammals are markedly selective for stimulus orientation and their orientation tuning does not vary with changes in stimulus contrast. The basis of such contrast invariance of orientation tuning has been shown to be the higher variability in the response for low-contrast stimuli. Neurons in the lateral geniculate nucleus (LGN), which provides the major visual input to the cortex, have also been shown to have higher variability in their response to low-contrast stimuli. Parallel studies have also long established mild degrees of orientation selectivity in LGN and retinal cells. In our study, we show that contrast invariance of orientation tuning is already present in the LGN. In addition, we show that the variability of spike responses of LGN neurons increases at lower stimulus contrasts, especially for non-preferred orientations. We suggest that such contrast- and orientation-sensitive variability not only explains the contrast invariance observed in the LGN but can also underlie the contrast-invariant orientation tuning seen at the level of the primary visual cortex.
TL;DR: Retrochiasmal visual pathways include optic tracts, lateral geniculate nuclei, optic radiations, and striate cortex (V1), which are responsible for perception of objects, faces, colors, and orientation.
01 Jan 2015
TL;DR: The complex functional organization of primary visual cortex has been revealed by animal studies using several invasive methods including electrical recordings and optical imaging to noninvasively reveal the retinotopic organization ofPrimary visual cortex in the human brain.
Abstract: The complex functional organization of primary visual cortex has been revealed by animal studies using several invasive methods including electrical recordings and optical imaging. These studies have revealed that V1 neurons have small receptive fields responding to many visual features including oriented luminance contrast edges, wavelength of light, visual motion, and spatial frequency that form the basis of (dynamic) shape and color perception. Tangentially along the cortex, neurons are organized at different scales ranging from retinotopically organized visual field maps in the cm range to columnar organization in the hundreds of microns range. Besides these lateral organization principles, primary visual cortex exhibits also a detailed vertical organization of six major cortical laminae. With the advent of functional MRI it has become possible to noninvasively reveal the retinotopic organization of primary visual cortex in the human brain. With ultrahigh field MRI scanners, it is even possible to map orientation columns and cortical layers at submillimeter resolution.
TL;DR: The intricate relationship between luminance polarity and orientation selectivity in the upper layers of ferret visual cortex is revealed, revealing the fate of ON-OFF receptive field segregation in the visual cortex.
TL;DR: 2-photon imaging of GCamP6s calcium fluorescent signals is used to map the receptive fields of thousands of neurons in layer 2/3 of tree shrew visual cortex with reverse correlation using sparse noise to suggest the differential arrangement of ON and OFF subfield centers meets the conjoint constraints of mapping both visuotopy and orientation in a single population of neurons.
Abstract: In vivo 2-photon imaging of calcium sensors in visual cortex has provided a host of new insights into the fine scale columnar mapping of response properties like orientation, direction, and visual space. Extracellular recording in carnivores have shown a columnar segregation of ON- and OFF-center geniculate inputs in layer 4, which could provide the basis for the generation of orientation selectivity. However, the spatial arrangement of ON and OFF in layer 2/3 has not been addressed. In this study we used 2-photon imaging of GCamP6s calcium fluorescent signals to map the receptive fields of thousands of neurons in layer 2/3 of tree shrew visual cortex with reverse correlation using sparse noise. We found a diverse array of receptive field properties in layer 2/3 including neurons with classic simple, complex and single sign receptive fields (either ON or OFF). The ON and OFF subfields in layer 2/3 were found to exhibit topologically distinct relationships with the maps of visual space and orientation preference. In most cases, the centers of OFF subfields for neurons in a given region of cortex were confined to a compact region of visual space and displayed a smooth retinotopic progression, while the centers of the ON subfields were distributed over a wider region of visual space and displayed less retinotopic precision. Consistent with the arrangement of ON and OFF subfields of simple cells in other species, the angle of displacement in visual space of the ON and OFF subfields for individual neurons could be used to predict the organization of the orientation map. Taken together, these results suggest that the differential arrangement of ON and OFF subfield centers by cortical circuits meets the conjoint constraints of mapping both visuotopy and orientation in a single population of neurons and in a fashion that preserves continuity for both stimulus features. Meeting abstract presented at VSS 2015.
Dissertation•
01 Jan 2015
TL;DR: This work examined orientation and direction selectivity in LGN and V1 neurons of a highly visual diurnal rodent: the gray squirrel, and results suggest that the contribution of orientation-and direction-selective channels from the LGN to V1 is small.
Abstract: Classic studies of lateral geniculate nucleus (LGN) and visual cortex (V1) in carnivores and primates have found that a majority of neurons in LGN exhibit a center-surround organization, while V1 neurons exhibit strong orientation selectivity and, in many species, direction selectivity. This has led to the prevailing model that orientation and direction selectivity are computed anew in the cortex. However, recent work in mice has indicated that direction-selective cells from the retina project directly to the LGN, and some species may have orientation and direction selectivity in the LGN. To examine whether LGN cells make a substantial contribution to cortical orientation selectivity, we examined orientation and direction selectivity in LGN and V1 neurons of a highly visual diurnal rodent: the gray squirrel. Although direction selectivity was weak overall, LGN layers 3abc exhibited elevated direction selectivity index values compared to LGN layers 1 and 2. These results suggest that, for central visual fields, the contribution of orientation-and direction-selective channels from the LGN to V1 is small in the squirrel. However, orientation and direction selectivity that may be found transiently during development, and might seed cortical orientation or direction selectivity, has yet to be studied. We performed electrophysiological records on ferrets at eye opening (P30-35). Preliminary results indicate that the developing LGN may exhibit some orientation and direction selectivity. Future experiments will involve collecting more data from ferrets early in development, at around the time of opening. The primary visual cortex (V1) is the first site in the primate visual system where there are close correspondences between the response properties of neurons and perceptual behaviors of the animal, making it a critical area for the study of cortical circuitry. Two fundamental response properties of neurons in V1 are the selectivity to stimulus orientation and direction. In this work, we will review the visual pathways, development, and models for the circuit origins of these computations in V1 and its antecedent structures, in particular the lateral geniculate nucleus (LGN). Finally, we will describe the direction of our research addressing this field. Orientation selectivity, the preferential response of neurons to a stimulus (such as a bar of light) oriented at a particular angle, was first described in the primary visual cortex of the cat and has since been found in V1 in all examined mammals (Hubel and display a further type of selectivity for the stimulus direction of motion, or direction selectivity, in which the …
06 Aug 2015
TL;DR: In this article, the orientation columns are composed of an array of orientation detectors and the resulting orientation is derived at the sample level of the input seismic data: the filter response competes with each other in the array, and the maximum response defines the seismic orientation.
Abstract: In this paper, we introduce a method of orientation estimation in seismic data. Unlike conventional methods of orientation estimation with a context window, our method is inspired by the neural mechanism of visual perception. The primary visual cortex in the brain contains orientation columns, which are composed of an array of orientation detectors. A log-Gabor filter with a specific orientation and scale configuration simulates the neuronal mechanism of the orientation detector, while an array of such filters simulates the orientation columns. The resulting orientation is derived at the sample level of the input seismic data: the filter response competes with each other in the array, and the maximum response defines the seismic orientation. Our proposed method has many applications in seismic interpretation, e.g., calculating the volumetric azimuth and dip attributes without picking, guiding seismic attribute computation, and detecting seismic texture patterns.
01 Jan 2015
01 Jan 2015