Visual Submodalities Research Articles

Полимодальность как черта когнитивного стиля автора в изобразительном регистре англоязычного художественного текста (на материале произведений Дж. Стейнбека)

The study discusses multimodal perceptual situations presented in a literary text as a feature of the author’s mind style. The perceptual component of world perception is considered to be the result of unique perceptual experience, thus it is argued that the perceptual component of the text structure reflects the mind style of its author. The analysis of the situation of perception provided in the paper is based on the concept of speech registers. A speech register implemented in a text appears as a model of the speaker’s worldview that determines the language means used in the text in accordance with the communicative situation, and vice versa, makes it possible to identify the features of the perception of reality based on the lingual means used by the author. The research is based on data obtained from a number of J. Steinbeck’s literary works totaling 830 pages. The research methods used include componential, contextual, and linguo-stylistic analysis. The analysis prompts the following conclusions: multimodality within a literary text is conveyed through the use of a variety of lexical, phonetic, syntactic lingual means as well as expressive means based on conceptual metaphors with visual, auditory, olfactory, and tactile semantic components, thus evoking corresponding planes of perception. Perceptual images depicted in the descriptive register help convey the ideas, the topics raised in a literary work, serve as a means of text composition, and create a cinematic effect within the text. The abovementioned testifies to the distinctiveness of the author’s mind style, which manifests itself in the representation of perceptual experience through various modalities simultaneously, in synesthetic metaphors, multimodal presentation of the results of perception by visual submodalities.

Invited Session V: GABAergic function and dysfunction in visual perception: Strong evidence against a common center-surround mechanism in visual processing

Events and objects in the world generally do not occur in isolation. This surrounding spatial and temporal information has major effects on visual processing, effects that are typically described as contextual modulations. Given qualitative similarities among various contextual surround effects (e.g., the effects tend to exaggerate differences and suppress uniform stimuli), it might seem intuitive that these processes are related. It is unknown, however, whether contextual modulation processes across visual sub-modalities are independent, or at least in part share a common underlying mechanism. This is especially relevant for clinical work where these contextual effects are often linked to inhibitory function. We addressed this question using an individual differences approach in three different populations (total N = 129): neurotypical adults, older adults and patients with schizophrenia. The context battery included six tasks that assessed surround modulations in luminance, contrast, orientation, motion (2X) and size domains. The results revealed robust contextual effects across all tasks. However, despite large sample sizes, we found no significant correlations among different contextual tasks. Across groups, we did find significant differences: (a) weaker surround contrast effect in both schizophrenia and older adults, (b) stronger repulsive surround tilt and motion effects in older adults and (c) weaker surround suppression for motion in both schizophrenia and older adults. We find that (1) strength of contextual modulation does not correlate across visual sub-modalities and (2) deficits in contextual modulation that go in different directions. Together, this indicates an absence of a common underlying mechanism for contextual modulation in vision.

Midlevel visual deficits after strokes involving area human V4

We present the results of 51 stroke patients with free central visual fields of which about half suffer from clear deficits of midlevel vision undetected by standard clinical tests. These patients yield significantly elevated thresholds for detection and/or discrimination between forms defined by motion, colour, or line orientation (‘texture’). As demonstrated by voxel-based lesion-symptom mapping (VLSM) the underlying lesions involve mainly area human V4 (hV4) located in the posterior third of the fusiform gyrus and extending into the lingual gyrus.Patient's detection thresholds correlate only very weakly between the submodalities tested, indicating partly separate neural networks on mid-level vision for colour, motion, and texture detection. Correlations are far stronger for form discrimination tasks, indicating partly shared mechanisms for even simple form discrimination of distinct visual submodalities. We conclude that deficits of visual perception are far more common after strokes in visual brain areas than is apparent in clinical practice. Our results further clarify the functional organization of midlevel visual cortical areas.

An insect-inspired model for visual binding I: learning objects and their characteristics.

Visual binding is the process of associating the responses of visual interneurons in different visual submodalities all of which are responding to the same object in the visual field. Recently identified neuropils in the insect brain termed optic glomeruli reside just downstream of the optic lobes and have an internal organization that could support visual binding. Working from anatomical similarities between optic and olfactory glomeruli, we have developed a model of visual binding based on common temporal fluctuations among signals of independent visual submodalities. Here we describe and demonstrate a neural network model capable both of refining selectivity of visual information in a given visual submodality, and of associating visual signals produced by different objects in the visual field by developing inhibitory neural synaptic weights representing the visual scene. We also show that this model is consistent with initial physiological data from optic glomeruli. Further, we discuss how this neural network model may be implemented in optic glomeruli at a neuronal level.

The strength of contextual modulation does not correlate across visual sub-modalities

The strength of contextual modulation does not correlate across visual sub-modalities

The strength of contextual modulation does not correlate across visual sub-modalities

The strength of contextual modulation does not correlate across visual sub-modalities

A Vision Architecture Based on Fiber Bundles

Event Abstract Back to Event A Vision Architecture Based on Fiber Bundles Christoph Von Der Malsburg1* 1 Frankfurt Institute for Advanced Studies, Germany We offer a conceptual framework for the construction of an artificial visual system. It serves as basis for the integration of sub-modalities (texture, depth, motion, color, contours, segment markers, illumination, ..) and for autonomous learning. The architecture will decisively reduce the effort necessary to achieve better visual functionality. Visual sub-modalities are conveniently formulated as two-dimensional sheets of neurons with local connectivity. Such sheets can be formalized as manifolds. The points of a sheet carry internal feature spaces of different dimensionality (texture, e.g., may be formalized as a space of Gabor responses, stereo depth, motion and color as 1D, 2D and 3D spaces, respectively), constituting what mathematicians call fiber bundles. Manifolds admit spatial coordinate frames. Different sets of manifolds carry retinal, object-centered or scene-centered coordinate frames. Manifolds are connected by mappings (which in the brain are realized by massive sets of axons). These mappings connect not only coordinate points but also feature spaces. For pairs of manifolds with different coordinate frames mappings are dynamical, that is, they change to keep track of relative motion. Dynamic mappings are governed by local control spaces, which encode relative position and motion. Dynamic mappings thus are themselves fiber bundles. Mappings between fiber bundles implement constraints between their feature values. These constraints connect feature values that refer to the same point in the environment. When looking at a point on the surface of a moving body, for instance, a kinematic constraint connects values for depth and motion of the point, translational and rotatory motion of the body acting as latent parameters. The representation of local surface point motion, in turn, serves to dynamically control the mapping between manifolds with retinal and in object-centered coordinates. Visual input leaves many variables uncertain due to imprecise, ambiguous or absent information. The sub-modality spaces reflect that in terms of more or less broad probability distributions. There is a large number of constraints between different qualities referring to the same point in an image. Many of these constraints are implemented in the mappings between fiber bundles. These mappings typically are forming loops, such that a given variable value is influenced (strengthened or weakened) by several converging mappings. Under the influence of these constraint signals, probability distributions dynamically collapse to delta functions. Thus, the system has contractor dynamics on the short-term level of image interpretation. The system has contractor dynamics also on the long-term level of learning, converging on detailed circuits in a coarse-to-fine manner. Topological mappings between neural sheets have long been shown to be subject to attractor dynamics. Mismatches in constraint loops are repaired by adapting them to each other. Models of recurring patterns are stored by plasticity in horizontal connections. Keywords: architecture, dynamic mappings, Feature spaces, Manifolds, Perception, Subsystem Integration, Vision Conference: Bernstein Conference 2012, Munich, Germany, 12 Sep - 14 Sep, 2012. Presentation Type: Poster Topic: Sensory processing and perception Citation: Von Der Malsburg C (2012). A Vision Architecture Based on Fiber Bundles. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference 2012. doi: 10.3389/conf.fncom.2012.55.00083 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 May 2012; Published Online: 12 Sep 2012. * Correspondence: Dr. Christoph Von Der Malsburg, Frankfurt Institute for Advanced Studies, Frankfurt am Main, Hesse, 60438, Germany, malsburg@fias.uni-frankfurt.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. 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Specificity of fast perceptual learning in shape localisation tasks based on detection versus form discrimination

Perceptual learning is defined as a long-lasting improvement of perception as a result of experience. Here we examined the role of task on fast perceptual learning for shape localisation either in simple detection or based on form discrimination in different visual submodalities, using identical stimulus position and stimulus types for both tasks. Thresholds for each submodality were identified by four-alternative-forced-choice tasks. Fast perceptual learning occurred for shape detection-based on luminance, motion and color differences but not for texture differences. In contradistinction, fast perceptual learning was not evident in shape localisation based on discrimination. Thresholds of all submodalities were stable across days. Fast perceptual learning seems to differ not only between different visual submodalities, but also across different tasks within the same visual submodality.

Two Retinotopic Visual Areas in Human Lateral Occipital Cortex

We describe two visual field maps, lateral occipital areas 1 (LO1) and 2 (LO2), in the human lateral occipital cortex between the dorsal part of visual area V3 and visual area V5/MT+. Each map contained a topographic representation of the contralateral visual hemifield. The eccentricity representations were shared with V1/V2/V3. The polar angle representation in LO1 extended from the lower vertical meridian (at the boundary with dorsal V3) through the horizontal to the upper vertical meridian (at the boundary with LO2). The polar angle representation in LO2 was the mirror-reversal of that in LO1. LO1 and LO2 overlapped with the posterior part of the object-selective lateral occipital complex and the kinetic occipital region (KO). The retinotopy and functional properties of LO1 and LO2 suggest that they correspond to two new human visual areas, which lack exact homologues in macaque visual cortex. The topography, stimulus selectivity, and anatomical location of LO1 and LO2 indicate that they integrate shape information from multiple visual submodalities in retinotopic coordinates.

Adaptive center-surround interactions in human vision revealed during binocular rivalry

We used binocular rivalry as a psychophysical probe to explore center-surround interactions in orientation, motion and color processing. Addition of the surround matching one of the rival targets dramatically altered rivalry dynamics. For all visual sub-modalities tested, predominance of the high-contrast rival target matched to the surround was greatly reduced—a result that disappeared at low contrast. At low contrast, addition of the surround boosted dominance of orientation and motion targets matched to the surround. This contrast-dependent modulation of center-surround interactions seems to be a general property of the visual system and may reflect an adaptive balance between surround suppression and spatial summation.

An explicit and compact coding of geometric and structural image information applied to stereo processing

We introduce a compact coding of image information in terms of local multi-modal image descriptors. This coding allows for an explicit separation of the local image information into different visual sub-modalities: geometric information (orientation) and structural image information (contrast transition and colour). Based on this image representation, we derive a similarity function that compares visual information in each of these sub-modalities. This allows for an investigation of the importance of the different factors for stereo matching on a large data set. From this investigation we conclude that it is the combination of visual modalities that gives the best results. Concrete weights for their relative importance are measured. In addition to these quantitative results, we can demonstrate by our simulations that although our image representation reduces image information by 97% we achieve a matching performance which is comparable to block matching techniques. This shows that our very condensed representation preserves the relevant visual information.

Disruption of space perception due to cortical lesions.

Space control has for a long time been considered a unitary function. The structure associated with this function was the right parietal lobe. Hemispheric specialization for space appeared to make it automatically a human-specific function. However, recent primate research shows different regions of the parietal lobes to be differently involved with space control. A review of the literature, together with own cases shows that there is ample evidence of a modular organization of space control in humans on the basis of specific deficits subsequent to circumscribed cerebral lesions. Lesions influence differentially retinotopic, spatiotopic, egocentric, and allocentric frames of references. They also influence differentially the attention to far or near space, or to global or local features of space. Moreover, preattentive processes can be studied in the neglected hemispace of humans and prove to be sensible to the meaning of visual stimuli. Space representation and attentional mechanisms that seem to operate on these representations are organized in our brain in a very modular fashion, similar to the modularity of visual submodalities. There is probably not a unified space representation in the parietal lobes, but distributed functional modules. Thus, the study of visual optic recognition, either by the brain or by machines, is inconceivable without considering space, attention and awareness.

Relationships between color, shape, and pattern selectivities of neurons in the inferior temporal cortex of the monkey.

1. To examine the way in which information from different visual submodalities is integrated in the inferior temporal (IT) cortex of the monkey, we studied the relationships between the color, shape, and pattern selectivities of individual neurons in IT cortex of two awake macque monkeys. Neurons were recorded while each animal performed a visual fixation task. For each neuron, we analyzed selectivity for the visual submodalities of color, contour shape, and textural pattern using preselected standard sets of visual stimuli, namely colored geometrical shapes with certain patterns. 2. About two thirds (62%) of single neurons whose activities were recorded from the anterior part of IT cortex, which included the ventral bank of the superior temporal sulcus, responded to one or more of the stimuli in the standard sets of stimuli used. An index (stimulus selectivity index) was calculated for each neuron to quantify how well a cell discriminated the preferred stimulus from the least preferred stimulus in each set of stimuli. The stimulus selectivity index, as well as the statistical significance of the variation in the responses to the stimuli within a given set, was used to classify a cell as selective or not selective in a given submodality. Of the neurons whose responses were analyzed quantitatively, 69% were selective for color, 68% were selective for shape, and 82% were selective for pattern. 3. Of the neurons that were tested with respect to the selectivity for color and for shape, 45% were selective both for color and shape, 50% were selective for either color or shape, and only 5% were not selective for color or shape. These frequencies were not significantly different from those predicted from the occurrence of the selective and nonselective neurons in each submodality if the independence of the selectivities for color and shape is assumed. We also found that the color preference of individual neurons does not depend on the shape of the stimulus. These results indicate that there was no overt interaction between the selectivities for color and shape in these IT neurons. 4. Of the neurons that were compared with respect to the selectivity for color and for pattern, 58% were selective both for color and pattern, 38% were selective for either color or pattern, and only 4% were not selective for color or pattern. There was no correlation between the degree of color selectivity and the degree of pattern selectivity of individual neurons.(ABSTRACT TRUNCATED AT 400 WORDS)