Scene variability and perception constancy in the visual system: a model of pre-processing before data analysis and learning

Using a combination of anatomical and physiological techniques we have studied some of the neural connections subserving binocular vision in two species of artiodactyl ungulates (the sheep, Ovis sp., and the goat, Capra hircus). After monocular injections of tritiated proline, transsynaptic transport was observed bilaterally in layers 4 and 6 of visual cortical areas V1 and V2, but there were no sharply defined ocular dominance columns of the kind seen in cats and rhesus monkeys. In coronal sections there was a discontinuity in density of labelling between areas V1 and V2 corresponding to a point in the visuotopic map about azimuth –15° in the ipsilateral visual field. This discontinuity was most pronounced in the hemisphere ipsilateral to the injected eye. We conclude, therefore, that while the cortical representation of ipsilateral visual space can be explained by the retino-geniculo-cortical input pathway from the contralateral eye, the physiologically demonstrated cortical contribution to ipsilateral visual space from the ipsilateral eye cannot be explained in this way. This conclusion was reinforced by experiments using retrograde transport of horseradish peroxidase from the lateral geniculate nucleus (LGN) and medial interlaminar nucleus (MIN) to retinal ganglion cells in flattened whole mounts. These experiments revealed a sharp nasotemporal decussation in the ipsilateral retina, which could not thereby subserve any significant representation of the ipsilateral visual field. In contrast the contralateral nasotemporal decussation was smeared, with many labelled ganglion cells in the temporal retina which could subserve visual input from the ipsilateral hemifield. When we estimated the projection of the nasotemporal decussation line into visual space, we found that it was tilted from vertical by about 5°in each eye, in a similar way to that already reported in the cat. Neurophysiological recordings from binocular neurons in area V1 with different vertical eccentricities also showed that the vertical horopter (the midsagittal reference plane for binocular vision) would be tilted in life when the cyclotorsional position of the eyes was taken into account. Thus both anatomical and physiological methods concur in the prediction that ungulates have a tilted vertical horopter like that described for two other terrestrial species, the burrowing owl and the cat. Anatomical experiments reveal other similarities between the organisation of the ungulate''s visual pathways and that of the cat. For example, after tritiated proline injection in V1, we found visuotopic labelling in the claustrum, dorsal LGN, cortical area V2, and the superior colliculus. Horseradish peroxidase injections in V2 also revealed a direct input to that area from the MIN and dorsal LGN and also from layers 2, 3 and 5 of the splenial area.

1. Luis H. Ospina, MD* 1. *Assistant Professor, Pediatric Ophthalmology and Neuro-ophthalmology, Ste-Justine Hospital, University de Montreal, Montreal, Quebec, Canada After completing this article, readers should be able to: 1. Recognize cortical visual impairment (CVI) as an important cause of pediatric visual loss. 2. Identify the most frequent causes of pediatric CVI and, more specifically, understand the role of hypoxia as a cause of central visual damage. 3. Describe the different patterns and implications for future vision of hypoxic central visual damage occurring in preterm compared with term babies. 4. Know the clinical signs suggestive of CVI in children. 5. Discuss the involvement of visual functions other than visual acuity (ie, cognitive visual aspects) in CVI and correlate them with the likely affected neuroanatomic substrates. 6. Explain the value of using a multidisciplinary approach in rehabilitating children who have CVI early in their development. Vision loss caused by central nervous system damage often is referred to as CVI but also may be referred to as cerebral visual impairment or neurologic visual impairment. These terms refer to the fact that the primary defect may not necessarily be limited to the striate (primary visual) cortex and may affect other areas subserving vision, such as the visual associative cortex, optic radiations, and visual attention pathways. Although it is not yet certain which of these three terms best describes the visual deficit, it is clear that use of the label cortical blindness must be abandoned. That term not only evokes negative connotations for the child and the family but is inaccurate because in almost every instance, some degree of residual vision remains, and visual improvement can occur. CVI has become the greatest cause of pediatric visual impairment in developed countries (1)(2)(3)(4)(5) and is becoming increasingly prevalent in developing nations. CVI is a problem of increasing frequency for two primary reasons. First, the progress in neonatal care has resulted in improved survival of …

BackgroundHow it is possible to “faithfully” represent a three-dimensional stereoscopic scene using Cartesian coordinates on a plane, and how three-dimensional perceptions differ between an actual scene and an image of the same scene are questions that have not yet been explored in depth. They seem like commonplace phenomena, but in fact, they are important and difficult issues for visual information processing, neural computation, physics, psychology, cognitive psychology, and neuroscience.ResultsThe results of this study show that the use of plenoptic (or all-optical) functions and their dual plane parameterizations can not only explain the nature of information processing from the retina to the primary visual cortex and, in particular, the characteristics of the visual pathway’s optical system and its affine transformation, but they can also clarify the reason why the vanishing point and line exist in a visual image. In addition, they can better explain the reasons why a three-dimensional Cartesian coordinate system can be introduced into the two-dimensional plane to express a real three-dimensional scene.Conclusions1. We introduce two different mathematical expressions of the plenoptic functions, Pw and Pv that can describe the objective world. We also analyze the differences between these two functions when describing visual depth perception, that is, the difference between how these two functions obtain the depth information of an external scene.2. The main results include a basic method for introducing a three-dimensional Cartesian coordinate system into a two-dimensional plane to express the depth of a scene, its constraints, and algorithmic implementation. In particular, we include a method to separate the plenoptic function and proceed with the corresponding transformation in the retina and visual cortex.3. We propose that size constancy, the vanishing point, and vanishing line form the basis of visual perception of the outside world, and that the introduction of a three-dimensional Cartesian coordinate system into a two dimensional plane reveals a corresponding mapping between a retinal image and the vanishing point and line.

Visual areas I and II of cerebral cortex of rabbit.

Ideas about retrieval of memories are based largely on localization of function inferred after brain damage. On the other hand, communication in the cerebral cortex occurs through an intricate network of connections, suggesting highly distributed circuits. Loss of memory after lesions thus affects not only the damaged area, but also its rich inputs and outputs. The discussion here is based on a structural model of neural communication that can help explain the process of recruiting highly distributed relevant signals for conceptual and sensory recognition and memory. Discussion of cortical communication has traditionally been sensory-centric, based on the flow of information from the periphery to primary sensory areas and beyond, or in the reverse direction. However, visual signals often do not activate areas along a sequential route as predicted by a hierarchical model, exemplified by the fact that some visual signals activate prefrontal areas earlier than some visual association areas. On the other hand, the structural model for connections is based on the fundamental principle of systematic variation in laminar architecture of the cortex and applies to all cortical systems. The structural model is relational: it predicts that laminar-specific connections in the cortex depend on the structural (laminar) relationship between linked areas. Thus, connections that link an area with simpler laminar structure originate mainly – but not exclusively – in the deep layers and terminate mainly in the upper layers of an area with more elaborate laminar structure. In the opposite direction, connections originate in the upper layers and terminate in the middle-deep layers. Because the laminar architecture across cortical areas is graded, so is the distribution of connections within layers. The structural model holds for connections in all cortical systems and diverse species. Moreover, laminar-specific connections as predicted by the structural model terminate within inhibitory microenvironments that also differ by the distribution of functionally distinct classes of inhibitory neurons that can dynamically shift activity among layers and change cortical rhythms. The relational nature of the structural model and predictions of graded patterns of connections thus suggest that distributed areas and layers are recruited dynamically to meet task demands, including recollection of concepts and events.

In this research we concentrate on adaptive texture feature extractors which are automatically extracted from an image collection. We use independent component analysis (ICA) to extract independent component filters (ICF). ICF have previously been shown to include edge filters, having properties similar to the receptive fields of simple cells of the human visual cortex. In this thesis we evaluate the utility of ICF-based collection-specific features in the context of content-based image retrieval (CBIR), with the view to demonstrate the viability of using such automatic collection-specific features. We find that global features extracted using a small number of ICF outperform those extracted by a bank of Gabor filters, even when very large number of Gabors are used. We also present comparisons against a variety of state-of-the-art features and show that ICF-based features perform better than these, without the need for any hand-tuning. ICA extracts large number of filters. In order to find a useful smaller subset we evaluate a previously-published variance-based filter selection method. We identify the shortcomings of this method. Our proposed improvements to filter-based feature selection and extraction, response scaling and locally normalised convolution, was a result of trying to address some of these shortcomings. Even with these improvements the variance-based method has an intrinsic flaw of being susceptible to selecting redundant filters. We propose a new filter selection method based on normalised cross-correlation and clustering. We show that our method selects a more useful subset compared to the previously published variance-based method. We also propose a salient-point based local feature which uses ICF and show that our proposed feature performs better than SIFT features and also the global ICF features. We further illustrate the utility of ICFSIFT by developing a grid-based adaptive local feature and we demonstrate that ICFSIFT extracts different and useful information compared to the ICF-based global and grid-based local features. After applying the techniques proposed in this thesis to four standard texture collections, we show that, while hand-tuned features can work well for their target collection, the automatic adaptive features perform better for the general case.

Objective To research the recovery of the visual cortical function mediating visual motion perception in ametropic amblyopia after regular amblyopia treatment using 3.0 Tesla functional MRI (fMRI).Methods In this prospective study,blocks-designed fMRI experiment was performed on nine children with first was diagnosed as ametropic amblyopia,and review fMRI after one week,two weeks and one month.During the study,the patients were asked to view stimuli through rotating the checkerboard,which contrast ratio approach to 100％ and frequency approach to 8 Hz,Functional MRI data were processed by using SPM8 which based on the Matlab 7.12.The matrix data of each treatment stage were acquired bv hypothesisdriven research,and before and after self-control study (matched t-test) was performed in each group to acquire average cerebral cortex activated functional images data.The different mapping between each group during visual motion stimulus was also acquired.Results The functional area that is bilateral occipital lobe (Mean t of the right BA18=1.236 1 ;Mean t of the left BA18=1.521 1; Mean t of the right BA19=1.6845; Mean t of the left BA19=1.591 7,P＜0.005) and the visual association area (V5) (The right BA37 was activated and Mean T=1.201 4;The right BA21 was activated and Mean t=1.145 0,P＜0.005) expanded in different levels after amblyopia treatment two weeks; After four weeks,the bilateral occipital lobe (Mean t of the right BA18=1.0024; Mean t of the left BA18=1.743 1; Mean t of the right BA19=1.2253; Mean t of the left BA19=1.181 3,P＜0.005) showed activation on the small area compare with two weeks ago.Conclusion In the early functional training of the older children's ametropic amblyopia,reconstruction the visual cortical function mediating visual motion perception was more difficulty and unstable. Key words: Children ; Amblyopia; Cerebral cortex ; Magnetic resonance imaging

Background The formation of amblyopia is closely associated with glutamate receptors of visual cortex, and researches determined that the expression of metabolic glutamate receptor 1 (mGluR1) in the visual cortex of amblyopic rats is down-regulated.However, the effect of mGluR1 on synaptic transmission of neurons in the visual cortex is unclear. Objective This study was to investigate the role of mGluR1 in the synaptic transmission efficiency of neurons in the primary visual cortex of monocular form-deprivated rats. Methods Sixteen 14-day-old SD rats were randomly divided into normal control group and form-deprivation group, with 8 rats in each group.The eyelids of the left eyes were sutured to establish the monocular form-deprivation models in the rats of the form-deprivation group, and the visual cortex slices were prepared until 31 days after modeling and incubated in artificial cerebrospinal fluid with 3, 5-dihydroxyphenylglycine (DHPG), LY367385+ DHPG, 2-methyl-6-(phenyl acetylene) pyridine hydrochloride(MPEP)+ DHPG and LY367385+ MPEP+ DHPG, respectively.The field excitatory postsynaptic potential (fEPSP) of neurons in the visual cortex of V1 area was detected by extracellular microelectrode recording.The use and care of the animals followed the statement for the Use of Animals in Ophthalmic and Vision Research. Results The slope value before drug treatment was set as 100%, the fEPSP-slopes of the normal control group and the form-deprivation group were increased to (136.4±17.3)% and (120.7±12.8)% after DHPG induction with significant difference between the two groups (t=2.280; P<0.05). The fEPSP-slopes of the normal control group were (114.9±9.3)% and (112.6±15.3)% after LY367385 and MPEP treatment, and those of the form-deprivation group were (107.3±6.0)% and (110.1±4.1)%, which were significantly lower than those after DHPG induction (normal control group: t=2.641, 2.915; both at P<0.05; form-deprivation group: t=2.410, 2.372; both at P<0.05). The fEPSP-slopes of the normal control group and the form-deprivation group were (104.5±2.2)% and (102.8±14.9)% after LY367385+ MPEP treatment, which were lower than that after DHPG induction (t=3.080, 2.306; both at P<0.05). Conclusions The effect of mGluR1 on the synaptic transmission of neurons in the visual cortex weakens after monocular form-deprivation in rats.Both mGluR1 and mGluR5 participate in the neuronic synaptic transmission on visual cortex area and appear to be equivalent contribution. Key words: Electrophysiology; Excitatory amino acid agonists/pharmacology; Excitatory amino acid antagonists/pharmacology; Phenylacetates/pharmacology; Receptors, metabotropic glutamate/physiology; Visual cortex/growth & development; Neuronic synaptic transmission/drug effect; Form deprivation; Rats, SD

Background Chondroitin sulphate proteoglycans (CSPGs) can cause the termination of ocular dominance plasticity in the visual cortex.Recently,protein tyrosine phosphatase σ (PTPσ) has been identified as a receptor that inhibits CSPGs.However,whether PTPσ and its downstream molecules participate in the reactivation of ocular dominance plasticity in adult visual cortex has not been studied.Objective The present study was to investigate the changes in the expression of the PTPσ,probabilistic neural networks (PNNs),and molecules downstream of PNN,such as N-cadherin/β-catenin,after the reactivation of adult visual cortical plasticity.Methods Fifty-four SPF Long Evans rats were grouped according to different postnatal week (PW) as the PW1 (6 rats),PW3 (6 rats),PW5 (6 rats),PW7 (24 rats),and PW9 (12 rats) groups,and the upper and lower eyelids were sutured in the 12 rats from the PW7 group for 14 days to establish the binocular plasticity reactivation models.Expression of PTPσ and PNNs in the rat visual cortex was detected using immunochemistry,and changes of PTPσ mRNA,N-cadherin mRNA and β-catenin mRNA expression in the rat visual cortex with plasticity reactivation were assessed by real-time fluorescence quantitative PCR (RT Q-PCR).The use of animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results The expression level of PTPσ mRNA was significantly higher in the PW9 group than that of the binocular plasticity reactivation models and the PW7 group (t =1.965,3.526,P＜0.01).The staining of the rat visual cortex for PTPσwas localized to the cellular membrane,cytoplasm and axon.Cell densities of the PW9 group in the Ⅱ-Ⅲ layer,Ⅳ layer and Ⅴ-Ⅵ layer of the visual cortex were elevated in the PW9 rats compared with the PW7 rats (t =24.593,23.444,13.556,P＜0.01) and rats from the binocular plasticity reactivation model (t =44.111,43.000,16.556,P＜0.01).Cell densities for PNNs in the Ⅳ and Ⅴ-Ⅵ layers were significantly increased in the PW9 rats in comparison with the PW7 rats (t=1.926,P＜0.01 ;t=1.370,P＜0.05),but the cell density in the Ⅱ-Ⅱ layer has no statistical significance (t=0.889,P＞0.05).However,cell densities for PNNs in the Ⅱ-Ⅲ and Ⅳ layers in the binocular plasticity reactivation models were lower than those of the PW9 rats (t =2.556,4.585,P＜0.01).Compared with PW1 rats,the expression levels of the N-cadherin mRNA in the PW3,PW5,PW7,PW9 rats were lower (t =28.932,28.988,27.083,28.908,P＜0.01),but those in the PW7 rats were enhanced in comparison with the PW3 rats,PW5 rats and PW9 rats (t =1.848,1.904,1.825,P＜0.01).No significant difference was seen in the expression of the N-cadherin mRNA between the PW9 rats and rats from the binocular plasticity reactivation model (t =0.072,P＞0.05).A statistically significant increase was found in the β-catenin mRNA expression in the PW1 rats compared with the PW3,PW5,PW7 and PW9 rats (t =3.918,3.534,2.645,4.652,P＜ 0.0 1),as well as between rats from the binocular plasticity reactivation model and the PW9 rats (t =0.570,P＜0.01).Conclusions PTPr,PNNs and β-catenin are involved in the reactivation of ocular dominance plasticity in the adult visual cortex. Key words: Visual cortex; Protein tyrosine phosphatase σ; Plasticity; Binocular form-deprivation

Objective: To investigate the effect of caloric restriction on the plasticity of the visual cortex in monocular-deprived adult amblyopic mice, and to explore possible molecular mechanisms. Methods: This was an experimental study. A total of 54 neonatal healthy Kunming mice were randomly divided into 3 groups: a control group (n=18), a monocular deprivation+ad libitum (MD+AL) group (n=18), and a monocular deprivation+caloric restriction (MD+CR) group (n=18). MD model of mice was established at postpartum 21 days, and deprivation factors were removed at postpartum 35 days. At their postpartum 63 days, visual acuity and electrophysiological tests were used to detect visual function changes, and the expression levels of the proteins involved in plasticity in the visual cortex (postsynaptic density 95, PSD95; synaptophysin, SYP; growth-associated protein 43, GAP-43) were measured by immunohistochemistry and Western Blot. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression level of the insulin-like growth factor-1 (IGF-1). Two-way repeated measurement analysis was used to compare data from each group. Results: The final numbers for the control group, MD+AL group and MD+CR group were 14, 18 and 18 mice, respectively. The percentage of weight increase in the MD+CR mice was significantly lower than the percent increase in the MD+AL group (P<0.05) from the beginning of the first week. The visual acuity of the MD+AL group was significantly lower than the acuity in both the control and MD+CR groups (P<0.05). The expression levels of the three synaptic-associated proteins (PSD95, SYP, GAP-43) in the MD+AL group were all lower than levels in the control and MD+CR groups. RT-PCR showed the level of IGF-1 mRNA in the MD+AL group was significantly lower than the level in the control and MD+CR groups (P<0.05), but increased significantly in the MD+CR group (P<0.05). Conclusions: CR can improve the visual function of adult MD mice, increase the expression of synapse-related proteins in the visual cortex, and reactivate the plasticity of the adult visual cortex. Further research shows IGF-1 may be involved in regulating these effects. Key words: caloric restriction; form deprivation; amblyopia; visual function; mice

The result of a cognitive process, a symbol is a type of channel for visual communication. For complicated thinking behaviors, designers concretize and visualize abstract concepts. Visual design is one of the major elements in the formation and construction of meaning. Cognition is the key to constructing the communication of a message (symbolic design). For visual designers, communication and the visual cognition thereof are the ultimate goals. Designers need not only seek unique expression of visual beauty but also achieve an organic goal in visual communication, wherein, as a result, symbolic communication and cognition are required to reduce the cognitive noise in the process. The Swiss linguist Saussure has stated that ”symbols are combined with the signifier and the signified” to explain that symbols consist of the combination of formation and concept. He also discussed an arbitrary concept of symbols to illustrate the interaction between meanings and formation. By using concrete surface features transferred to abstract meaning to design cognitive procedures for symbolic design, an operational model of symbolic and cognitive design is explored. The purpose of this study was to understand the cognition and transference utilized by designers in the process of symbolic formation of meanings. On the basis of semiotics and cognitive psychology, a set of systemized-design operational methods was arranged and a study of designers' ”meaning” and ”formation” in symbolic design applied to the basic structure of visual cognition. The basic structure of both visual cognition and the creation of visual design procedures was used to explore the structural relationships among visual symbol formation, meanings and cognition.

In everyday life whenever people observe, interact or speak to each other, visual attention is mostly directed toward the other person’s face, particularly to the eyes and the nearby periocular regions. This is naturally reflected when the user interacts with their mobile phones in several usual activities, such as web access, payments and video calls. For this reason, the functionality of mobile devices is strongly affected by the design of the user interface. In this chapter, we propose a biologically inspired approach for continuous user authentication based on the analysis of the ocular regions. The proposed system is based on a modified version of the HMAX visual processing module. HMAX is a hierarchical model which has been conceived to mimic the basic neural architecture of the ventral stream of the visual cortex. The original HMAX model consists of four layers: S1, C1, S2 and C2. S1 and C1 represent the responses to a bank of orientation-selective Gabor filters. S2 and C2 represent the responses of simple and complex cells to other textural features. The discrimination power of HMAX in recognizing classes of objects is invariant to rotation and scale. The C1 layer, which is mainly responsible for the scale and rotation invariance, is implemented using a max-pooling operation, which may lose some spatial information. To overcome this problem while preserving the maximal visual acuity and hence the localization accuracy, we propose to augment the model by applying a retinal log-polar mapping. The log-polar mapping is an approximation of the retino-cortical mapping that is performed by the early stages of the primate visual system. Due to the high density of the cones in the fovea, the log-polar approximation of the space-variant distribution model of the photoreceptors can only be applied outside the foveal region. Therefore, the log-polar mapping is added to the HMAX model as a complementary stage to process the peripheral region of the grabbed images. In order to demonstrate the feasibility of the proposed approach to mobile scenarios, experimental results obtained from publicly available databases and image streams grabbed from mobile devices will be presented.

In this thesis I aim to address the different components of visually driven goal-directed behavior, to understand how the brain can “keep an eye on the prize”. I use the mouse as a model system for the following reasons: 1) the main components of the mouse and human brain are similar, 2) we can make use of genetic tools in order to disentangle circuits involved in goal-directed behavior more specifically, and 3) the small size of the mouse brain makes it easier to visualize many cortical areas simultaneously, which is especially an advantage in tasks involving sensory input (posterior areas) as well as motor action (frontal areas). In Chapter 1 I introduce the (mouse) visual system and the concept that visual perception is modulated by context. I also introduce working memory as persistent activity during a delay, and how this is likely an emergent property of distributed functional networks. In addition, I explain how the basal ganglia are ideally suited to take up an orchestrating role as part of these functional networks. In Chapter 2 ”Mouse visual cortex contains a region of enhanced spatial resolution”, my colleagues and I reveal that despite the absence of a fovea in the retina, aspects of the organization of the visual cortex of mice resemble the foveal organization seen in primate visual cortex. We describe a region with enhanced spatial resolution in the visual cortex (‘focea’) which is behaviorally relevant: the mouse can see sharper with the focea. These findings have important implications for using the mouse as a model for human visual perception. In Chapter 3 “The essential role of recurrent processing for figure-ground perception in mice”, we find evidence that feedback signals from higher to lower visual areas are important to provide the visual context to cells with smaller receptive fields. This is useful, for example, for segregating a figure from a similar background. When this feedback signal is disturbed, both the neural correlate for separating figures from a background in the brain as well as figure detection performance decrease. In Chapter 4 "The direct and indirect pathways of the basal ganglia antagonistically influence cortical activity and perceptual decisions”, we first confirm that the two pathways of the basal ganglia can antagonistically bias motor responses and cortical activity in a visual detection task. We then demonstrate in a similar task with a delay between the sensory input and motor action that the basal ganglia also antagonistically bias the working memory of visual input and motor actions in the future. In the same task, we also observe interesting neuronal correlates of task parameters after a trial has finished. From computational models we know that these correlates, known as eligibility traces, are important for learning: they can be used to assign credit (or blame) after an outcome. Hence, we decided to investigate these possible eligibility traces further in Chapter 5 “Post-trial representations of task events throughout the dorsal cortex are modulated by behavioral context”. Altogether, this thesis adds relevant and new information to the process of visually driven goal-directed behavior. I propose that the cortex functions like an orchestra, with the basal ganglia as its conductor. New developments in systems neuroscience will enable large-scale recordings of individual neurons and neurotransmitters to further decipher if this is indeed how the brain manages to behave in a goal-directed way and keep an eye on the prize.

Chapter 7 - The striate cortex and hemianopia

Understanding driver's characteristic of visual activity is important process because driver depends on a visual signal more than 90% for getting outside information needed to drive, thus a series of driving, including perception, judgement, and activity, is completed. This study analyzes quantified driver's sight range in curved section where recognition of various information is critical due to biggest speed change among sections. Simulation is utilized for this study because of safety problem on field experiment and difficulties in using equipment. Building 6 roads that have different in curve radius by virtual driving map, experiment is carried out recruiting 30 people. Through analytical researches, it shows that drivers keep an eye on direction of driving, and driver's visual range is narrowed on left curve than right curve, and the more curve radius become small, the more drivers see in narrow angle.