Visual Organization Research Articles

Study of visual pigment rhodopsin supramolecular organization in photoreceptor membrane by small-angle neutron scattering method with contrast variation.

Supramolecular organization of rhodopsin in the photoreceptor membrane was investigated by small-angle neutron scattering method. The experiments, which were performed with mixtures of heavy/light water as solvent (contrast variation method), were aimed at obtaining information about the lipid and protein components of the photoreceptor disc membrane separately. It was shown that the packaging density of the rhodopsin molecules in the photoreceptor membrane was unusually high: the distance between the centers of the molecules was approximately 56 Å. The probability of the monomeric state of rhodopsin molecules in the photoreceptor membrane, according to the data obtained, is rather high.

Cognitive effects of deep brain stimulation in patients with obsessive-compulsive disorder.

Deep brain stimulation (DBS) is a promising treatment for treatment-refractory obsessive-compulsive disorder (OCD). However, the effects of DBS on cognitive functioning remain unclear. Therefore, we aimed to assess cognitive safety of DBS for treatment-refractory OCD and the association between clinical changes and cognitive functioning. Patients with treatment-refractory OCD treated with DBS targeted at the nucleus accumbens (NAcc) were compared with a control group of 14 patients with treatment-refractory OCD treated with care as usual. We assessed cognitive functioning at baseline, 3 weeks postoperatively and following 8 months of DBS. We compared change in clinical symptoms with cognitive changes. There were 16 patients in the DBS group and 14 patients in the control group. Three weeks postoperatively, the DBS group showed a significantly reduced performance on measures of visual organization and verbal fluency and a trend toward reduced performance on measures of visual memory and abstract reasoning. Cognitive functioning was found to be stable on all other measures. After 8 months of DBS, reduced performances persisted, except for a significant improvement in verbal fluency. Cognitive functioning in all other domains remained unaffected. We found no correlation between improvement of clinical symptoms and cognitive changes. A limitation of this study was its relatively small sample size. Deep brain stimulation targeted at the NAcc may be considered a safe method in terms of cognition because cognitive functioning was unaffected on most neuropsychological measures. Nevertheless, we observed some minor reduced performance on specific measures of executive functioning that were possibly associated with surgical intervention. Our results suggest that severity of OCD symptoms is independent of cognitive functioning.

Perceptual organization deficits in traumatic brain injury patients

Traumatic brain injury (TBI) is a prevalent condition and there is limited visual perception research with this population. Here, we investigated perceptual organization changes in a rather homogeneous sample of closed head TBI outpatients with diffuse axonal injury only and no other known comorbidities. Patients had normal or corrected visual acuity. Perceptual organization was measured with the Leuven Perceptual Organization Screening Test (L-POST), a coherent motion task (CM) and the Leuven Embedded Figures Test (L-EFT). These tests were chosen to screen for deficits in different aspects of perceptual organization (L-POST), to evaluate local and global processing (L-EFT) and grouping in a dynamic set of stimuli (CM). TBI patients were significantly impaired compared to controls in all measures for both response time and accuracy, except for CM thresholds and object recognition subtests. The TBI group was similarly affected in all aspects of the L-EFT. TBI was also similarly affected in all perceptual factors of the L-POST. No significant correlations were found between scores and time post-injury, except for CM thresholds (rs=−0.74), which might explain the lack of group-level differences. The only score significantly correlated to IQ was L-EFT response time (rs=−0.67). These findings demonstrate that perceptual organization is diffusely affected in TBI and this effect has no substantial correlations with IQ. As many of the neuropsychological tests used to measure different cognitive functions involve some level of visual discrimination and perceptual organization demands, these results must be taken into account in the general neuropsychological evaluation of TBI patients.

Experience of Visual Perception in the Design Education

Relevance of the paper is due to theoretical and practical necessity to study the peculiarities of design education. Modern designer shall, theoretically and methodologically, master the system of design engineering based on the laws affecting the form of product, methods of styling design and design quality analysis, basics of materials science and industrial design engineering. Design of industrial products shall draw upon historical, cultural, logistical, aesthetic and artistic foundations. The paper applies methods of cultural and historical analysis, comparative methods, methods of analysis and simulation of semiotic systems.Authors, emphasizing training process integrity for design specialists, pay attention to the fact that in the modern urban world requirements to visual aesthetics are particularly important, ensuring videoecology of objects and environment, creating maximum emotional comfort. Ability to create emotional environment is due to form quality, generating peculiarities of psychological reactions as emotions. The study of form perception revealed the mechanism of creating emotional response associated with semantic capacity of design object and special features of its visual organization. Perception model of visual images in design was suggested, including recognition, comparison and dialogue processes. The findings are scientifically-based recommendations, tailored to visual perception and aimed at creating emotional comfort in design.

Visual-motor embodiment of language: a few implications for the neuropsychological evaluation (in Alzheimer's disease).

For several decades, researchers in cognitive neuroscience and cognitive psychology have developed works concerning the close relationships between “lower-level” perceptual/motor and “higher-level” conceptual/linguistic processes (Harnad, 1987; Goldstone, 1994; Barsalou, 1999; Pulvermuller and Fadiga, 2010). Some of them suggested to “reunit” perception and conception (Goldstone and Barsalou, 1998), studied the interactions between language and action (Glenberg and Kaschak, 2002; see Pulvermuller and Fadiga, 2010, for a global picture in neuroscience), or were interested in the relationships between language and other bodily (emotional) states (Glenberg et al., 2005). On the neurophysiological and ophthalmological grounds, contemporary studies suggest that not only does Alzheimer's Disease (AD) lead to alteration in brain cortical structure and cognitive impairment, but it also conducts to deep changes in both visual system organization and vision-based performances (Tzekov and Mullan, 2013). We recommend that both the perceptual impairment found in AD and the interactions between lower-level and higher-level cognition be taken into account by neurospychologists in order to avoid misattribution of performance deficits. We first mention a recent research concerning language evaluation in AD and discuss main limitations of modular evaluation in that type of context. Then, we present main features of the visual “function” impairment in AD, the impacts of perceptual changes over higher-level cognition, and finally, we provide general recommendations for neuropsychological testing of higher-level cognitive “functions”. Linguistic evaluation in AD Drummond et al. (2015) reported an interesting research in which language production processes were evaluated in patients with AD, amnestic mild cognitive impairment (a-MCI), and controls. In contrast with many neuropsychological tests aiming at evaluating language on the basis of simple concept production (e.g., naming), the authors developed a “narrative test,” in which participants were supposed to narrate a story from a sequence of visually presented actions. Overall, the authors found that patients with a-MCI already presented narrative deficits in comparison with the control group. Interestingly, a-MCI discursive deficits were lower than those presented by patients with AD, which may be interpreted as an intermediate level of deficiency between healthy elderly and patients with AD. The research is interesting and allows us to examine usual practices in neuropsychology and neuropsychological research. Although the participants in this kind of research generally undergo both neuropsychological and visual (i.e., acuity) assessments, the real involvement of language “function” in the deficits found in patients with AD or a-MCI can be questioned. As we will see later, AD can lead to several visual processing impairments that influence higher-level cognitive performance so that checking for normal or corrected-to-normal visual acuity is not sufficient to control for lower-level influence on cognitive performance. Typically, whether in neuropsychology or in speech therapy, language abilities in AD are often evaluated by tests involving the visual “function”. For instance, in the naming tests, patients have to orally produce the word represented by a drawing picture. Similarly, oral comprehension tests ask patients to indicate, among several pictures, which corresponds to a word or a sentence read by the examiner. In other words, patients have to visually recognize a picture (as in the naming tests) based on an oral description. The matching category tests also require patients to choose—among several visual items—the one that is semantically associated with a target item. Finally, tests that focus on graphic abilities (e.g., dictation, free writing, writing description) also rely on visual “functions”. When performances are altered in the tests such as those described above, any earlier level of information processing can be involved (Greene, 2005). Although they are mainly employed to evaluate language, these tests can also reflect visual “function” impairment. The semantic recognition of drawings or pictures implies that patients rely on good visual acuity, color vision, contrast sensitivity, and oculomotor processing. Misinterpretations of AD patient troubles may arise if visual performances are not taken into account (and controlled for in statistical analyses).

The relationship between cognition, job complexity, and employment duration in first-episode psychosis.

To investigate the relationship between cognition and employment duration in first-episode psychosis (FEP), and establish if a "fit" between cognition and job complexity is associated with longer employment duration. This study involved secondary data analysis of a subsample of FEP individuals (n = 65) who participated in a randomized controlled trial comparing Individual Placement and Support plus treatment as usual (TAU), versus TAU alone, over 6 months. A cognitive battery was administered at baseline and employment duration (hours) and job complexity in the longest held job over 6 months were measured. Factor analysis with promax rotation of the cognitive battery revealed 4 cognitive domains: (a) attention and processing speed; (b) verbal learning and memory; (c) verbal comprehension and fluency; and (d) visual organization and memory (VO&M). The final hierarchical regression model found that VO&M and job complexity independently predicted employment duration in longest held job; however, the "fit" (or interaction) between VO&M and job complexity was not significant. These findings suggest that VO&M and job complexity are important predictors of employment duration, but it is not necessary to ensure VO&M ability matches job complexity. However, there are limited comparative studies in this area, and other aspects of the person-organization fit perspective may still be useful to optimize vocational outcomes in FEP.

Midlife Hypertension Risk and Cognition in the Non-Demented Oldest Old: Framingham Heart Study.

Midlife cardiovascular risk, hypertension (HTN) in particular, has been related cross-sectionally to poorer neuropsychological (NP) performance in middle age and older adults. This study investigated whether a similar relationship persists between midlife HTN or systolic blood pressure (SBP) and NP performance approximately 30 years later. 378 Framingham stroke and dementia-free Original cohort participants, with HTN and SBP ascertained between 50-60 years of age (mean age 55 ± 1, 65% women), were administered a NP assessment at age ≥80 years. Tests included Logical Memory, Visual Reproduction, Paired Associate, Hooper Visual Organization Test, Trail Making A & B, Digit Span Forward and Backward, Controlled Word Association Test (COWAT), and Similarities. Multivariable linear regression, adjusted for age, time interval between risk factor and NP testing, gender, and premorbid intelligence, assessed association between midlife HTN/SBP and NP outcomes. Midlife HTN was not significantly associated with NP outcome measures. Midlife SBP was associated with poorer Digit Span Forward and COWAT performance (p < 0.05). No significant interaction of age on HTN/SBP to NP associations was found. There was a significant interaction between ApoE4 status and SBP in their effects on COWAT (pinteraction = 0.074); SBP was negatively associated with COWAT only in those with the ApoE4 allele (p = 0.025). While midlife HTN is not associated with late life cognitive impairment, midlife SBP is related to late life attention and verbal fluency impairments, particularly among ApoE4+ individuals. These results offer insight into processes that are operative in the absence of overt cognitive impairment and dementia.

Appropriating the Mola: Forms of Borrowing by Textile Artists

Mola panels, made of layers of cloth, are a well-known souvenir and collectible internationally. A pair of rectangular mola panels form the back and front of a mola blouse and are part of the dress of an indigenous American Indian people, the Kuna (Guna), who live in Panama and Colombia. While the mola may be considered a form of wearable art, it has become a source of inspiration for contemporary Western textile artworks. The techniques used by Kuna women to sew mola panels – surface appliqué, reverse appliqué and embroidery – have been imitated, adapted, and transformed by textile artists, often as an evolving practice. The global influence of the mola is demonstrated in case studies of the work of six textile artists: Tsuyako Miyazaki (Japan), Fumiko Nakayama (Japan), John Corbett (Australia), Charlotte Patera (US), Christel Walter (Germany) and Herta Puls (UK). The works reviewed, stitched from the 1970s until recent times, are considered in terms of visual organization, color palette, materials, design motif, scale, sewing techniques, intent (meaning to the maker) and display qualities. The individual strategies of artists in responding to sources of inspiration originating from non-western cultures are considered along a continuum from imitation, through adaptation, to transformation.

Book Review: “The Low Visibility of Low Vision: Increasing Awareness through Public Health Education

Low Visibility of Low Vision: Increasing Awareness through Public Health Education, by Rosemary Janiszewski, Shelly L. Heath-Watson, Adrienne Y. Semidey, Arlen M. Rosenthal, and Quynh Do, published in the 2006 Special Supplement of the Journal of Visual Impairment & Blindness, Volume 100, pp. 849-861. As the director of the Professional Preparation Program in Vision Rehabilitation Therapy at Salus University and a practicing certified vision rehabilitation therapist, I am responsible for educating and training students, colleagues, consumers, families, and the community about the critical role vision rehabilitation therapists retain throughout the entire vision rehabilitation process. Consequently, I consider advocacy to be an integral component of my professional ethics and practice. Over time, however, my advocacy pursuits have led me to conclude that the vision rehabilitation therapy profession, and other vision rehabilitation professions (low vision therapy and orientation and mobility), are not well known to many of the eye care professionals, consumers, and communities we have been trained to consult and serve. Thus, the continuum of care provided to those individuals with visual impairments (that is, blindness or low vision) falls short. It has been reported that the prevalence of visual impairment is expected to increase as the population lives longer (World Health Organization, n.d.); however, despite valuable global actions to prevent visual impairment, such as the Vision 2020 initiative launched by the World Health Organization and the International Agency on Preventing Blindness, there remains a need for vision rehabilitation intervention when sight-saving measures do not prevail. It is at this juncture in the continuum of care in which individuals experiencing vision loss should be referred to vision rehabilitation therapists and other vision rehabilitation professionals for treatment and training to restore independence and safety. In my role as an educator and advocate for vision rehabilitation therapy, I search for literature and research materials that support the theory, practice, and relevancy of vision rehabilitation service delivery. In that search, I discovered a JVIB article entitled, Low Visibility of Low Vision: Increasing Awareness through Public Health Education, and I was immediately intrigued by the article's emphasis on the need for a health education program to increase awareness of low vision, a that would correspond to professional practice in vision rehabilitation therapy. The article discussed in detail the components of an effective public health education to increase the awareness of low vision by: identifying the intended audience and formulating an appropriate communication strategy to disseminate the message, pre-testing the communication strategy with the intended audience (that is, use of focus groups); implementing the strategy by collaborating with visual impairment organizations and creating educational materials, exhibits, and programs that further convey the message; and, finally, assessing and evaluating the effectiveness of the communication strategy and identifying refinements where needed. This article spoke directly to one of the major challenges facing the profession of vision rehabilitation therapy today: lack of professional identity and awareness of vision rehabilitation therapy among eye care professionals, people with vision loss, and other members of the rehabilitation team. In April 2014, Salus University and Vision-Serve Alliance convened the Vision Rehabilitation Therapy, Strategic Planning, and Advisory Symposium to address these challenges. Participants included representatives from professional preparation programs, state vocational rehabilitation agencies, the Academy for Certification of Vision Rehabilitation and Education Professionals, consumer groups, and the Veterans Administration. …

Comparison of visual perceptual organization in schizophrenia and body dysmorphic disorder

People with schizophrenia are impaired at organizing potentially ambiguous visual information into well-formed shape and object representations. This perceptual organization (PO) impairment has not been found in other psychiatric disorders. However, recent data on body dysmorphic disorder (BDD), suggest that BDD may also be characterized by reduced PO. Similarities between these groups could have implications for understanding the RDoC dimension of visual perception in psychopathology, and for modeling symptom formation across these two conditions. We compared patients with SCZ (n=24) to those with BDD (n=20), as well as control groups of obsessive–compulsive disorder (OCD) patients (n=20) and healthy controls (n=20), on two measures of PO that have been reliably associated with schizophrenia-related performance impairment. On both the contour integration and Ebbinghaus illusion tests, only the SCZ group demonstrated abnormal performance relative to controls; the BDD group performed similarly to the OCD and CON groups. In addition, on both tasks, the SCZ group performed more abnormally than the BDD group. Overall, these data suggest that PO reductions observed in SCZ are not present in BDD. Visual processing impairments in BDD may arise instead from other perceptual disturbances or attentional biases related to emotional factors.

Indeterminacy tolerance as a basis of hemispheric asymmetry within prefrontal cortex.

There is an important hemispheric distinction in the functional organization of prefrontal cortex (PFC) that has not been fully recognized and explored. Research with split-brain patients provides considerable evidence for a left hemisphere (LH) “interpreter” that abhors indeterminacy and automatically draws inferences to complete patterns (real or imaginary). It is suggested that this “interpreter” function may be a byproduct of the linguistic capabilities of the LH. This same literature initially limited the role of the right hemisphere (RH) to little more than visual organization. Recent reviews have garnered evidence for several different roles for the right PFC in reasoning, problem solving, and decision-making. We here focus on the beneficial but neglected role of indeterminacy in real-world problem solving and argue that the right PFC complements the left PFC “interpreter” by maintaining, and even enhancing indeterminacy. Successful real-world functioning is a delicate balancing act between these two systems.

Material properties from contours: New insights on object perception

In this work we explored phenomenologically the visual complexity of the material attributes on the basis of the contours that define the boundaries of a visual object. The starting point is the rich and pioneering work done by Gestalt psychologists and, more in detail, by Rubin, who first demonstrated that contours contain most of the information related to object perception, like the shape, the color and the depth. In fact, by investigating simple conditions like those used by Gestalt psychologists, mostly consisting of contours only, we demonstrated that the phenomenal complexity of the material attributes emerges through appropriate manipulation of the contours. A phenomenological approach, analogous to the one used by Gestalt psychologists, was used to answer the following questions. What are contours? Which attributes can be phenomenally defined by contours? Are material properties determined only by contours? What is the visual syntactic organization of object attributes? The results of this work support the idea of a visual syntactic organization as a new kind of object formation process useful to understand the language of vision that creates well-formed attribute organizations. The syntax of visual attributes can be considered as a new way to investigate the modular coding and, more generally, the binding among attributes, i.e., the issue of how the brain represents the pairing of shape and material properties.

Two Types of Visual Objects

Abstract While it is widely accepted that human vision represents objects, it is less clear which of the various philosophical notions of ‘object’ adequately characterizes visual objects. In this paper, I show that within contemporary cognitive psychology visual objects are characterized in two distinct, incompatible ways. On the one hand, models of visual organization describe visual objects in terms of combinations of features, in accordance with the philosophical bundle theories of objects. However, models of visual persistence apply a notion of visual objects that is more similar to that endorsed in philosophical substratum theories. Here I discuss arguments that might show either that only one of the above notions of visual objects is adequate in the context of human vision, or that the category of visual objects is not uniform and contains entities properly characterized by different philosophical conceptions.

A bio-inspired center-surround model for salience computation in images

A center-surround model inspired by photoreceptor interactions and visual receptive field organization is presented in this paper for salience computation that predicts human eye fixation locations in images. The essence of photoreceptor interactions is implemented considering different nonlinear combinations of responses to stimuli given by values at nearby image pixels. These combinations are then fed to difference of Gaussian filtered outputs operation and Gabor filter based processes simulating visual receptive field organization. The proposed center-surround model is used in Itti et al.’s bio-inspired framework to perform salience computation. Analysis is carried out to present the information-theoretic aspect of the nonlinear combinations. Significance of the proposed center-surround model is shown both qualitatively and quantitatively by comparing its use in salience computation with the use of existing models considering different psychological patterns, and synthetic and real-life images. Quantitative and qualitative performance of salience computation using the novel center-surround model for three well-known datasets of images are also compared to that of relevant existing salience computation approaches to demonstrate the effectiveness of the proposed approach in generating salience maps closer to human eye fixation density maps.

OP39 – 2489: Improving the fundamentals of learning: Cognitive neurorehabilitation for children with partial epilepsy

Objective Attention and visuospatial impairments occur in children with partial epilepsy (PE). Attention impairment interrupts the development of other cognitive functions, eg. working memory and executive functions. Visuospatial impairment for one has been associated with difficulties in mathematics. Few systematically controlled neurocognitive rehabilitation techniques for children exist. Our aim was to examine the intervention effect with a computer-based attention and visuospatial rehabilitation modules for children. Methods 27 children with PE: 16 in study group (mean age=10.07 yrs, SD=1.149) and 11 in waiting-list group (mean age = 10.51 yrs, SD=1.766) with same profiles of cognitive impairment participated. Study group received individual supervised rehabilitation twice a week during 6 weeks with FORAMENRehab software (Sarajuuri et al, 2000; adapted for children by authors), while waiting-list group received no training. Intervention effect for study group and control performance for waiting-list group was evaluated comparing baseline tasks after 6-week-period. Results were analyzed with Mann-Whitney U test. Results Significant improvement was seen for study group after intervention. In complex attention tasks they gave more correct responses (p Conclusion Neurorehabilitation with FORAMENRehab is effective for children with PE. Children significantly improved in two more complicated attention components: complex and tracking; and in three main visuospatial components: visual organization, attention and perception. Modern computer-assisted neurocognitive intervention could improve the fundamentals of learning in children with cognitive impairment.

Cauchy Graph Embedding Optimization for Built-Up Areas Detection From High-Resolution Remote Sensing Images

Automatic built-up areas detection from remote sensing images has attracted considerable research interest, due to its crucial roles in various applications. As far as built-up areas detection, the corner density map to predict the presence of the built-up areas has been widely adopted, but the calculation is generally time-consuming. In addition, the density map is just segmented by a statistical threshold, resulting in that the accurate boundaries of the built-up areas are unachievable. In order to address these issues, this paper proposes a novel built-up areas detection approach. Instead of pixel units, our approach takes the superpixel-based image partitions as the primary calculation units, which benefits to improve the computational efficiency and visual organization performance. Based on the superpixel-based units, this paper first proposes a sparse corner voting method for accelerating the production of corner density map. Then, Cauchy graph embedding optimization is presented to cope with the problem of segmenting the density map, which can preserve the well-defined boundaries of built-up areas. A diverse and representative test set including 2.1-m resolution ZY3 imagery, 2.0-m resolution GF1 imagery, 1.0-m resolution IKONOS imagery, and 0.61-m resolution QUICKBIRD imagery is collected. Experimental results on these test images show that our proposed approach is robust to sensor and resolution variation, and can outperform state-of-the-art approaches remarkably.

Transparallel mind: classical computing with quantum power

Inspired by the extraordinary computing power promised by quantum computers, the quantum mind hypothesis postulated that quantum mechanical phenomena are the source of neuronal synchronization, which, in turn, might underlie consciousness. Here, I present an alternative inspired by a classical computing method with quantum power. This method relies on special distributed representations called hyperstrings. Hyperstrings are superpositions of up to an exponential number of strings, which -- by a single-processor classical computer -- can be evaluated in a transparallel fashion, that is, simultaneously as if only one string were concerned. Building on a neurally plausible model of human visual perceptual organization, in which hyperstrings are formal counterparts of transient neural assemblies, I postulate that synchronization in such assemblies is a manifestation of transparallel information processing. This accounts for the high combinatorial capacity and speed of human visual perceptual organization and strengthens ideas that self-organizing cognitive architecture bridges the gap between neurons and consciousness.

Functional connectivity of visual cortex in the blind follows retinotopic organization principles.

Is visual input during critical periods of development crucial for the emergence of the fundamental topographical mapping of the visual cortex? And would this structure be retained throughout life-long blindness or would it fade as a result of plastic, use-based reorganization? We used functional connectivity magnetic resonance imaging based on intrinsic blood oxygen level-dependent fluctuations to investigate whether significant traces of topographical mapping of the visual scene in the form of retinotopic organization, could be found in congenitally blind adults. A group of 11 fully and congenitally blind subjects and 18 sighted controls were studied. The blind demonstrated an intact functional connectivity network structural organization of the three main retinotopic mapping axes: eccentricity (centre-periphery), laterality (left-right), and elevation (upper-lower) throughout the retinotopic cortex extending to high-level ventral and dorsal streams, including characteristic eccentricity biases in face- and house-selective areas. Functional connectivity-based topographic organization in the visual cortex was indistinguishable from the normally sighted retinotopic functional connectivity structure as indicated by clustering analysis, and was found even in participants who did not have a typical retinal development in utero (microphthalmics). While the internal structural organization of the visual cortex was strikingly similar, the blind exhibited profound differences in functional connectivity to other (non-visual) brain regions as compared to the sighted, which were specific to portions of V1. Central V1 was more connected to language areas but peripheral V1 to spatial attention and control networks. These findings suggest that current accounts of critical periods and experience-dependent development should be revisited even for primary sensory areas, in that the connectivity basis for visual cortex large-scale topographical organization can develop without any visual experience and be retained through life-long experience-dependent plasticity. Furthermore, retinotopic divisions of labour, such as that between the visual cortex regions normally representing the fovea and periphery, also form the basis for topographically-unique plastic changes in the blind.

Hierarchical Classes Analysis (HICLAS): A novel data reduction method to examine associations between biallelic SNPs and perceptual organization phenotypes in schizophrenia

The power of SNP association studies to detect valid relationships with clinical phenotypes in schizophrenia is largely limited by the number of SNPs selected and non-specificity of phenotypes. To address this, we first assessed performance on two visual perceptual organization tasks designed to avoid many generalized deficit confounds, Kanizsa shape perception and contour integration, in a schizophrenia patient sample. Then, to reduce the total number of candidate SNPs analyzed in association with perceptual organization phenotypes, we employed a two-stage strategy: first a priori SNPs from three candidate genes were selected (GAD1, NRG1 and DTNBP1); then a Hierarchical Classes Analysis (HICLAS) was performed to reduce the total number of SNPs, based on statistically related SNP clusters. HICLAS reduced the total number of candidate SNPs for subsequent phenotype association analyses from 6 to 3. MANCOVAs indicated that rs10503929 and rs1978340 were associated with the Kanizsa shape perception filling in metric but not the global shape detection metric. rs10503929 was also associated with altered contour integration performance. SNPs not selected by the HICLAS model were unrelated to perceptual phenotype indices. While the contribution of candidate SNPs to perceptual impairments requires further clarification, this study reports the first application of HICLAS as a hypothesis-independent mathematical method for SNP data reduction. HICLAS may be useful for future larger scale genotype-phenotype association studies.

Intellectual Functioning in Schizophrenia, Depression and Normal Control

Background: Schizophrenia is one of the most severe and disabling of all mental illnesses. The diagnosis of schizophrenia invoices a constellation of signs and symptoms and impairment in occupational and social functioning. Mood disorders are also important &amp; common psychiatric illnesses that represent a major cause of disability and mortality worldwide. Material and Methods: Sample of the study30 male and female Depression patients and a sample of 30 male and female schizophrenia patients was selected both from OPD. A control group of 30 persons from general population, matched according to age, sex, and education with schizophrenia patients, were taken as per Inclusion &amp; Exclusion criteria. The sample was selected using purposive sampling method. Samples were collected from P.G.I.B.M.S. Result: But post hoc analyses show that the schizophrenia and depressive groups differed significantly as the patients of depression had higher age mean than that of schizophrenia. Conclusion: Schizophrenia patients suffer from significant overall cognitive impairment; Have low concentration and inadequate visual organization. Depressive patients perform in a way similar to normal except in comprehension subtest.