Toward an Explanation of the Genesis of Ketamine-Induced Perceptual Distortions and Hallucinatory States

The NMDA receptor (NMDAR) channel has been proposed to function as a coincidence-detection mechanism for afferent and reentrant signals, supporting conscious perception, learning, and memory formation. In this paper we discuss the genesis of distorted perceptual states induced by subanesthetic doses of ketamine, a well-known NMDA antagonist. NMDAR blockage has been suggested to perturb perceptual processing in sensory cortex, and also to decrease GABAergic inhibition in limbic areas (leading to an increase in dopamine excitability). We propose that perceptual distortions and hallucinations induced by ketamine blocking of NMDARs are generated by alternative signaling pathways, which include increase of excitability in frontal areas, and glutamate binding to AMPA in sensory cortex prompting Ca++ entry through voltage-dependent calcium channels (VDCCs). This mechanism supports the thesis that glutamate binding to AMPA and NMDARs at sensory cortex mediates most normal perception, while binding to AMPA and activating VDCCs mediates some types of altered perceptual states. We suggest that Ca++ metabolic activity in neurons at associative and sensory cortices is an important factor in the generation of both kinds of perceptual consciousness.

Evaluation of reusable cardboard box designs: Biomechanical and perceptual aspects

Reusable cardboard boxes can be ergonomically designed for internal transportation of dry products in industrial settings. In this study we compared the effects of handling a regular commercial box and two cardboard prototypes on upper limb postures through the evaluation of movements, myoelectrical activity, perceived grip acceptability and capacity for reuse. The ergonomic designs provided a more acceptable grip, safer wrist and elbow movements and lower wrist extensors and biceps activity. Biomechanical disadvantages were observed only for one of the prototypes when handling to high surface. The prototypes were durable and suitable for extensive reuse (more than 2000 handlings) in internal industrial transportation. Despite being slightly more expensive than regular cardboard, the prototypes showed good cost-benefit considering their high durability. Relevance to industry: Cardboard boxes can be efficiently redesigned for allowing safer upper limb movements and lower muscle workload in manual materials handling. New designs can also be extensively reused for internal industrial transportation with good cost-benefit. © 2012 Elsevier B.V.

Um estudo histórico perceptual: a bandeira brasileira sem o Brasil

Pós-graduação em Artes - IA

Estudo perceptual da prosódia como elemento delimitador da estrutura de narrativas orais espontâneas: a diferença de tom

A presente pesquisa tem como tema o estudo perceptual da prosódia como elemento de segmentação de narrativas orais espontâneas e visa confirmar, ou não, se a prosódia facilita ao ouvinte leigo e inexperiente perceber a estrutura do texto narrativo. Este estudo investiga se a diferença de tom é um elemento prosódico relevante. A dissertação tem como corpus quatro narrativas espontâneas, as quais fazem parte do corpus analisado por Oliveira Jr.(2000), autor do projeto que inspirou esta pesquisa. Para saber se os participantes são capazes de delimitar a estrutura narrativa, baseando-se apenas no aspecto perceptual, conduziu-se um teste de percepção com 112 voluntários, recrutados na Universidade Federal do Pará e na Universidade Federal de Alagoas. Coube aos participantes a tarefa de indicar os pontos em que o falante teve a intenção de finalizar uma unidade comunicativa nas narrativas. A interpretação sobre unidade comunicativa foi subjetiva. Apresentou-se cada narrativa em quatro condições diferentes, a saber: (i) transcrição sem marca de pontuação e sem paragrafação; (ii) transcrição da narrativa acompanhada de áudio ; (iii) narrativa somente em áudio e (iv) áudio filtrado da narrativa, resultando numa versão deslexicalizada (fala ininteligível), mas com preservação da estrutura prosódica do discurso. Nas duas primeiras condições, a segmentação foi no texto transcrito, com barras transversais (/); nas demais, utilizou-se um programa de computador chamado ELAN. A análise dos dados obtidos baseou-se em tabelas, gráficos, análise estatística (teste do Qui-Quadrado), análise acústica (utilização do Programa PRAAT). Os resultados sinalizam que a prosódia ajuda o ouvinte leigo a perceber a estrutura básica do discurso narrativo. Com relação ao peso do Pitch Reset para auxiliar os ouvintes na demarcação de fronteiras, pode-se dizer que o teste estatístico do Qui-Quadrado encontrou evidências que lhe atribui essa função. Assim, neste contexto, ratifica-se o relevante papel da prosódia para o reconhecimento da estrutura de narrativas orais espontâneas e identifica-se o reflexo do peso da diferença de tom na percepção dos participantes.

Perceptual and acoustic parameters of vocal nodules in children

Vocal nodules constitute the major cause of dysphonia during childhood. Auditory-perceptual and acoustic vocal analyses have been used to differentiate vocal nodules from normal voice in children.Purpose: To study the value of auditory-perceptual and acoustic vocal analyses in assessments of children with nodules.Design: Diagnostic test study.Patients and interventions: A comparative study was carried out including 100 children with videolaryngoscopic diagnosis of vocal nodules (nodule group-NG); and 100 children without vocal symptoms and with normal videolaryngoscopic exams (control group-CG). The age range of both groups was between 4 and 11 years. All children underwent auditory-perceptual vocal analyses (GRBASI scale); maximum phonation time and s/z ratio were calculated, and acoustic vocal analysis (MDVP software) were carried out.Results: There was no difference in the values of maximum phonation time and s/z ratio between groups. Auditory-perceptual analysis indicated greater compromising of voice parameters for NG, compared to CG: G (79 versus 24), R (53 versus 3), B (67 versus 23) and S (35 versus 1). The values of acoustic parameters jitter, PPQ shimmer, APQ, NHR and SPI were higher for NG for CG. The parameter f0 did not differ between groups.Conclusion: Compromising of auditory-perceptual (G, R, B and S) and acoustic vocal parameters (jitter, PPQ shimmer, APQ, NHR and SPI) was greater for children with nodules than for those of the control group, which makes them important methods for assessing child dysphonia. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

Auditory perceptual performance of children in the identification of contrasts between stressed vowels

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia

Purpose: To verify the efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia. Methods: The participants were 20 students from third to fifth grade of a public elementary school in Marília, São Paulo, aged from 8 years to 11 years and 11 months, distributed into the following groups: Group I (GI; 10 students with developmental dyslexia) and Group II (GII; 10 students with good academic performance). A perceptual and visual-motor intervention program was applied, which comprised exercises for visual-motor coordination, visual discrimination, visual memory, visual-spatial relationship, shape constancy, sequential memory, visual figure-ground coordination, and visual closure. In pre- and post-testing situations, both groups were submitted to the Test of Visual-Perceptual Skills (TVPS-3), and the quality of handwriting was analyzed using the Dysgraphia Scale. Results: The analyzed statistical results showed that both groups of students had dysgraphia in pretesting situation. In visual perceptual skills, GI presented a lower performance compared to GII, as well as in the quality of writing. After undergoing the intervention program, GI increased the average of correct answers in TVPS-3 and improved the quality of handwriting. Conclusion: The developed intervention program proved appropriate for being applied to students with dyslexia, and showed positive effects because it provided improved visual perception skills and quality of writing for students with developmental dyslexia.

Differences in acoustic and perceptual parameters of the voice between elderly and young women at habitual and high intensity

The present study aimed to compare elderly and young female voices in habitual and high intensity. The effect of increased intensity on the acoustic and perceptual parameters was assessed. Sound pressure level, fundamental frequency, jitter, shimmer, and harmonic to noise ratio were obtained at habitual and high intensity voice in a group of 30 elderly women and 30 young women. Perceptual assessment was also performed. Both groups demonstrated an increase in sound pressure level and fundamental frequency from habitual voice to high intensity voice. No differences were found between groups in any acoustic variables on samples recorded with habitual intensity level. No significant differences between groups were found in habitual intensity level for pitch, hoarseness, roughness, and breathiness. Asthenia and instability obtained significant higher values in elderly than young participants, whereas, the elderly demonstrated lower values for perceived tension and loudness than young subjects. Acoustic and perceptual measures do not demonstrate evident differences between elderly and young speakers in habitual intensity level. The parameters analyzed may lack the sensitivity necessary to detect differences in subjects with normal voices. Phonation with high intensity highlights differences between groups, especially in perceptual parameters. Therefore, high intensity should be included to compare elderly and young voice.

Impact of inter-judge agreement on perceptual judgment of nasality

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Visual estimation of apertures for wheelchair locomotion in novices: perceptual judgment and motor practice

The aim of the present study was to determine the effects of motor practice on visual judgments of apertures for wheelchair locomotion and the visual control of wheelchair locomotion in wheelchair users who had no prior experience. Sixteen young adults, divided into motor practice and control groups, visually judged varying apertures as passable or impassable under walking, pre-practice, and post-practice conditions. The motor practice group underwent additional motor practice in 10 blocks of five trials each, moving the wheelchair through different apertures. The relative perceptual boundary was determined based on judgment data and kinematic variables that were calculated from videos of the motor practice trials. The participants overestimated the space needed under the walking condition and underestimated it under the wheelchair conditions, independent of group. The accuracy of judgments improved from the pre-practice to post-practice condition in both groups. During motor practice, the participants adaptively modulated wheelchair locomotion, adjusting it to the apertures available. The present findings from a priori visual judgments of space and the continuous judgments that are necessary for wheelchair approach and passage through apertures appear to support the dissociation between processes of perception and action.

Narrowing the gap of personalized medicine in emerging countries: the case of multiple endocrine neoplasias in Brazil

The finished version of the human genome sequence was completed in 2003, and this event initiated a revolution in medical practice, which is usually referred to as the age of genomic or personalized medicine. Genomic medicine aims to be predictive, personalized, preventive, and also participative (4Ps). It offers a new approach to several pathological conditions, although its impact so far has been more evident in mendelian diseases. This article briefly reviews the potential advantages of this approach, and also some issues that may arise in the attempt to apply the accumulated knowledge from genomic medicine to clinical practice in emerging countries. The advantages of applying genomic medicine into clinical practice are obvious, enabling prediction, prevention, and early diagnosis and treatment of several genetic disorders. However, there are also some issues, such as those related to: (a) the need for approval of a law equivalent to the Genetic Information Nondiscrimination Act, which was approved in 2008 in the USA; (b) the need for private and public funding for genetics and genomics; (c) the need for development of innovative healthcare systems that may substantially cut costs (e.g. costs of periodic medical followup); (d) the need for new graduate and postgraduate curricula in which genomic medicine is emphasized; and (e) the need to adequately inform the population and possible consumers of genetic testing, with reference to the basic aspects of genomic medicine.

PRoSPer: perceptual similarity queries in medical CBIR systems through user profiles

In this paper, we present a novel approach to perform similarity queries over medical images, maintaining the semantics of a given query posted by the user. Content-based image retrieval systems relying on relevance feedback techniques usually request the users to label relevant/irrelevant images. Thus, we present a highly effective strategy to survey user profiles, taking advantage of such labeling to implicitly gather the user perceptual similarity. The profiles maintain the settings desired for each user, allowing tuning of the similarity assessment, which encompasses the dynamic change of the distance function employed through an interactive process. Experiments on medical images show that the method is effective and can improve the decision making process during analysis.

Perceptual maps analysis for organic food consumers in China: a study on Shanghai consumers

Although in Europe and in the USA many studies focus on organic, little is known on the topic in China. This research provides an insight on Shanghai consumers’ perception of organic, aiming at understanding and representing in graphic form the network of mental associations that stems from the organic concept. To acquire, process and aggregate the individual networks it was used the “Brand concept mapping” methodology (Roedder et al., 2006), while the data analysis was carried out also using analytic procedures. The results achieved suggest that organic food is perceived as healthy, safe and costly. Although these attributes are pretty much consistent with the European perception, some relevant differences emerged. First, organic is not necessarily synonymous with natural product in China, also due to a poor translation of the term in the Chinese language that conveys the idea of a manufactured product. Secondly, the organic label has to deal with the competition with the green food label in terms of image and positioning on the market, since they are easily associated and often confused. “Environmental protection” also emerged as relevant association, while the ethical and social values were not mentioned. In conclusion, health care and security concerns are the factors that influence most the food consumption in China (many people are so concerned about food safety that they found it difficult to shop), and the associations “Safe”, “Pure and natural”, “without chemicals” and “healthy” have been identified as the best candidates for leveraging a sound image of organic food .

Contour integration and principles of perceptual grouping

Ziel der Arbeit ist die Analyse von Prinzipien der Konturintegration im menschlichen visuellen System. Die perzeptuelle Verbindung benachbarter Teile in einer visuellen Szene zu einem Ganzen wird durch zwei gestalttheoretisch begründete Propositionen gekennzeichnet, die komplementäre lokale Mechanismen der Konturintegration beschreiben. Das erste Prinzip der Konturintegration fordert, dass lokale Ähnlichkeit von Elementen in einem anderen Merkmal als Orientierung nicht hinreicht für die Entdeckung von Konturen, sondern ein zusätzlicher statistischer Merkmalsunterschied von Konturelementen und Umgebung vorliegen muss, um Konturentdeckung zu ermöglichen. Das zweite Prinzip der Konturintegration behauptet, dass eine kollineare Ausrichtung von Konturelementen für Konturintegration hinreicht, und es bei deren Vorliegen zu robuster Konturintegrationsleistung kommt, auch wenn die lokalen merkmalstragenden Elemente in anderen Merkmalen in hohem Maße zufällig variieren und damit keine nachbarschaftliche Ähnlichkeitsbeziehung entlang der Kontur aufweisen. Als empirische Grundlage für die beiden vorgeschlagenen Prinzipien der Konturintegration werden drei Experimente berichtet, die zunächst die untergeordnete Rolle globaler Konturmerkmale wie Geschlossenheit bei der Konturentdeckung aufweisen und daraufhin die Bedeutung lokaler Mechanismen für die Konturintegration anhand der Merkmale Kollinearität, Ortsfrequenz sowie der spezifischen Art der Interaktion zwischen beiden Merkmalen beleuchten. Im ersten Experiment wird das globale Merkmal der Geschlossenheit untersucht und gezeigt, dass geschlossene Konturen nicht effektiver entdeckt werden als offene Konturen. Das zweite Experiment zeigt die Robustheit von über Kollinearität definierten Konturen über die zufällige Variation im Merkmal Ortsfrequenz entlang der Kontur und im Hintergrund, sowie die Unmöglichkeit der Konturintegration bei nachbarschaftlicher Ähnlichkeit der Konturelemente, wenn Ähnlichkeit statt über kollineare Orientierung über gleiche Ortsfrequenzen realisiert ist. Im dritten Experiment wird gezeigt, dass eine redundante Kombination von kollinearer Orientierung mit einem statistischen Unterschied im Merkmal Ortsfrequenz zu erheblichen Sichtbarkeitsgewinnen bei der Konturentdeckung führt. Aufgrund der Stärke der Summationswirkung wird vorgeschlagen, dass durch die Kombination mehrerer Hinweisreize neue kortikale Mechanismen angesprochen werden, die die Konturentdeckung unterstützen. Die Resultate der drei Experimente werden in den Kontext aktueller Forschung zur Objektwahrnehmung gestellt und ihre Bedeutung für die postulierten allgemeinen Prinzipien visueller Gruppierung in der Konturintegration diskutiert. Anhand phänomenologischer Beispiele mit anderen Merkmalen als Orientierung und Ortsfrequenz wird gezeigt, dass die gefundenen Prinzipien Generalisierbarkeit für die Verarbeitung von Konturen im visuellen System beanspruchen können.

Diffusion maps in the Subriemannian motion group and perceptual grouping

Il presente lavoro è motivato dal problema della constituzione di unità percettive a livello della corteccia visiva primaria V1. Si studia dettagliatamente il modello geometrico di Citti-Sarti con particolare attenzione alla modellazione di fenomeni di associazione visiva. Viene studiato nel dettaglio un modello di connettività. Il contributo originale risiede nell'adattamento del metodo delle diffusion maps, recentemente introdotto da Coifman e Lafon, alla geometria subriemanniana della corteccia visiva. Vengono utilizzati strumenti di teoria del potenziale, teoria spettrale, analisi armonica in gruppi di Lie per l'approssimazione delle autofunzioni dell'operatore del calore sul gruppo dei moti rigidi del piano. Le autofunzioni sono utilizzate per l'estrazione di unità percettive nello stimolo visivo. Sono presentate prove sperimentali e originali delle capacità performanti del metodo.