Systematic review of visual illusions in schizophrenia.

Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the assumption of abnormal illusion perception in patients and, therefore, the validity of this approach. Here, we present a systematic review of the current evidence regarding visual illusion perception abnormalities in patients with schizophrenia. Relevant publications were identified by a systematic search of PubMed, Literatura LILACS, PsycINFO, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), IBECS, BIOSIS, and Web of Science. Forty-five studies were selected which included illusions classified as 'Motion illusions', 'Geometric-optical illusions', 'Illusory contours', 'Depth inversion illusion', and 'Non-specific'. There is concordant evidence of abnormal processing of illusions in patients for most categories, especially in facial Depth Inversion and Müller-Lyer illusions. There were significant methodological disparities and shortcomings, but risk of bias was overall low for individual studies. The usefulness of visual illusions as tools in clinical settings as well as in basic research may be contingent on significant methodological refinements.

Polymorphic color vision in captive Uta Hick's cuxiús, or bearded sakis (Chiropotes utahickae).

The pitheciines (Chiropotes, Pithecia, and Cacajao) are frugivorous Neotropical primates that specialize on the predation of seeds from unripe fruits, usually cryptic against the foliage. However, little is known about the color vision distribution within this taxon, and even less about the abilities shared by these animals regarding discrimination of chromatic targets. The aim of this study was to evaluate the color vision perception of captive Uta Hick's cuxiús, or bearded sakis (Chiropotes utahickae) through a behavioral paradigm of color visual discrimination, as well as to estimate, by genetic studies, the number and kinds of medium to long wavelength cone photopigment (opsins) encoded by this species. Among 12 cuxiús (7 males and 5 females) studied only 1 female was diagnosed as a trichromat. Results from genotyping were in line with our behavioral data and showed that cuxiús carried one (dichromat) or two (trichromat) medium to long wavelength pigments alleles, demonstrating a color vision polymorphism in C. utahickae similar to the majority of Neotropical Primates.

The adaptive value of primate color vision for predator detection.

The complex evolution of primate color vision has puzzled biologists for decades. Primates are the only eutherian mammals that evolved an enhanced capacity for discriminating colors in the green-red part of the spectrum (trichromatism). However, while Old World primates present three types of cone pigments and are routinely trichromatic, most New World primates exhibit a color vision polymorphism, characterized by the occurrence of trichromatic and dichromatic females and obligatory dichromatic males. Even though this has stimulated a prolific line of inquiry, the selective forces and relative benefits influencing color vision evolution in primates are still under debate, with current explanations focusing almost exclusively at the advantages in finding food and detecting socio-sexual signals. Here, we evaluate a previously untested possibility, the adaptive value of primate color vision for predator detection. By combining color vision modeling data on New World and Old World primates, as well as behavioral information from human subjects, we demonstrate that primates exhibiting better color discrimination (trichromats) excel those displaying poorer color visions (dichromats) at detecting carnivoran predators against the green foliage background. The distribution of color vision found in extant anthropoid primates agrees with our results, and may be explained by the advantages of trichromats and dichromats in detecting predators and insects, respectively.

[Risk factors associated with suicides in Palmas in the state of Tocantins, Brazil, between 2006 and 2009 investigated by psycho-social autopsy]. / Fatores de risco relacionados com suicídios em Palmas (TO), Brasil, 2006-2009, investigados por meio de autópsia psicossocial.

The scope of this article is to analyze and describe the risk factors and determinants linked to 24 suicides in the city of Palmas in the state of Tocantins between 2006 and 2009. The psychological and psycho-social autopsy method was used in order to investigate the consummated suicides by interviewing family members. It contextualized the subjects' life characteristics to understand the family dynamics and the affective, social, economic and cultural background, based on the reconstruction of the history and personality of the individuals. The associated socio-economic factors were: being male, aged between 20 and 40, single, with mixed ethnicity and basic education. The major risk factors identified were: mental disorder, alcohol and other drug abuse, disturbed family relationship and a history of previous suicide attempts. An attempt was made to contextualize and reflect on some cases reported by family members, as well as on the response of the health care teams to the demands of the families. The need to implement prevention programs and to train the primary health care professionals was considered a priority.

Fatores de risco relacionados com suicidios em Palmas (TO), Brasil, 2006-2009, investigados por meio de autopsia psicossocial / Risk factors associated with suicides in Palmas in the state of Tocantins, Brazil, between 2006 and 2009 investigated by psycho-social autopsy

Este artigo objetiva analisar e descrever os fatores de risco e seus determinantes, associados a 24 casos de suicídios ocorridos na cidade de Palmas (TO), no período de 2006 a 2009. Utilizou-se o método de autópsia psicológica e psicossocial, a qual, por meio de entrevistas com familiares, busca investigar os suicídios consumados, contextualizando características da vida do sujeito, e compreender os processos familiares e as circunstâncias afetivas, sociais, econômicas e culturais, fundamentando-se na reconstrução da história e da personalidade da pessoa. Os fatores socioeconômicos associados foram: ser do sexo masculino, solteiro, de cor parda, estar na faixa etária de 20 a 40 anos e com ensino fundamental. Os principais fatores de risco identificados foram: transtornos mentais, abuso de álcool e outras drogas, relacionamento familiar conturbado e histórico de tentativas anteriores. Buscamos contextualizar e refletir sobre alguns casos relatados pelos familiares e sobre a resposta das equipes de saúde às demandas das famílias. A necessidade de implantar programas de prevenção e de capacitar os profissionais da atenção básica foi verificada. .

The scope of this article is to analyze and describe the risk factors and determinants linked to 24 suicides in the city of Palmas in the state of Tocantins between 2006 and 2009. The psychological and psycho-social autopsy method was used in order to investigate the consummated suicides by interviewing family members. It contextualized the subjects' life characteristics to understand the family dynamics and the affective, social, economic and cultural background, based on the reconstruction of the history and personality of the individuals. The associated socio-economic factors were: being male, aged between 20 and 40, single, with mixed ethnicity and basic education. The major risk factors identified were: mental disorder, alcohol and other drug abuse, disturbed family relationship and a history of previous suicide attempts. An attempt was made to contextualize and reflect on some cases reported by family members, as well as on the response of the health care teams to the demands of the families. The need to implement prevention programs and to train the primary health care professionals was considered a priority. .

Financial expense incurred by medical leaves of health professionals in Rondonia public hospitals, Brazil.

The study investigates the additional payroll expense caused by absenteeism due to illness among nursing professionals and physicians at two public hospitals at Cacoal, Rondonia, Brazil. Non-programmed absences of up to 15 days which occurred at the hospital units between 2004 to 2007 were verified in the database of the institutions human resource sector. From 1,704 non-programmed absences, 1,486 were justified by medical declarations. It was verified that absenteeism caused by illness was responsible for 87.2% of all non-programmed absences. When these data are grouped by professional categories, it was observed that the nurse absenteeism due to illness reached 83.3%, when compared with 16.7% for physicians. The general absenteeism index, adding up nurses and physicians, corresponded to 0.85%, resulting in an additional payroll expense of 5.2% and 7.4% in the salaries of nursing professionals and physicians, respectively.

Financial expense incurred by medical leaves of health professionals in Rondonia public hospitals, Brazil / Gasto financeiro ocasionado pelos atestados médicos de profissionais da saúde em hospitais públicos no Estado de Rondônia, Brasil / El gasto financiero causado por las licencias médicas de profesionales de la salud en los hospitales públicos en Rondonia, Brasil

The study investigates the additional payroll expense caused by absenteeism due to illness among nursing professionals and physicians at two public hospitals at Cacoal, Rondonia, Brazil. Non-programmed absences of up to 15 days which occurred at the hospital units between 2004 to 2007 were verified in the database of the institutions’ human resource sector. From 1,704 non-programmed absences, 1,486 were justified by medical declarations. It was verified that absenteeism caused by illness was responsible for 87.2 percent of all non-programmed absences. When these data are grouped by professional categories, it was observed that the nurse absenteeism due to illness reached 83.3 percent, when compared with 16.7 percent for physicians. The general absenteeism index, adding up nurses and physicians, corresponded to 0.85 percent, resulting in an additional payroll expense of 5.2 percent and 7.4 percent in the salaries of nursing professionals and physicians, respectively.

O objetivo deste estudo foi investigar o gasto adicional na folha de pagamento, causado pelo absenteísmo doença de profissionais de enfermagem e médicos, em dois hospitais públicos da cidade de Cacoal, Rondônia, Brasil. Foram verificadas ausências não programadas de até 15 dias nas unidades hospitalares, no período de 2004 a 2007, observadas no banco de dados do setor de recursos humanos das instituições. Constatou-se 1.704 ausências não programadas, das quais 1.486 são justificadas por atestados médicos. Verificou-se que o absenteísmo por motivo de doença foi responsável por 87,2 por cento das ausências não programadas. Se for descrito por categoria de profissional, o absenteísmo doença dos profissionais de enfermagem atingiu índice de 83,3 por cento e dos médicos 16,7 por cento. O índice do absenteísmo geral dos profissionais de enfermagem e médicos foi de 0,85 por cento, enquanto que o gasto adicional na folha de pagamento no período atingiu 5,2 por cento nos vencimentos dos profissionais de enfermagem e 7,4 por cento dos médicos.

El objetivo de este estudio fue investigar el gasto adicional en la planilla de pago, causado por el absentismo enfermedad de profesionales de enfermería y médicos, en dos hospitales públicos de la ciudad de Cacoal, en Rondonia, Brasil. Fueron verificadas ausencias no programadas de hasta 15 días en las unidades hospitalarias, en el período de 2004 a 2007, constatadas en el banco de datos del sector de recursos humanos de las instituciones. Se constató 1.704 ausencias no programadas, de las cuales 1.486 son justificadas con certificados médicos. Se verificó que el absentismo por motivo de enfermedad fue responsable por 87,2 por ciento de las ausencias no programadas. Si fuese descrito por categoría profesional, el absentismo enfermedad de los profesionales de enfermería alcanzaría el índice de 83,3 por ciento y el de los médicos 16,7 por ciento. El índice de absentismo general de los profesionales de enfermería y médicos fue de 0,85 por ciento, en cuanto que el gasto adicional en la planilla de pago en el período alcanzó 5,2 por ciento en los salarios de los profesionales de enfermería y 7,4 por ciento de los médicos.

Detection of fruit by the Cerrado's marmoset (Callithrix penicillata): modeling color signals for different background scenarios and ambient light intensities.

Among placental mammals, only primates have trichromatic color vision, however this is not a uniform condition. Under different genetic status, Old World monkeys have routine trichromacy, while New World monkeys show a visual polymorphism, characterized by obligatory male dichromacy. The ecological role of this genetic difference still remains unclear, but some studies show that dichromats and trichromats appear to have different abilities in detecting colored targets against a background of leaves. The Cerrado's marmoset (Callithrix penicillata) is known to forage in brightly illuminated (savanna-like vegetation) and dimly illuminated (forests) environments, exploiting a high amount of dark fruits. Hence, it seems to be a good model for studying the differential advantages enjoyed by each color vision phenotype under natural conditions. Our aim was to verify how the different phenotypes of Cerrado's marmoset detect components of their diet, evaluating the existence of differential phenotype advantages. Under two different light conditions, visual signals of naturally consumed fruits were modeled against different backgrounds scenarios. Even though dichromats and trichromats appear to be equally suited for tasks involving fruit detection, phenotype differential advantages are observed in this marmoset. In many conditions trichromats are predicted to perform better than dichromats, but under low ambient light dichromats manage to outperform trichromats in some scenarios. Phenotypes that carry widely spaced and longer M/L pigments enjoy the most advantage. These differential performances of trichromatic phenotypes, together with overdominance selection, seem to explain the maintenance of the tri-allelic system found in callitrichids.

Low frequency (0.5Hz) rTMS over the right (non-dominant) motor cortex does not affect ipsilateral hand performance in healthy humans.

Reduction of excitability of the dominant primary motor cortex (M1) improves ipsilateral hand function in healthy subjects. In analogy, inhibition of non-dominant M1 should also improve ipsilateral performance. In order to investigate this hypothesis, we have used slow repetitive transcranial magnetic stimulation (rTMS) and the Purdue Pegboard test. Twenty-eight volunteers underwent 10 minutes of either 0.5Hz rTMS over right M1 or sham rTMS (coil perpendicular to scalp). The motor task was performed before, immediately after, and 20 minutes after rTMS. In both groups, motor performance improved significantly throughout the sessions. rTMS inhibition of the non-dominant M1 had no significant influence over ipsilateral or contralateral manual dexterity, even though the results were limited by unequal performance between groups at baseline. This is in contrast to an improvement in left hand function previously described following slow rTMS over left M1, and suggests a less prominent physiological transcallosal inhibition from right to left M1.

Low frequency (0.5Hz) rTMS over the right (non-dominant) motor cortex does not affect ipsilateral hand performance in healthy humans / A inibição do córtex motor não-dominante por meio da estimulação magnética transcraniana a 0, 5Hz não interfere no desempenho manual ipsilateral de sujeitos hígidos

Reduction of excitability of the dominant primary motor cortex (M1) improves ipsilateral hand function in healthy subjects. In analogy, inhibition of non-dominant M1 should also improve ipsilateral performance. In order to investigate this hypothesis, we have used slow repetitive transcranial magnetic stimulation (rTMS) and the Purdue Pegboard test. Twenty-eight volunteers underwent 10 minutes of either 0.5Hz rTMS over right M1 or sham rTMS (coil perpendicular to scalp). The motor task was performed before, immediately after, and 20 minutes after rTMS. In both groups, motor performance improved significantly throughout the sessions. rTMS inhibition of the non-dominant M1 had no significant influence over ipsilateral or contralateral manual dexterity, even though the results were limited by unequal performance between groups at baseline. This is in contrast to an improvement in left hand function previously described following slow rTMS over left M1, and suggests a less prominent physiological transcallosal inhibition from right to left M1.

A redução da excitabilidade do córtex motor primário (M1) dominante melhora o desempenho manual ipsilateral: a inibição do M1 não-dominante poderia, analogamente, aprimorar a função manual direita. Para investigar esta hipótese, utilizou-se a estimulação magnética transcraniana repetitiva (EMTr) de baixa frequência e o teste Purdue Pegboard. Submetemos 28 voluntários a 10 minutos de EMTr sobre o M1 direito (0,5 Hz) ou a EMTr placebo (bobina perpendicular ao escalpo). O teste foi executado antes, imediatamente após e 20 minutos após a EMTr. Nos dois grupos, o desempenho manual mostrou significativa melhora entre as sessões. A inibição do M1 não-dominante não influenciou significativamente a destreza motora ipsi ou contralateral, apesar da conclusão limitada pelo desempenho discrepante dos grupos na primeira sessão. Este resultado contrasta com a melhora da função manual esquerda descrita após a EMTr sobre o M1 esquerdo e sugere uma inibição transcalosa fisiológica menos intensa do M1 direito para o esquerdo.

[Low prevalence of dyschromatopsia using the fourth edition of HRR (Hardy, Rand and Rittler) pseudoisochromatic plate test among the Indian population of Lalima village, Terena]. / Baixa prevalência de discromatopsia, pela 4a edição do teste pseudoisocromático HRR (Hardy, Rand e Rittler), da população indígena de etnia terena da aldeia lalima na região de Miranda: Mato Grosso do Sul.

PURPOSE: to evaluate the frequency of dyschromatopsias among the 10 to 45-year-old male Indian population of Lalima village, Terena ethnicity, in Miranda-MS, using the fourth edition of the pseudoisochromatic HRR test (Hardy, Rand and Rittler). METHODS: Lalima village in Miranda-MS was visited in January and February 2005. The visits only occurred after the approval of the project by the Committee of Ethics and Research of UFMS, by the National Committee of Ethics and Research, by the Indian National Foundation, and by the chief of Lalima village. The test was applied in 226 Indians who had been previously submitted to ophthalmologic examination for the detection of abnormalities that could doubt the applicability of the test. The test was performed under natural illumination, in sunny days, however with no direct sunlight. The test was applied and analyzed by the same experimenter in all the Indians. RESULTS: Two hundred and twenty-six men were examined (60.1%) of the total male population of 376 individuals between 10 and 45 years old who live in Lalima village. No cases of dyschromatopsia were found in this population examined with the HRR test. CONCLUSIONS: Once it is known that incidence of dyschromatopsias among the white male Caucasian population is about 6-8%, the results of the present study indicate a low prevalence of dyschromatopsias in this Indian population of Terena ethnicity, since no cases were detected in the examined sample. Other studies using different methods must be made to reinforce the present results. It would also be interesting to genetically examine this population and verify the genes that code for photopigments.

Perception of the Müller-Lyer illusion in capuchin monkeys (Cebus apella).

Visual illusions are formed by differences between the perception of one figure and its real physical characteristics. The Müller-Lyer illusion is the best known and most studied geometric illusion, consisting in the subject's judgment between two parallel lines that have the same size, one flanked with outward-pointing arrowheads, and the other with inward-pointing arrowheads. These arrowheads act as inductors that make the lines to be perceived as having different sizes, inward-pointing stimuli being estimated as longer. This study aimed to investigate the Müller-Lyer illusion in capuchin monkeys (Cebus apella), a New World primate not yet investigated for this illusion. For this purpose, stimuli were presented on a touch screen monitor. Ten adult subjects (five females and five males) were used. Before the tests, they were trained to discriminate between two physically different lines with and without arrowheads. The longer lines were always the positive (rewarded) stimuli. Regarding the Müller-Lyer Illusion test, all monkeys, unrespective of gender, demonstrated susceptibility to the illusion, by choosing preferentially the line with inward-pointing arrowheads. In order to determine the degree of the illusion, a point of subjective equality test (PSE) was performed. The PSE without arrowheads values were lower than the PSE with arrowheads. Thus, it was demonstrated that capuchin monkeys were susceptible to the Müller-Lyer illusion, once the perception of the lines' size was influenced by the presence of the arrowheads and by their orientation.

Perceptual filling-in of stereoscopically presented targets.

PURPOSE: To investigate the influence of parametric variation on the filling-in latency of stereoscopically presented stimuli. METHODS: Anaglyphs were created using two circular patches of 0.3 masculine diameter, 0.5 masculine disparity and 6 masculine eccentricity from fixation point. Targets were presented at the visual field midline, 90 masculine and 270 masculine positions, with crossed and uncrossed disparity. The time elapsed for disappearance of the target under voluntary steady fixation was computed. Eighteen subjects tested. RESULTS: There was no significant difference between crossed and uncrossed disparities, nor between near or far from the vertical horopter line. The significant difference was between upper and lower visual field positions. CONCLUSION: The results show that: (i) stereoscopic presentation does not influence the target filling-in latency; (ii) differences between dorsal and ventral visual stream might influence target filling-in latency.

Baixa prevalência de discromatopsia, pela 4ª edição do teste pseudoisocromático HRR (Hardy, Rand e Rittler), da população indígena de etnia terena da aldeia lalima na região de Miranda: Mato Grosso do Sul / Low prevalence of dyschromatopsia using the fourth edition of HRR (Hardy, Rand and Rittler) pseudoisochromatic plate test among the Indian population of Lalima village, Terena

OBJETIVO: Avaliar a freqüência de discromatopsias através da 4ª edição do teste pseudoisocromático HRR (Hardy, Rand and Rittler) entre a população indígena masculina da aldeia Lalima, etnia Terena, na região de Miranda-MS. MÉTODOS: Foram realizadas viagens à aldeia Lalima em Miranda-MS, nos meses de janeiro e fevereiro de 2005. As viagens para realizar os exames só foram iniciadas após o projeto ter sido avaliado e aprovado pelos Comitê de Ética e Pesquisa da UFMS, Comitê Nacional de Ética e Pesquisa, Fundação Nacional do índio e do cacique da aldeia Lalima. O teste HRR foi aplicado em 226 índios após terem sido submetidos a exame oftalmológico para detecção de anormalidades que pudessem comprometer a aplicabilidade do teste. O teste foi realizado sob luz natural, em dias ensolarados, sem incidência direta de sol. O teste foi aplicado e interpretado pelo mesmo examinador em todos os índios. RESULTADOS: Realizaram-se 226 exames (60,1 por cento) de uma população de 376 homens entre 10 e 45 anos de idade, que vivem na Aldeia Lalima. Não foi encontrado nenhum caso de discromatopsia na população examinada com o teste HRR. CONCLUSÃO: O resultado do presente estudo mostra a baixa prevalência de discromatopsia nesta população indígena de etnia Terena, uma vez que não se detectou nenhum caso de discromatopsia na população estudada, sendo a prevalência de discromatopsia entre homens caucasianos de 6 a 8 por cento. A ausência de discromatopsia na população estudada, no entanto, deve ser mais bem avaliada tentando aumentar o tamanho da amostra, utilização de outros testes e, principalmente, por estudos genéticos para verificar os genes codificadores dos fotopigmentos para melhor compreensão das condições relacionadas à visão de cores dessa comunidade indígena.

PURPOSE: to evaluate the frequency of dyschromatopsias among the 10 to 45-year-old male Indian population of Lalima village, Terena ethnicity, in Miranda-MS, using the fourth edition of the pseudoisochromatic HRR test (Hardy, Rand and Rittler). METHODS: Lalima village in Miranda-MS was visited in January and February 2005. The visits only occurred after the approval of the project by the Committee of Ethics and Research of UFMS, by the National Committee of Ethics and Research, by the Indian National Foundation, and by the chief of Lalima village. The test was applied in 226 Indians who had been previously submitted to ophthalmologic examination for the detection of abnormalities that could doubt the applicability of the test. The test was performed under natural illumination, in sunny days, however with no direct sunlight. The test was applied and analyzed by the same experimenter in all the Indians. RESULTS: Two hundred and twenty-six men were examined (60.1 percent) of the total male population of 376 individuals between 10 and 45 years old who live in Lalima village. No cases of dyschromatopsia were found in this population examined with the HRR test. CONCLUSIONS: Once it is known that incidence of dyschromatopsias among the white male Caucasian population is about 6-8 percent, the results of the present study indicate a low prevalence of dyschromatopsias in this Indian population of Terena ethnicity, since no cases were detected in the examined sample. Other studies using different methods must be made to reinforce the present results. It would also be interesting to genetically examine this population and verify the genes that code for photopigments.

Perceptual filling-in of stereoscopically presented targets

PURPOSE: To investigate the influence of parametric variation on the filling-in latency of stereoscopically presented stimuli. METHODS: Anaglyphs were created using two circular patches of 0.3° diameter, 0.5° disparity and 6° eccentricity from fixation point. Targets were presented at the visual field midline, 90° and 270° positions, with crossed and uncrossed disparity. The time elapsed for disappearance of the target under voluntary steady fixation was computed. Eighteen subjects tested. RESULTS: There was no significant difference between crossed and uncrossed disparities, nor between near or far from the vertical horopter line. The significant difference was between upper and lower visual field positions. CONCLUSION: The results show that: (i) stereoscopic presentation does not influence the target filling-in latency; (ii) differences between dorsal and ventral visual stream might influence target filling-in latency.

OBJETIVO: Investigar a influência da variação de parâmetros estereoscópicos na latência de preenchimento perceptual de estímulos 3D. MÉTODOS: Criados anáglifos com dois discos de 0,3° de diâmetro, 0,5° de disparidade e 6° de excentricidade do ponto central de fixação. Estímulos foram apresentados na linha central do campo visual, nas posições 90° e 270°, com disparidade cruzada e não cruzada. Registrado o tempo gasto para o preenchimento do estímulo sob fixação estável. Testados dezoito indivíduos. RESULTADOS: Não houve diferença significativa entre as disparidades cruzada e não cruzada, nem entre perto e longe da linha do horóptero vertical. Houve diferença significativa entre posição superior e inferior do campo visual. CONCLUSÕES: Os resultados mostram que: (i) a apresentação estereoscópica não tem influência na latência de preenchimento perceptual, (ii) diferenças entre o sistema visual dorsal e ventral podem influenciar a latência de preenchimento perceptual.