Conceitos básicos de percepção de cena / Basic concepts of scene perception

A pesquisa sobre percepção de cenas é um esforço da comunidade científica em superar as dificuldades apresentadas ao estudo de estímulos complexos. As consistentes descobertas provaram a viabilidade do tema e encorajam uma abordagem mais holística e integrada nas investigações em percepção visual. Esse esforço e seus achados são, entretanto, pouco conhecidos pelos leitores em língua portuguesa e, até mesmo, entre alguns especialistas que se interessam pelo tema. O objetivo deste trabalho é fazer uma apresentação do campo, esboçar seu desenvolvimento, identificar suas principais questões e demonstrar sua pertinência e importância. Para isso, uma revisão seletiva de textos foi executada entre os autores que construíram os fundamentos da percepção de cenas. Ao concluir a leitura, espera-se que o leitor constate o papel relevante dos processos mnemônicos e do sujeito que observa no processo de captação visual do ambiente natural.

Scene perception research is a scientific community effort to overcome difficulties presented to the study of complex stimuli. Consistent findings support feasibility of the theme and encourage a more holistic and integrated approach to visual perception research. This effort and its findings are, however, poorly known by readers in Portuguese language, even among experts interested in the subject. The purpose of this paper is to introduce this field of research, outline its development, identify its main issues and demonstrate its relevance and importance. This task was accomplished by a selective review of papers from authors who built the foundations of scene perception. Upon completion of the reading, it is expected that the reader understands the relevant role of mnemonic processes and of the observer in the process of visual capture of natural environments.

Egocentric and allocentric spatial memory in healthy aging: performance on real-world tasks

Although normal aging has been related to several cognitive difficulties, other processes have been studied less, such as spatial memory. Our aim was to compare egocentric and allocentric memory in an elderly population using ecological tasks. Twenty-eight cognitively unimpaired participants performed Egocentric and Allocentric Spatial Memory Tasks, as well as Spatial Span from CANTAB, Benton's Judge of Line Orientation test (JoLO), and Montreal Cognitive Assessment test (MoCA). The results revealed that younger participants showed better performance than older participants on both the Egocentric and Allocentric Spatial Memory Tasks, although only the Egocentric test was able to discriminate between younger, middle, and older elderly participants. Learning effect was found in Allocentric Spatial Memory Task in younger and older groups, but not in the middle group. Allocentric and egocentric performance was not related to other visuospatial neuropsychological scores and gender did not influence performance in any task. Egocentric and Allocentric Spatial Memory Tasks may be useful tools in early screening for cognitive decline, as they are able to detect age differences in the cognitive unimpaired elderly population.

Subjective visual vertical with the bucket method in Brazilian healthy individuals / Vertical visual subjetiva com o método do balde em indivíduos brasileiros hígidos

ABSTRACT INTRODUCTION: The capacity of a healthy individual to estimate the true vertical in relation to the Earth when a fluorescent line is aligned in a completely dark room is called the subjective visual vertical. OBJECTIVE: To evaluate subjective visual vertical using the bucket method in healthy Brazilian individuals. METHODS: Binocular subjective visual vertical was measured in 100 healthy volunteers, 50 females and 50 males. The volunteers indicated the estimated position in which a fluorescent line inside a bucket reached the vertical position. A total of ten repetitions were performed, five clockwise and five counterclockwise. Data were tabulated and analyzed statistically. RESULTS: It was observed that the highest concentration of absolute values of vertical deviation was present up to 3°, regardless of gender, and the vertical deviation did not increase with age. The analysis of the mean of the absolute values of deviations from the vertical of 90% of the sample showed a maximum value of 2.6°, and at the analysis of 95%, the maximum value was 3.4° deviation from the vertical. CONCLUSION: The bucket method is easy to perform and interpret when assessing the deviation of the subjective visual vertical in relation to the true vertical in healthy Brazilian individuals.

Resumo Introdução: A capacidade que um indivíduo hígido tem em estimar a vertical verdadeira em relação à Terra, quando alinha uma linha fluorescente em uma sala completamente escura é denominada de Vertical Visual Subjetiva (VVS). Objetivo: Avaliar a VVS com o método do balde em indivíduos brasileiros hígidos. Método: A VVS binocular foi medida em 100 voluntários hígidos, 50 do gênero feminino e 50 do masculino. Os voluntários indicaram a posição estimada em que uma linha fluorescente no interior de um balde alcançou a posição vertical. Foram realizadas 10 repetições, cinco no sentido horário e cinco no anti-horário. Os dados foram tabulados e submetidos à análise estatística. Resultados: Observou-se que a maior concentração dos valores absolutos dos desvios da vertical esteve presente até 3º, independente do gênero e o desvio da vertical não aumentou conforme a idade. À análise da média dos valores absolutos dos desvios da vertical de 90% da amostra, foi encontrado o valor máximo de 2,6º e à análise de 95% o valor máximo foi de 3,4 de desvio da vertical. Conclusão: O método do balde é fácil de realizar e de interpretar na avaliação do desvio da vertical visual subjetiva em relação à vertical verdadeira de indivíduos brasileiros hígidos.

Prevalence and Spatial Concordance of Visual Field Deterioration in Fellow Eyes of Glaucoma Patients

PURPOSE: To examine the prevalence of visual field deterioration in contralateral eyes of patients with worsening open-angle glaucoma and to evaluate the spatial concordance of visual field deterioration between both eyes. METHODS: One hundred sixteen open-angle glaucoma patients who underwent 8 or more visual field examinations over > or =6 years of follow-up were included. The rates of the fast and slow components of visual field decay for each of 52 visual field test locations were calculated with point-wise exponential regression analysis. The spatial concordance of visual field deterioration in contralateral eyes was evaluated with a concordance ratio (calculated as the number of overlapping locations divided by the total number of deteriorating locations) and by comparing the rate of decay in corresponding modified glaucoma hemifield test clusters. RESULTS: The average visual field mean deviation (+/-standard deviation [SD]) was -8.5 (+/-6.4) dB and the mean (+/-SD) follow-up time was 9.0 (+/-1.6) years. Sixty-three patients had mild damage, 23 had moderate damage, and 30 had severe damage. The mean concordance ratio (+/-SD) was 0.46 (+/-0.32) for the mild group, 0.33 (+/-0.27) for the moderate group, and 0.35 (+/-0.21) for the severe group. Thirty-one patients (27%) had deterioration in concordant locations (p < 0.05). Visual field deterioration was greater in the superior hemifield than the inferior hemifield (p < 0.05) when evaluated with both the concordance ratio and modified glaucoma hemifield test cluster analysis methods. CONCLUSIONS: There is only fair spatial concordance with regard to visual field deterioration between the both eyes of an individual. We conclude that testing algorithms taking advantage of inter-eye spatial concordance would not be particularly advantageous in the early detection of glaucomatous deterioration.

Mapping the clockworks: what does the Clock Drawing Test assess in normal and pathological aging? / Mapeando as engrenagens: o que o Teste do Desenho do Relogio avalia no envelhecimento normal e patologico?

The Clock Drawing Test (CDT) is a cognitive screening tool used in clinical and research settings. Despite its role on the assessment of global cognitive functioning, the specific cognitive components required for test performance are still unclear. We aim to assess the role of executive functioning, global cognitive status, visuospatial abilities, and semantic knowledge on Shulman’s CDT performance. Fifty-three mild cognitive impairment, 60 Alzheimer’s dementia, and 57 normal elderly controls performed the CDT, the Frontal Assessment Battery, the Mini-Mental State Examination, the Stick Design Test, and a naming test (TN-LIN). An ordinal regression assessed specific neuropsychological influences on CDT performance. All the cognitive variables were related to the CDT, accounting for 53% of variance. The strongest association was between the CDT and executive functions, followed by global cognitive status, visuospatial processing, and semantic knowledge. Our result confirms the multidimensional nature of the test and the major role of executive functions on performance.

O Teste do Desenho do Relógio (TDR) é um instrumento de rastreio cognitivo amplamente usado em contextos clínicos e de pesquisa. Embora seu papel na avaliação do funcionamento cognitivo global seja reconhecido, os componentes específicos necessários à sua realização não são claros. Objetivo: avaliar a influência das funções executivas, estado cognitivo global, processamento visioespacial e conhecimento semântico no TDR. Realizaram o TDR, a Bateria de Avaliação Frontal, o Mini-Exame do Estado Mental, a Construção com Palitos, e um teste de nomeação (TN-LIN) 53 pacientes com comprometimento cognitivo leve, 60 com Alzheimer e 57 idosos normais.. A influência de variáveis neuropsicológicas específicas no TDR foi avaliada através de regressão ordinal. Todas as variáveis se relacionaram com o teste, respondendo por aproximadamente 53% da variância. A associação mais forte foi entre o TDR e as funções executivas, seguidas pela cognição geral, processamento visioespacial e conhecimento semântico. Nossos resultados confirmam a natureza multidimensional da tarefa e o papel das funções executivas em sua realização.

Procesamiento cortical de la visión: interacción de subsistemas parietales / Cortical processing of vision: parietal subsystems interaction

El procesamiento visual en el contexto de la neuropsicología exige la articulación de distintos niveles de análisis. Esto hace que el estudio de la visión se encuentre permeado por el avance en distintas disciplinas lo cual plantea como reto a la neuropsicología la construcción de un marco conceptual y de organización cerebral que permita la articulación de los vastos y distintos conocimientos que en la actualidad se tienen sobre el tema. Por tal motivo el presente artículo tiene como objetivo revisar los aportes de los principales modelos dicotómicos del procesamiento visual empleados en neuropsicología para detenernos con mayor detalle en la participación del Lóbulo Parietal Posterior y los retos que plantea a dichos modelos.

Visual processing requires, from a neuropsychological view, the integration of different analysis levels. This makes visual studies dependent on the advances produced by different scientific disciplines, leading into an increasing and comprehensive conceptual demand as well as more consistent brain functioning models. Thus, the aim of this article is to review the most outstanding dichotomic visual processing models used in neuropsychology, so as to painstakingly analyze the role of the Posterior Parietal Lobe and the risks taken by those different models.

A newmethod to analyze the subjective visual vertical in patients with bilateral vestibular dysfunction

OBJECTIVE: The aim of this study was to assess the subjective visual vertical in patients with bilateral vestibular dysfunction and to propose a new method to analyze subjective visual vertical data in these patients. METHODS: Static subjective visual vertical tests were performed in 40 subjects split into two groups. Group A consisted of 20 healthy volunteers, and Group B consisted of 20 patients with bilateral vestibular dysfunction. Each patient performed six measurements of the subjective visual vertical test, and the mean values were calculated and analyzed. RESULTS: Analyses of the numerical values of subjective visual vertical deviations (the conventional method of analysis) showed that the mean deviation was 0.326±1.13º in Group A and 0.301±1.87º in Group B. However, by analyzing the absolute values of the subjective visual vertical (the new method of analysis proposed), the mean deviation became 1.35±0.48º in Group A and 2.152±0.93º in Group B. The difference in subjective visual vertical deviations between groups was statistically significant (p,<0.05) only when the absolute values and the range of deviations were considered. CONCLUSION: An analysis of the absolute values of the subjective visual vertical more accurately reflected the visual vertical misperception in patients with bilateral vestibular dysfunction.

Software para avaliação da subjetiva vertical visual: um estudo transversal observacional / Software for subjective visual vertical assessment: an observational cross-sectional study

A orientação espacial em relação ao eixo gravitacional é de suma importância para a manu tenção da postura, marcha e para a maioria das atividades motoras realizadas pelo ser humano. A subjetiva vertical visual é um exame que avalia a percepção individual de verticalidade. OBJETIVOS: Os objetivos deste estudo foram: (1) desenvolver um sistema virtual para avaliar a subjetiva vertical visual, (2) produzir uma ferramenta simples para a prática clínica e (3) medir os valores da subjetiva vertical visual em indivíduos saudáveis usando a nova ferramenta. Forma de estudo: estudo obser vacional transversal. MÉTODO: Trinta voluntários saudáveis realizaram a subjetiva vertical visual em ambas as condições, estática e dinâmica. O exame consistia em ajustar uma linha virtual na posição vertical usando o mouse do computador. Na condição estática, a linha virtual foi projetada em uma tela branca. Na condição dinâmica, círculos pretos giravam no sentido horário e anti-horário. Seis medidas foram feitas e o desvio médio em relação a vertical real, calculado. RESULTADOS: Os desvios médios da subjetiva vertical visual foram: estática -0,372º ± 1,21; dinâmica sentido horário 1,53º ± 1,80 e dinâmica sentido anti-horário -1,11º ± 2,46. CONCLUSÃO: Este software mostrou ser prático e preciso para ser inserido na rotina de exames clínicos.

Spatial orientation in relation to the gravitational axis is significantly important for the maintenance of the posture, gait and for most of the human's motor activities. The subjective visual vertical exam evaluates the individual's perception of vertical orientation. OBJECTIVES: The aims of this study were (1) to develop a virtual system to evaluate the subjective visual vertical exam, (2) to provide a simple tool to clinical practice and (3) to assess the subjective visual vertical values of healthy subjects using the new software. Study Design: observational cross-sectional study. METHODS: Thirty healthy volunteers performed the subjective visual vertical exam in both static and dynamic conditions. The exam consisted in adjusting a virtual line in the vertical position using the computer mouse. For the static condition, the virtual line was projected in a white background. For the dynamic condition, black circles rotated in clockwise or counterclockwise directions. Six measurements were taken and the mean deviations in relation to the real vertical calculated. RESULTS: The mean values of subjective visual vertical measurements were: static -0.372º; ± 1.21; dynamic clockwise 1.53º ± 1.80 and dynamic counterclockwise -1.11º ± 2.46. CONCLUSION: This software showed to be practical and accurate to be used in clinical routines.

Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation

This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols.

Philadelphia Brief Assessment of Cognition in healthy and clinical Brazilian sample / Avaliação Cognitiva Breve da Filadélfia numa amostra brasileira clínica e saudável

The Philadelphia Brief Assessment of Cognition (PBAC) is a neuropsychological screening instrument that assesses five cognitive domains: working memory, visuospatial functioning, language, episodic memory and comportment. The aim is to verify if PBAC can properly be used in the Brazilian sample. Participated in this study: (a) 200 healthy volunteers - 100 young [21.6(2.5) years old] and 100 older adults [70.1(7.3) years old]; >12 years of education; (b) 30 Alzheimer's patients (AD) [73.7(5.7) years old], 4-11 years in education. The PBAC scores: (a) 95.8(2.6), 90.0(4.4) and (b) 65.0(10.8) were correlated with the Mini-Mental State Examination (MMSE) for young 29.1(0.9), older adults 28.3(1.4) and AD 18.4(3.0) groups. A positive correlation between MMSE and PBAC (r=0.9, p<0.001) was found. Negative correlations were observed between PBAC domains [memory (-0.63), visuospatial abilities (-0.44) and working memory (-0.3) tasks]. MANOVA showed a better male performance in visuospatial functioning (F=8.5, p=0.004). The Brazilian version of PBAC proved to be a promising screening instrument for clinical purposes.

O instrumento de rastreio neuropsicológico Philadelphia Brief Assessment of Cognition (PBAC) avalia cinco domínios cognitivos: memória de trabalho, habilidade visuoespacial, linguagem, memória episódica e comportamento. O objetivo é verificar a viabilidade do PBAC em amostra brasileira. Participaram: (a) 200 voluntários - 100 jovens com 21,6(2,5) anos e 100 idosos com 70,1(7,3) anos, ambos com média de escolaridade maior que 12 anos; (b) 30 pacientes com Alzheimer, com 73,7(5,7) anos e escolaridade entre 4 e 11 anos. Os escores do PBAC para os respectivos grupos (a) 95,8(2,6), 90(4,4) e (b) 65(10,8) foram correlacionados com o Mini Exame do Estado Mental (MEEM). Houve correlação positiva (r=0,9; p<0,001) entre MEEM e PBAC, e negativas entre os domínios do PBAC [memória (-0,63), habilidades visuoespaciais (-0,44) e memória de trabalho (-0,3)]. Foi demonstrado pela MANOVA melhor desempenho no funcionamento visuoespacial em homens (F=8,5, p=0,004). A versão brasileira do PBAC provou ser promissora como um instrumento de rastreio para propósitos clínicos.

The use of a neck brace does not influence visual vertical perception / O uso do colar cervical não influência na percepção de verticalidade visual

Subjective visual vertical (SVV) evaluates the individual's capacity to determine the vertical orientation. Using a neck brace (NB) allow volunteers' heads fixation to reduce cephalic tilt during the exam, preventing compensatory ocular torsion and erroneous influence on SVV result. OBJECTIVE: To analyze the influence of somatosensory inputs caused by a NB on the SVV. METHOD: Thirty healthy volunteers performed static and dynamic SVV: six measures with and six without the NB. RESULTS: The mean values for static SVV were -0.075º±1.15º without NB and -0.372º±1.21º with NB. For dynamic SVV in clockwise direction were 1.73º±2.31º without NB and 1.53º±1.80º with NB. For dynamic SVV in counterclockwise direction was -1.50º±2.44º without NB and -1.11º±2.46º with NB. Differences between measurements with and without the NB were not statistically significant. CONCLUSION: Although the neck has many sensory receptors, the use of a NB does not provide sufficient afferent input to change healthy subjects' perception of visual verticality.

A subjetiva vertical visual (SVV) avalia a capacidade do indivíduo determinar a posição vertical. O uso do colar cervical (CC) fixa a cabeça do voluntário, reduzindo a inclicação cefálica durante o exame e prevenindo a torção ocular compensatória que influencia na SVV. OBJETIVO: Analisar a influência de informações sometossensoriais causadas pelo uso de um CC na SVV. MÉTODO: Trinta voluntários saudáveis realizaram a SVV estática e dinâmica: seis medidas com e seis medidas sem o CC. RESULTADOS: O valor médio da SVV estática foi -0,075º±1,15º sem CC e -0,372º±1,21º com. Na SVV dinâmica no sentido horário foi 1,73º±2,31º sem CC e 1,53º±1,80º com. Na SVV dinâmica no sentido anti-horário foi -1,50º±2,44º sem CC e -1,11º±2,46º com. As diferenças entre as medidas com e sem CC não foram estatisticamente significativas. CONCLUSÃO: Apesar de o pescoço possuir inumeros receptores sensoriais, o uso do CC não fornece aferências suficientes para alterar a percepção de visual de verticalidade de voluntários saudáveis.

Tamanho e rigidez dos objetos influenciam os ajustes proximais e distais do alcance de crianças? / Can size and rigidity of objects influence infant's proximal and distal adjustments of reaching?

CONTEXTUALIZAÇÃO: Objetos influenciam nos ajustes do alcance de lactentes, no entanto ainda não se investigou se esses ajustes se modificam em crianças com mais idade. OBJETIVOS: Verificar se o tamanho e a rigidez dos objetos influenciam os ajustes proximais e distais do alcance dos 6 aos 8 meses e aos 36 meses de idade. MÉTODOS: A nove crianças saudáveis foram apresentados: um objeto rígido grande, um rígido pequeno, um maleável grande e um maleável pequeno. Os alcances foram filmados e posteriormente analisados qualitativamente quanto aos ajustes proximais (alcance uni e bimanual) e distais (orientação da mão horizontalizada, verticalizada e oblíqua; mão aberta, semiaberta e fechada) e a preensão desses objetos (com e sem). Foram aplicados o Teste de Friedman e as comparações múltiplas de Dunn, considerando-se 0,05 como diferença significativa. RESULTADOS: Constatou-se que, aos 36 meses, houve mais alcances unimanuais do que nas idades anteriores e, em todas as idades, os alcances unimanuais foram realizados principalmente para os objetos pequenos. Aos 36 meses, as crianças orientaram a mão horizontalizada para tocar e apreender os objetos, enquanto que, aos 6 e 7 meses, a orientação foi oblíqua para tocar e verticalizada para apreendê-los, independentemente das propriedades dos objetos. No decorrer dos meses, tanto no início quanto no final do alcance, as mãos tornaram-se mais abertas, principalmente para tocar o objeto rígido grande, e as crianças realizaram cada vez mais alcances com preensão, principalmente para os objetos maleáveis ou objetos pequenos. CONCLUSÕES: De 6 a 36 meses, os alcances tornaram-se mais refinados e ajustados às propriedades mais discrepantes dos objetos apresentados, o que se observou pelas modificações nos ajustes proximais e distais.

BACKGROUND: It has been found that objects influence the adjustments to reaching of breastfeeding infants, however, it has not been investigated whether these adjustments change in older infants. OBJECTIVES: The aim of this study was to determine whether the size and rigidity of objects influence the proximal and distal adjustments to reaching of infants of 6, 7, 8 and 36 months of age. METHODS: Nine healthy infants were presented with: one large rigid, one small rigid, one large malleable and one small malleable object. The movements were videotaped and later analyzed qualitatively with regard to proximal (unimanual and bimanual reaching) and distal adjustments (horizontal, vertical and oblique hand orientation, opened, half-open and closed hand) and with regard to grasping of these objects (with and without). Friedman test and Dunn multiple comparisons were applied and 0.05 was considered as a significant difference. RESULTS: Infants of 36 months of age performed more unimanual reaching than younger infants. Additionally, at all ages, unimanual reaching was particularly performed for small objects. At 36 months of age infants guided the hand horizontally to touch and grasp the objects, while at 6 and 7 months the hand orientation was oblique to touch and vertical to grasp the objects, regardless of the object's properties. Over the months, both at the beginning and at the end of reaching, the hands became more open, especially to touch the large rigid object, and infants increasingly performed reaching with successful grasping, especially for malleable or small objects. CONCLUSIONS: From 6 to 36 months of age, the reaching became more refined and the infants adjusted to the different properties of the objects which were observed through changes in the proximal and distal adjustments.

The Influence of Contrasts on Directional and Spatial Frequency Tuning in Visual Cortex Areas 17/18 of the Cat

PURPOSE: The purpose of this study was to investigate the effects of contrast display exposure on neuronal directional and spatial frequency tuning. Neuronal responses were recorded from ninety-four neurons in cortical areas 17 and 18 in two adult cats. METHODS: A multi-channel microelectrode was implanted in cortical areas 17 and 18 of two paralyzed and anaesthetized cats. Various drifting sinusoidal grating contrast displays were presented to one of the cats' eyes in the visual field. Contour plots based on the neuronal responses to the drifting sinusoidal grating displays using various contrasts (i.e., 0.4, 0.7, and 1.0) and velocities (i.e., 4.6, 13.9, 23.1, 32.3, 41.5, 50.8, and 60.0 deg/sec) were plotted as a function of the spatial frequency and the direction associated with each velocity and contrast used. RESULTS: Five parameters were extracted from these contour plots: 1) optimum response, 2) preferred direction, 3) optimum spatial frequency, 4) directional tuning width, and 5) spatial frequency bandwidth. To determine the optimal velocity, each parameter was plotted against each of the specific display contrasts used, and a 'best fit' line was established. Response amplitudes were dependent on the type of contrast utilized; however, the spatial frequency and directional tuning properties were stable for the cortical neurons assessed. CONCLUSIONS: The results of the presentation of different contrasts on neuronal directional and spatial frequency tuning are consistent with behavioral results when medium and high contrast displays are used.

Lateral asymmetry of voluntary attention orienting

We recently demonstrated that automatic attention favors the right side of space and, in the present study, we investigated whether voluntary attention also favors this side. Six reaction time experiments were conducted. In each experiment, 12 new 18-25-year-old male right-handed individuals were tested. In Experiments 1, 2, 3 (a, b) and 4 (a, b), tasks with increasing attentional demands were used. In Experiments 1, 2, 3a, and 4a, attention was oriented to one or both sides by means of a central spatially informative visual cue. A left or right side visual target appeared 100, 300, or 500 ms later. Attentional effects were observed in the four experiments. In Experiments 2, 3a and 4a, these effects were greater when the cue indicated the right side than when it indicated the left side (respectively: 16 ± 10 and 44 ± 6 ms, P = 0.015, for stimulus onset asynchrony of 500 ms in Experiment 2; 38 ± 10 and 70 ± 7 ms, P = 0.011, for Experiment 3a, and 23 ± 11 and 61 ± 10 ms, P = 0.009, for Experiment 4a). In Experiments 3b and 4b, the central cue pointed to both sides and was said to be non-relevant for task performance. In these experiments right and left reaction times did not differ. The most conservative interpretation of the present findings is that voluntary attention orienting favors the right side of space, particularly when a difficult task has to be performed.

Avaliação funcional do equilíbrio e da sensibilidade cutânea plantar de idosos moradores na comunidade / Balance and plantar cutaneous sensitivity functional assessment in community-dwelling elderly

Desequilíbrio é um dos muitos fatores de risco que aumenta a susceptibilidade de um idoso a quedas. O equilíbrio pode ser avaliado mediante testes posturais e de sensibilidade plantar. OBJETIVO: Avaliar a ocorrência de desequilíbrio e perda de sensibilidade cutânea plantar em idosos da comunidade e verificar a existência de associação entre ambas as alterações. CASUÍSTICA E MÉTODOS: Estudo transversal descritivo envolvendo 45 idosos submetidos à escala de equilíbrio de Berg (EEB) e ao teste de sensibilidade plantar com monofilamento de nylon. Foram utilizados os testes qui-quadrado e exato de Fisher e elaboradas curvas ROC para estudo da sensibilidade e especificidade da EEB. RESULTADOS: Idosos com alteração do equilíbrio e da sensibilidade cutânea foram em número de 2 e 4, respectivamente. Houve associação significativa entre queixa de desequilíbrio e perda da sensibilidade (p = 0,047) e ocorreu concordância razoável (Kappa: 0,6457) entre a EEB e o teste da sensibilidade. Verificou-se também associação significativa entre 6 dos 14 tarefas da EEB e o teste sensorial. CONCLUSÃO: Idosos vivendo com independência na comunidade, em sua maioria, apresentam equilíbrio e sensibilidade cutânea plantar normais. Quando alteradas estas funções mostram-se associadas de forma que, se os testes forem realizados conjuntamente, a precisão da avaliação do equilíbrio idoso aumenta.

Impaired balance is one of several factors that increase an elderly's susceptibility to falls. Balance assessment can be performed using postural tests and plantar cutaneous sensitivity tests. AIM: To assess balance disorders and loss of plantar cutaneous sensitivity in the elderly and look for association between these alterations. MATERIALS AND METHODS: A descriptive cross-sectional study involving 45 elderly submitted to the Berg Balance Scale (BBS) and the plantar sensitivity test with nylon monofilament. We used chi-square and Fisher's exact tests, and ROC curves were created in order to study the sensitivity and specificity of BBS. RESULTS: Two and 4 individuals showed balance and cutaneous sensation disorders, respectively. There was a significant association between the complaint of impaired balance and loss of skin sensitivity (p = 0.047), and there was a reasonable agreement (Kappa: 0.6457) between the BBS and the sensorial test. A significant association was also found among 6 of the 14 BBS tasks and the sensitivity test. CONCLUSION: Most of the elderly living independently in the community showed normal balance and plantar cutaneous sensation. When impaired, these functions appeared associated in a way that if the tests are performed together, the accuracy of the evaluation of the balance increases.

The progress in the study of visual field in spatial attention by event related potentials / 法医学杂志

Event-related potentials (ERP) is a good temporal resolution method to study the mechanism of visual field in brain. With the development of technique of high-density recording and brain imaging, the ERP is widely used in the location of the brain function. This article reviews the methods, results and primary conclusions in the field, and suggests several perspectives for the future research and application of ERP in the forensic science.

Estudio del deterioro cognitivo temprano entre enfermos de mal de Parkinson sin demencia / Study of early cognitive deterioration between Parkinson disease patients without dementia

The Parkinson disease (PD) was described in 1817 and it characterizes for showing neurodegenerative disorder with tremor, slow movements, rigidity and progressive difficulty for keeping posture and balance. More severe cognitive dysfunctions have been reported in PD patients who exhibited tremor at the onset of the illness in contrast with those of the acinetic/rigid subgroup; however, this point has not been cleared up yet. With the aim of studying the cognitive state of PD patients, a sample of PD idiopatic individuals was selected. The inclusion criteria which they had to comply with included an evolution of the disease inferior to 4 years and no cognitive damage for various causes. A battery of neuropsychological tests was used (Minimental Parkinson, Signoret, Stroop, Trail Making Test, Frontal Assessment Batery, Syndrom Kurztest Complex Figure of Rey), and some scale to classify patients as Rigid or Trembling were utilized (UPDRS, Hoehn & Yars). Considering also their functional status both groups presented a specific episodic immediate memory failure, worse in Trembling, a great Stroop effect, normal visuospatial and executive faculties and "Slight indication of organic mental disorder" (Syndrom Kurztest), without significant differences between them. No relationship was found between the functional stage, and the cognitive functions except for the A part of the Trail Making Test which proved a difference through the years. The early episodic memory deterioration founded without executive and visuospatial functions failure, although with that tendency, is remarkable.

La Enfermedad o Mal de Parkinson (EP) fue descrita en 1817 y se caracteriza por ser un trastorno neurodegenerativo cuyos síntomas principales son de tipo motriz. Sin embargo, en años reciente ha crecido la evidencia de que también se presenta con disfunción cognitiva temprana. Se seleccionó una muestra de pacientes con Mal de Parkinson idiopático, atendidos en dos Servicios de Neurología de adultos, con no más de 4 años de evolución en su enfermedad y con criterios de inclusión que descartaran deterioro cognitivo por otras causas, para un estudio descriptivo de tipo transversal. Los pacientes se clasificaron según los tipos Rígido y Tembloroso y el estadio funcional. Ambos grupos fueron sometidos a escalas de clasificación funcional (UPDRS, Hoehn y Yars) y una batería de pruebas neuropsicológicas (Mini Mental Parkinson, Signoret, Stroop, Trail Making Test, Frontal Assessment Battery, Syndrom Kurztest, Figura Compleja de Rey). Se encontró un deterioro específico de la memoria episódica inmediata, un gran efecto Stroop, facultades ejecutivas y visuoespaciales normales bajas y un "trastorno mental orgánico leve" en ambos grupos, sin diferencias estadísticas significativas entre ambos. No se encontró relación con el estadio funcional pero sí con el tiempo de evolución, en la prueba Trail Making parte A. Llama la atención el compromiso temprano de la memoria episódica, sin compromiso de las facultades ejecutivas y visuoespaciales, aunque con esa tendencia.

The parietal association cortex of the rat

Spatial cognition is a complex higher function in mammals and is involved in a variety of tasks that can be explored in the laboratory. In this review we will discuss the role of the posterior parietal/anteromedial cortex of rodents, also known as the parietal association cortex, and the hippocampal formation in spatial navigation. We will also discuss other higher associational functions of the posterior parietal/anteromedial cortex as they relate to Dr. Pinto-Hamuy's contribution to understanding behavioral functions.

Working memory in Parkinson's disease patients: clinical features and response to levodopa / Memória de trabalho em pacientes com doença de Parkinson: características clínicas e resposta a levodopa

OBJECTIVE: To evaluate the clinical features of the working memory (WM) in Parkinson's disease (PD) patients and to test the effect of levodopa on WM. METHOD: The paradigm was based on the 'n-back' tasks, which enables to study the level of executive demand (three levels of difficulty) and the domain of the information being processed (spatial items, faces and letters). The effect of levodopa was studied by testing PD patients in "on" and "off" states. RESULTS: PD patients performed less well in WM tasks than controls. There was no interaction between groups and complexity. Levodopa therapy had a positive effect only on spatial WM tasks but no effect on complexity. CONCLUSION: Our results suggest that impairment observed may result from a maintenance deficit within WM regardless the level of processing and levodopa therapy presents a positive effect on spatial WM.

OBJETIVO: Avaliar as características clínicas da memória de trabalho (MT) em pacientes com doença de Parkinson (DP) e testar o efeito da levodopa na MT. MÉTODO: O paradigma baseou-se nas tarefas 'n-back', que permitem avaliar o nível de demanda executiva (três níveis de dificuldade) e o domínio da informação sendo processado (posições espaciais, faces e letras). O efeito da levodopa foi estudado pela testagem dos pacientes no estado "on" e "off". RESULTADOS: Pacientes com DP apresentam desempenho inferior ao dos controles em tarefas de MT. Não foi observada interação entre grupos e complexidade. A terapia com levodopa mostrou efeito positivo sobre a modalidade espacial, e nenhum efeito sobre a complexidade. CONCLUSÃO: Nossos resultados sugerem que o comprometimento observado pode resultar de défict de manutenção da MT, independente do nível de processamento. A terapia com levodopa apresenta efeito positivo sobre a MT espacial.

Evidence for divided automatic attention

A long-standing debate in the literature is whether attention can form two or more independent spatial foci in addition to the well-known unique spatial focus. There is evidence that voluntary visual attention divides in space. The possibility that this also occurs for automatic visual attention was investigated here. Thirty-six female volunteers were tested. In each trial, a prime stimulus was presented in the left or right visual hemifield. This stimulus was characterized by the blinking of a superior, middle or inferior ring, the blinking of all these rings, or the blinking of the superior and inferior rings. A target stimulus to which the volunteer should respond with the same side hand or a target stimulus to which she should not respond was presented 100 ms later in a primed location, a location between two primed locations or a location in the contralateral hemifield. Reaction time to the positive target stimulus in a primed location was consistently shorter than reaction time in the horizontally corresponding contralateral location. This attentional effect was significantly smaller or absent when the positive target stimulus appeared in the middle location after the double prime stimulus. These results suggest that automatic visual attention can focus on two separate locations simultaneously, to some extent sparing the region in between.