Neuronal Response to Reward and Luminance in Macaque LIP During Saccadic Choice / 神经科学通报·英文版

Recent work in decision neuroscience suggests that visual saliency can interact with reward-based choice, and the lateral intraparietal cortex (LIP) is implicated in this process. In this study, we recorded from LIP neurons while monkeys performed a two alternative choice task in which the reward and luminance associated with each offer were varied independently. We discovered that the animal's choice was dictated by the reward amount while the luminance had a marginal effect. In the LIP, neuronal activity corresponded well with the animal's choice pattern, in that a majority of reward-modulated neurons encoded the reward amount in the neuron's preferred hemifield with a positive slope. In contrast, compared to their responses to low luminance, an approximately equal proportion of luminance-sensitive neurons responded to high luminance with increased or decreased activity, leading to a much weaker population-level response. Meanwhile, in the non-preferred hemifield, the strength of encoding for reward amount and luminance was positively correlated, suggesting the integration of these two factors in the LIP. Moreover, neurons encoding reward and luminance were homogeneously distributed along the anterior-posterior axis of the LIP. Overall, our study provides further evidence supporting the neural instantiation of a priority map in the LIP in reward-based decisions.

A randomized controlled trial on the effect of Lutein Supplementation on Macular Pigment Optical Density and Macular Function in Pseudophakic Patients

Objective@#To evaluate the efficacy of oral lutein supplementation on macular pigment optical density (MPOD) levels and macular function in pseudophakic eyes that underwent phacoemulsification. @*Methods@#This was a prospective, randomized, parallel-arm, single-masked study comparing oral lutein supplement 20 mg/tablet (Lutax 20) with non-supplementation in pseudophakic eyes. We assessed MPOD, low-luminance deficit (LLD), visual recovery time (VRT) using photostress test, and adverse events. One hundred twenty-eight (128) eyes were enrolled and randomized 1:1 to active treatment (lutein supplementation) or no treatment (no supplementation). The supplementation period was 12 weeks and patients were assessed every 4 weeks over a period of 16 weeks.@*Results@#Sixty-four (64) eyes in each group completed the study. A significant increase in MPOD (p<0.001) was observed in the lutein supplemented group, from 0.36 DU at baseline to 0.55 DU at week 12, with a mean increase of 6.32 ± 1.72% per 4 weeks of supplementation compared with a mean MPOD decrease rate of 0.63 ± 0.48% in the non-supplementation group. A significant reduction in LLD was observed in the lutein-treated group, from LogMAR 0.063 at baseline to LogMAR 0.023 at Week 12 (p=0.003). VRT was also significantly shorter in the treatment from a baseline of 83.06 to 68.80 seconds at Week 12 (p<0.001).@*Conclusion@#Lutein supplementation (20 mg/tablet; Lutax 20) demonstrated a significant degree of MPOD augmentation, and reductions in LLD and VRT among patients who underwent phacoemulsification with lens implantation.

Study on the Photoelectric Performance Indicators of Medical Electronic Endoscope / 中国医疗器械杂志

OBJECTIVE@#To establish a method for measuring the photoelectric performance index (luminance response characteristic and luminance tolerance) of medical electronic endoscope.@*METHODS@#Based on the clinical application and product features of medical electronic endoscope, the umbrella grayscale test chart and the adjustable gray scale test chart are designed and made from two aspects of distribution and density differential.@*RESULTS@#The influence of gray scale arrangement, background illumination intensity and illumination spectrum on photoelectric performance measurement of electronic endoscope is verified by test.@*CONCLUSIONS@#It is a reference for the design analysis, evaluation and modification of electronic endoscope product photoelectric part, whether it is suitable for fast detection of umbels and more accurate gray scale test chart.

Inter-trial effect in luminance processing revealed by magnetoencephalography / Efecto inter-ensayo en el procesamiento de iluminación revelado por magnetoencefalografía

In this study, we examined whether luminance processing in the human visual system would exhibit any history effect (i.e., inter-trial modulation) in psychophysical and magnetoencephalographic experiments. A disk was presented against a black background at various luminance levels in a randomized order. During the MEG recording, participants were instructed to rate the brightness of the disk (magnitude estimation) and to report it aloud during inter-stimulus interval. The MEG results showed that the neuromagnetic activation around 200-220 ms after the stimulus onset in the left occipito-temporal regions at a given trial was weaker when the disk luminance in the immediately prior trial was higher. An inverse inter-trial effect was also observed in the psychophysical experiment. These findings suggest that the neuromagnetic activity reflects the inter-trial modulation of luminance processing that correlates with the subjective perception of brightness.

En este estudio, se examinó si el procesamiento de iluminación en el sistema visual humano exhibie algún efecto de historia (es decir, modulación inter-ensayo) en experimentos psicofísicos y de magnetoencefalografía (MEG). Un disco se presentó contra un fondo negro en varios niveles de iluminación en un orden aleatorio. Durante el registro de MEG, los participantes fueron instruidos para clasificar el brillo del disco (estimación de magnitud) y reportarlo durante el intervalo inter-ensayo. Los resultados de MEG mostraron que la activación neuromagnetica alrededor 200-220 ms después de la aparición de estímulo en las regiones occipito-temporal izquierda en un ensayo dade fue más débil cuando la iluminación de disco en el ensayo inmediatamente antes fue mayor. También se observó un efecto inverso inter-ensayo en el experimento psicofísico. Estos hallazgos sugieren que la actividad neuromagnética refleja la modulación inter-ensayo de procesamiento de iluminación que se correlaciona con la percepción subjetiva de brillo.

Longitudinal measurements of luminance and chromatic contrast sensitivity: comparison between wavefront-guided LASIK and contralateral PRK for myopia / Medidas longitudinais da sensibilidade ao contraste de luminância e cromático: comparação entre wavefront-LASIK e wavefront-PRK para miopia

PURPOSE: The present study aimed to compare the postoperative contrast sensitivity functions between wavefront-guided LASIK eyes and their contralateral wavefront-guided PRK eyes. METHODS: The participants were 11 healthy subjects (mean age=32.4 ± 6.2 years) who had myopic astigmatism. The spatial contrast sensitivity functions were measured before and three times after the surgery. Psycho and a Cambridge graphic board (VSG 2/4) were used to measure luminance, red-green, and blue-yellow spatial contrast sensitivity functions (from 0.85 to 13.1 cycles/degree). Longitudinal analysis and comparison between surgeries were performed. RESULTS: There was no significant contrast sensitivity change during the one-year follow-up measurements neither for LASIK nor for PRK eyes. The comparison between procedures showed no differences at 12 months postoperative. CONCLUSIONS: The present data showed similar contrast sensitivities during one-year follow-up of wave-front guided refractive surgeries. Moreover, one year postoperative data showed no differences in the effects of either wavefront-guided LASIK or wavefront-guided PRK on the luminance and chromatic spatial contrast sensitivity functions.

OBJETIVO: A proposta do presente estudo é comparar funções de sensibilidade ao contraste obtidas após wavefront-LASIK e wavefront-PRK no olho contralateral. MÉTODOS: Os participantes foram 11 sujeitos saudáveis (idade média=32,4 ± 6,2 anos) com astigmatismo miópico. As funções de sensibilidade ao contraste espacial foram obtidas antes e três vezes após a cirurgia. O programa Psycho e uma placa gráfica da Cambridge Research Systems (VSG 2/4) permitiram gerar os estímulos com contraste espacial de luminância e cromático (verde-vermelho e azul-amarelo) de 0,85 até 13,1 ciclos/grau. Análises longitudinais e comparações entre as cirurgias foram realizadas. RESULTADOS: Não houve mudança significativa da sensibilidade ao contraste durante o primeiro ano após a cirurgia para o olho que recebeu o LASIK ou para o olho que recebeu o PRK. A comparação entre as cirurgias também foi semelhante no pós-operatório de um ano. CONCLUSÕES: Os resultados apresentados mostraram sensibilidade ao contraste semelhante durante o primeiro ano após a cirurgia refrativa com o wavefront. Além disso, no pós-operatório de um ano não houve diferença nas funções de sensibilidade ao contraste de luminância e cromático entre os olhos que receberam LASIK e os que receberam PRK.

Controle de qualidade de monitores de diagnóstico por imagem e iluminância nos espaços de pós-processamento em serviços de imagiologia / Display quality control based on luminance measurements in post-processing units at imaging diagnosis centers

OBJETIVO: Avaliar a qualidade dos monitores de diagnóstico e tratamento de imagem digital em radiologia convencional (raios X) com base nos níveis de luminância. Fez-se a medição da iluminância dos postos de trabalho onde estavam os monitores. MATERIAIS E MÉTODOS: A medição da luminância foi realizada usando-se um detector Unfors Xi Light em cinco instituições, com 23 monitores primários e 22 secundários, sendo 6 usados em urgência, seguindo o método descrito no relatório TG18 da American Association of Physicists in Medicine (AAPM). O instrumento de medida utilizado foi o Delta Ohm HD 9221 luximeter. RESULTADOS: Para as recomendações da AAPM, tanto monitores primários como secundários cumpriram, no geral, os níveis de tolerância. No caso dos níveis de iluminância, nos locais de trabalho dos monitores primários encontravam-se ligeiramente acima do intervalo recomendado. Quanto às recomendações do The Royal College of Radiologists (RCR), os monitores que respeitaram os níveis recomendados estavam em minoria, embora as diferenças não fossem significativas. CONCLUSÃO: Em geral, os resultados foram satisfatórios, embora os monitores não fossem adequados para atingir as recomendações exigentes do RCR. Os níveis de referência entre os monitores primários e secundários deveriam aproximar-se, de modo a garantir a qualidade de imagem. Os monitores para visualização e diagnóstico de imagens médicas devem ser regularmente avaliados para manter um sistema com a qualidade exigida, dada a função que desempenham.

OBJECTIVE: To evaluate the quality of primary and secondary displays of conventional radiography systems based on luminance measurements. The level of ambient lighting within the rooms was also measured. MATERIALS AND METHODS: Luminance measurements were performed with an Unfors Xi Light Detector in 23 primary and 22 secondary displays (six of them utilized in emergency departments) at five different institutions, and according to the method described on the American Association of Physicists in Medicine (AAPM) TG18 report. The level of ambient lighting was measured with Delta Ohm HD 9221 lux meter. RESULTS: In general, both the primary and secondary the displays were compliant with the AAPM guidelines. As regards ambient lighting, the primary workstation rooms were slightly above the recommended levels. As far as The Royal College of Radiologists (RCR) recommendations are concerned, the number of compliant displays corresponded to a minority, with no significant difference, though. CONCLUSION: Although most of the displays could not meet the strict RCR guidelines, in general, the results were satisfactory. The level of agreement between primary and secondary displays should be as high as possible in order to guarantee the image quality. Considering the key role played by diagnostic imaging systems, medical imaging displays must be regularly evaluated to assure that the quality of the imaging system is maintained.

Sensibilidade ao contraste espacial de adultos jovens para grades senoidais verticais em condições diferentes de luminância / Spatial contrast sensitivity of young adults for vertical sine-wave gratings in different conditions of luminance / La sensibilidad al contraste espacial de los adultos jóvenes a la verticales redes sinusoidales en condiciones diferentes de luminancia

O objetivo deste estudo foi medir a função de sensibilidade ao contraste (FSC) de adultos jovens para frequências espaciais de grades senoidais verticais em condições de luminância fotópica e escotópica. Utilizou-se o método psicofísico da escolha forçada para estimativa da sensibilidade ao contraste para as frequências de 0,6, 2,5 e 5,0 cpg. Todos os participantes apresentavam acuidade visual normal ou corrigida e estavam livres de doenças oculares identificáveis. As análises estatísticas mostraram que houve diferenças entre as condições de luminância e que os adultos foram mais sensíveis às frequências média e alta na condição de luminância fotópica. Esses resultados indicam que as características do sistema visual humano para detectar frequências espaciais em condições de luminância fotópica e escotópica passam por mecanismos distintos que tornam possível a diferenciação de contraste.

The aim of this study was to measure the contrast sensitivity function (CSF) of young adults for spatial frequencies of vertical sine-wave gratings in terms of photopic and scotopic luminance. We used the forced-choice psychophysical method to estimate contrast sensitivity for frequencies of 0.6, 2.5 and 5.0 cpd. All participants had normal or corrected acuity and they were free of ocular pathologies. Statistical analysis showed that there were differences between the conditions of luminance, where adults were more sensitive to middle and high frequencies in the photopic luminance condition. These results indicate that the characteristics of human visual system to detect spatial frequencies in photopic conditions of luminance and scotopic pass through distinct mechanisms that make possible the differentiation of contrast.

El objetivo de este estudio fue medir la función de sensibilidad al contraste (FSC) de los adultos jóvenes para frecuencias espaciales de las verticales redes sinusoidales en condiciones de luminosidad fotópica y escotópica. Se utilizó el método psicofísico de elección forzada para estimar la sensibilidad al contraste para las frecuencias de 0,6, 2,5 y 5,0 cpg. Todos los participantes presentaban acuidad visual normal o corigida y estaban libres de patología ocular. El análisis estadístico mostró que hay diferencias entre las condiciones de luminancia, y que los adultos son más sensibles a las frecuencias medias y altas en la condición de luminancia fotópica. Estos resultados indican que las características del sistema visual humano para la detección de frecuencias espaciales en condiciones de luminancia fotópica y escotópica pasan por diferentes mecanismos que hacen posible la diferenciación de contraste.

Efeito do ambiente de produção sobre frangos de corte sexados criados em galpão comercial / Effect of the production environment on sexed broilers reared in a commercial house

Avaliou-se o efeito do ambiente de produção sobre o desempenho produtivo e respostas fisiológicas de frangos de corte demarca comercial sexados, machos e fêmeas. Os frangos foram criados em duas alas separadas no interior de um galpão comercial com sistemas de ventilação convencional e nebulização. O ambiente produtivo foi avaliado por meio do índice de temperatura do globo negro e umidade, da intensidade de ruído e do nível de iluminância. A avaliação dos animais foi feita por meio das respostas fisiológicas - frequência respiratória, temperatura retal, temperatura da pele e temperatura da pena - e produtivas - ganho de peso semanal, massa corporal e mortalidade. Os machos apresentaram desempenho produtivo superior às fêmeas (P<0,05). A massa corporal média dos machos foi 214,6g maior que a das fêmeas aos 35 dias de vida, a qual se igualou à massa corporal dos machos somente aos 38,47 dias de vida. As respostas fisiológicas não se relacionaram com o ambiente.

The effect of the production environment on the productive performance and physiological responses of sexed broiler chickens, male and female, was evaluated. The birds were raised in two separate regions inside the broiler house. The productive environment was determined using the black-globe temperature humidity index, as well as noise and luminance levels. The physiological responses (breath rate, rectal temperature, skin temperature and feather temperature) and productive responses (weekly weight gain, body mass and mortality) were used to evaluate the effect of the production environment on the broilers raised in a house equipped with conventional and misting ventilation systems. The mean body mass of the males was 214.6 g greater than females at 35 days of life, which became equal to the male mean body mass only at 38.47 days of life. The physiological responses were not related to the environment.

An experimental study regarding diagnostic accuracy on image interpretation of the digital image film by using viewboxes of different luminance / 中华放射学杂志

Objective To evaluate diagnostic accuracy of image interpretation using viewboxes at different luminance with ALVIM statistical phantom (TRG).Methods A digital film of TRG image was obtained by exposing the phantom of TRG with Kodak DR 3000 using proper parameter.Viewboxes with three different luminance were selected from those used in daily work.The film of TRG was evaluated with these viewboxes of three different luminance by three different radiologists with experience of five,eight and sixteen years respectively.A grade scale of 5 was used to evaluate each row of signal and noise.According to the results and formula,the probabilities of true-positive [P (S/s)],false-positive [P (S/n)] and true answer(Pdet) were obtained. Results The three kinds of luminance used in viewboxes were: (3489 ± 256),(2231 ± 220),(816 ± 168) cd/m2.When the average luminance of viewbox was 3489 cd/m2,Pdet of 0.6,0.7,0.8 mm in bone substitute was 0.558±0.009,0.788±0.008,0.813±0.006,Pdet of0.9,1.0,1.2 mm in muscle substitute was 0.663 ± 0.010,0.750 ± 0.008,0.933 ± 0.005 ; When the average luminance of viewbox was 2231 cd/m2 ,Pdet of 0.6,0.7,0.8 mm in bone substitute was 0.525 ± 0.013,0.713 ± 0.013,0.775 ± 0.016,Pdet of 0.9,1.0,1.2 mm in muscle substitute was 0.613 ± 0.019,0.650 ± 0.013,0.850±0.019 ;When the average luminance of viewbox was 816 cd/m2 ,Pdet of 0.6,0.7,0.8 mm in bone substitute was 0.475 ± 0.022,0.550 ± 0.018,0.688±0.020,Pdet of 0.9,1.0,1.2 mm in muscle substitute was 0.550 ± 0.025,0.575 ± 0.021,0.725 ± 0.016. Viewboxes of different luminance were compared to one another by paired t-test.The results of comparison all had significant statistical differences (t = 5.057 and 4.681 ,P <0.05).Conclusions The image displayed by viewboxes at different luminance had significant influence on image interpretation. The higher the luminace of viewbox,the richer the information displayed,and the higher the accuracy of diagnosis.

Binocular Luminance Summantion in Estoropic and Exotropic Kittens

Nomal kittens showed a gradual increase from 17.6% to 25.5% of BLS with aging from the fifth week to the ninth. Young kittens showed significantly less BLS than adult ones(p<0.1). There was no significant difference in BLS between exotropic and nomal kittens or alternating and non-alternating strabismic ones. However, there was a significant difference in BLS between esotropic and nomal ones(p<0.1). These results suggested that the BLS can be used as an index for the extent of total field from both eyes.

Binocular luminance summation (BLS) in esotropic and exotropic kittens

Normal kittens showed a gradual increase from 17.6% to 25.5% of BLS with aging from the fifth week to the ninth. Young kittens showed significantly less BLS than do adult ones (p < 0.1), There was significant difference of BLS between exotropic and normal kittens or alternating and non-alternating strabismic ones. However, there was a significant diftrence between esotropic and normal ones (p < 0.1). These results suggested that the BLS can be used as a index for the extent of total field from both eyes.