A passive, camera-based head-tracking system for real-time, three-dimensional estimation of head position and orientation in rodents.

Tracking head position and orientation in small mammals is crucial for many applications in the field of behavioral neurophysiology, from the study of spatial navigation to the investigation of active sensing and perceptual representations. Many approaches to head tracking exist, but most of them only estimate the 2D coordinates of the head over the plane where the animal navigates. Full reconstruction of the pose of the head in 3D is much more more challenging and has been achieved only in handful of studies, which employed headsets made of multiple LEDs or inertial units. However, these assemblies are rather bulky and need to be powered to operate, which prevents their application in wireless experiments and in the small enclosures often used in perceptual studies. Here we propose an alternative approach, based on passively imaging a lightweight, compact, 3D structure, painted with a pattern of black dots over a white background. By applying a cascade of feature extraction algorithms that progressively refine the detection of the dots and reconstruct their geometry, we developed a tracking method that is highly precise and accurate, as assessed through a battery of validation measurements. We show that this method can be used to study how a rat samples sensory stimuli during a perceptual discrimination task and how a hippocampal place cell represents head position over extremely small spatial scales. Given its minimal encumbrance and wireless nature, our method could be ideal for high-throughput applications, where tens of animals need to be simultaneously and continuously tracked.NEW & NOTEWORTHY Head tracking is crucial in many behavioral neurophysiology studies. Yet reconstruction of the head's pose in 3D is challenging and typically requires implanting bulky, electrically powered headsets that prevent wireless experiments and are hard to employ in operant boxes. Here we propose an alternative approach, based on passively imaging a compact, 3D dot pattern that, once implanted over the head of a rodent, allows estimating the pose of its head with high precision and accuracy.

Accuracy of Rats in Discriminating Visual Objects Is Explained by the Complexity of Their Perceptual Strategy.

Despite their growing popularity as models of visual functions, it remains unclear whether rodents are capable of deploying advanced shape-processing strategies when engaged in visual object recognition. In rats, for instance, pattern vision has been reported to range from mere detection of overall object luminance to view-invariant processing of discriminative shape features. Here we sought to clarify how refined object vision is in rodents, and how variable the complexity of their visual processing strategy is across individuals. To this aim, we measured how well rats could discriminate a reference object from 11 distractors, which spanned a spectrum of image-level similarity to the reference. We also presented the animals with random variations of the reference, and processed their responses to these stimuli to derive subject-specific models of rat perceptual choices. Our models successfully captured the highly variable discrimination performance observed across subjects and object conditions. In particular, they revealed that the animals that succeeded with the most challenging distractors were those that integrated the wider variety of discriminative features into their perceptual strategies. Critically, these strategies were largely preserved when the rats were required to discriminate outlined and scaled versions of the stimuli, thus showing that rat object vision can be characterized as a transformation-tolerant, feature-based filtering process. Overall, these findings indicate that rats are capable of advanced processing of shape information, and point to the rodents as powerful models for investigating the neuronal underpinnings of visual object recognition and other high-level visual functions.

O gênero masculino e os cuidados de saúde: a experiência de homens de um centro de saúde / The male genre and health care: the experience of men at a health center

Compreender como os homens de um Centro de Saúde se comportam quanto aos cuidados com a saúde. Estudo qualitativo, realizado em um Centro de Saúde Escola que selecionou por conveniência e entrevistou 15 indivíduos do gênero masculino, adultos e organizou os dados conforme o Discurso do Sujeito Coletivo. Emergiram quatro ideias centrais que retratam os motivos para procurar o serviço, problemas de saúde, atitudes diante desses problemas e participação nas atividades da unidade. Esses indivíduos são assíduos, se preocupam em seguir as recomendações recebidas e utilizam o atendimento individual, preferencialmente, por falta de tempo, mas demonstram interesse em participar de atividades em grupo. Isto deve ser utilizado pelo serviço como oportunidade de intensificar a participação deles em grupo específico já existente para homens, que oferece um espaço de acolhimento e escuta de problemas diversos, sendo uma forma de reintegração desses indivíduos junto ao serviço de saúde...

Diarréia nosocomial: aspectos epidemiológicos de um problema emergente / Nosocomial diarrhea: epidemiological aspects of an emerging problem

Diarréia nosocomial (DN) é um problema comum em hospitais em todo o mundo, com causas e consequências pouco documentadas. As características säo o aparecimento de diarréia após 72 horas de internaçäo, com mais de 2 evacuaçöes de fezes aquosas ou amolecidas por no mínimo dois dias. Objetivos:Verificar a incidência de DN e seus fatores predisponentes. Paciente e métodos: Em um estudo prospectivo entre julho de 1997 e julho de 1998, 656 pacientes internados no Hospital Universitário da Universidade Federal de Juiz de Fora, foram analisados através de um interrogatório padronizado diário. Resultados: 348 (53 por cento) eram homens e 460 (70 por cento) brancos. A média de idade era de 50,3 anos (13 a 94 anos) e tempo médio de internaçäo foi de 13 dias (4 a 41 dias). DN foi observada em 17 pacientes (2,6 por cento), com duraçäo média de 13 dias. O uso de sonda nasogástrica, nutriçäo enteral ou parenteral, bloqueadores dos receptores H-2 da histamina e presença de diarréia em contactantes mostrou relaçäo estatisticamente significante com a ocorrência de DN (p<0,05). A doença que causou a hospitalizaçäo, o uso de antibióticos e procedimentos cirúrgicos näo se correlacionaram com a DN. Entretanto, quanto maior a permanência hospitalar (particularmente após 10 dias), maior a probabilidade de sua ocorrência. Dos 18 com DN, 8 estavam internados no CTI. Conclusäo: A incidência de diarréia nosocomial (2,6 por cento) aproxima-se da relatada na literatura. Um risco aumentado é relacionado à permanência hospitalar prolongada, ao uso de sonda nasogástrica, à dieta enteral ou parenteral, ao uso de bloqueadores dos receptores H-2 da histamina e à presença de diarréia em contactantes.