Clinical studies show that physical exercise has anxiolytic and pro-cognitive properties for both healthy individuals and psychiatric patients. Most of these data refer to the effects of aerobic exercise. However, other modalities such as resistance exercise deserve more attention because they may also modulate brain function. This study aimed to compare the effects of an aerobic exercise protocol on a treadmill and a resistance exercise protocol on a ladder apparatus on anxiety-like behavior, cognitive flexibility, and neuroplasticity parameters in healthy animals. Adult male Wistar rats were divided into three groups: sedentary control, aerobic training, and resistance training. Subsequently, they were evaluated in the elevated plus-maze (EPM), light-dark box, and modified hole board (mHB) tests. The expressions of synaptophysin and postsynaptic plasticity protein 95 in the dorsal and ventral hippocampus were analyzed by immunofluorescence. The results demonstrated an anxiolytic effect promoted by exercise in the EPM, particularly in the animals submitted to aerobic training, and a mild pro-learning effect of both exercise modalities was observed in the mHB test. All groups showed similar outcomes in the other evaluations. Therefore, the exercise modalities investigated in the present study did not provide considerable modifications to such aspects of the emotional/cognitive functions and neuroplasticity under physiological contexts. Perhaps the two types of exercise acted in neurobiological pathways not analyzed in this study, or the effects may emerge under pathological contexts. These hypotheses should be tested in future studies.

Neste trabalho apresentamos um experimento muito simples explorando a polarização de um feixe laser intenso para simular a distribuição de uma chave criptográfica através do protocolo BB84 de criptografia quântica. Nossa proposta está baseada na analogia entre graus de liberdade de um feixe laser com estados quânticos da luz, muito discutida atualmente. A proposta utiliza duas bases de polarização linear, que é o ingrediente original do protocolo proposto por Bennet e Brassard. Dessa forma, o experimento permite um entendimento direto do princípio de funcionamento do protocolo. O experimento pode ser realizado em laboratórios didáticos dos cursos de graduação em Física e Engenharias bem como em espaços de divulgação científica. Além disso, os resultados mostram que o experimento apresenta um ambiente muito propício para discussão sobre a diferença entre propriedades clássicas e quânticas da luz.

We present a very simple experiment exploring the polarization of an intense laser beam in order to perform an emulation of a cryptographic key distribution by the well known BB84 protocol. Our work relies on the analogy between classical degrees of freedom of a laser beam and quantum states, very discussed nowadays. Our analogue of a key distribution is made by using two polarization basis, the original ingredient used by Bennet and Brassard, which allow us a direct understanding of the protocol. The experiment can be performed in didactic laboratories or can be demonstrated in a classroom. In addition, the results show a very proper ambient to discuss the difference between classical and quantum measurement of light.

Permanent bilateral occlusion of the common carotid arteries (2VO) in the rat has been established as a valid experimental model to investigate the effects of chronic cerebral hypoperfusion on cognitive function and neurodegenerative processes. Our aim was to compare the cognitive and morphological outcomes following the standard 2VO procedure, in which there is concomitant artery ligation, with those of a modified protocol, with a 1-week interval between artery occlusions to avoid an abrupt reduction of cerebral blood flow, as assessed by animal performance in the water maze and damage extension to the hippocampus and striatum. Male Wistar rats (N = 47) aged 3 months were subjected to chronic hypoperfusion by permanent bilateral ligation of the common carotid arteries using either the standard or the modified protocol, with the right carotid being the first to be occluded. Three months after the surgical procedure, rat performance in the water maze was assessed to investigate long-term effects on spatial learning and memory and their brains were processed in order to estimate hippocampal volume and striatal area. Both groups of hypoperfused rats showed deficits in reference (F(8,172) = 7.0951, P < 0.00001) and working spatial memory [2nd (F(2,44) = 7.6884, P < 0.001), 3rd (F(2,44) = 21.481, P < 0.00001) and 4th trials (F(2,44) = 28.620, P < 0.0001)]; however, no evidence of tissue atrophy was found in the brain structures studied. Despite similar behavioral and morphological outcomes, the rats submitted to the modified protocol showed a significant increase in survival rate, during the 3 months of the experiment (P < 0.02).