Selective Coupling between Theta Phase and Neocortical Fast Gamma Oscillations during REM-Sleep in Mice

TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

Encoding mechanisms based on fast oscillations in the retina of the cat and their dependencies on anesthesia

Processing in the visual system starts in the retina. Its complex network of cells with different properties enables for parallel encoding and transmission of visual information to the lateral geniculate nucleus (LGN) and to the cortex. In the retina, it has been shown that responses are often accompanied by fast synchronous oscillations (30 - 90 Hz) in a stimulus-dependent manner. Studies in the frog, rabbit, cat and monkey, have shown strong oscillatory responses to large stimuli which probably encode global stimulus properties, such as size and continuity (Neuenschwander and Singer, 1996; Ishikane et al., 2005). Moreover, simultaneous recordings from different levels in the visual system have demonstrated that the oscillatory patterning of retinal ganglion cell responses are transmitted to the cortex via the LGN (Castelo-Branco et al., 1998). Overall these results suggest that feedforward synchronous oscillations contribute to visual encoding. In the present study on the LGN of the anesthetized cat, we further investigate the role of retinal oscillations in visual processing by applying complex stimuli, such as natural visual scenes, light spots of varying size and contrast, and flickering checkerboards. This is a necessary step for understanding encoding mechanisms in more naturalistic conditions, as currently most data on retinal oscillations have been limited to simple, flashed and stationary stimuli. Correlation analysis of spiking responses confirmed previous results showing that oscillatory responses in the retina (observed here from the LGN responses) largely depend on the size and stationarity of the stimulus. For natural scenes (gray-level and binary movies) oscillations appeared only for brief moments probably when receptive fields were dominated by large continuous, flat-contrast surfaces. Moreover, oscillatory responses to a circle stimulus could be broken with an annular mask indicating that synchronization arises from relatively local interactions among populations of activated cells in the retina. A surprising finding in this study was that retinal oscillations are highly dependent on halothane anesthesia levels. In the absence of halothane, oscillatory activity vanished independent of the characteristics of the stimuli. The same results were obtained for isoflurane, which has similar pharmacological properties. These new and unexpected findings question whether feedfoward oscillations in the early visual system are simply due to an imbalance between excitation and inhibition in the retinal networks generated by the halogenated anesthetics. Further studies in awake behaving animals are necessary to extend these conclusions

As relações de gênero no trabalho: uma análise da inserção das mulheres e homens na rede de fast food

The purpose of this study was investigate the sexual division of the work in a chain of fast food, in Natal, RN. These aspects were analyzed with the ways of organization of the work, being made a case study. The main objective of this survey was to analyze the influence of gender relations in the insertion of men and women in the job market and to analyze the question of feminine submission in the professional world. These questions were analyzed considering the current period of the worldwide capitalism, from the characteristics of productive process and the growth of the service sectors. The research was made with a group of workers on the production sectors; attendance, management and human resources at restfood store, where six clerks were interviewed. Through our research, it is possible to perceive the permanence of the sexual division at the job in the interior of the productive processes at Restfood, that puts the woman in a subordinate position in relation to the man. This result can be confirmed if we considerate that the women, on this chain of food, occupy in first place the function of waitress and on this, trere s no functional progression, while her workmates (the men) for occupying other functions can progress inside the company. It was also evidenced that in a context of globalization of the capital, deregulation and disrespect of labor laws, the capital acts without any respect to workers. That was what we observed at the interviewer speech; the scarcity of the conditions of work and the constant disrespect of the labor laws. This way, we could evidence that the scarcity of work conditions hit men and women, but it has a crueler face with the women, and this one reproduces itself, day by day in the process of social reproduction, through family life, insertion in the world of the work, information and received social education. So, the capital explores all of them, but the gender relations create to the capital, the possibility of a different degree of exploration, becoming this way, the women main victims herself