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Search Results: 1 - 10 of 795 matches for " Caio Maximino "
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Evolutionary Changes in the Complexity of the Tectum of Nontetrapods: A Cladistic Approach
Caio Maximino
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003582
Abstract: Background The tectum is a structure localized in the roof of the midbrain in vertebrates, and is taken to be highly conserved in evolution. The present article assessed three hypotheses concerning the evolution of lamination and citoarchitecture of the tectum of nontetrapod animals: 1) There is a significant degree of phylogenetic inertia in both traits studied (number of cellular layers and number of cell classes in tectum); 2) Both traits are positively correlated accross evolution after correction for phylogeny; and 3) Different developmental pathways should generate different patterns of lamination and cytoarchitecture. Methodology/Principal Findings The hypotheses were tested using analytical-computational tools for phylogenetic hypothesis testing. Both traits presented a considerably large phylogenetic signal and were positively associated. However, no difference was found between two clades classified as per the general developmental pathways of their brains. Conclusions/Significance The evidence amassed points to more variation in the tectum than would be expected by phylogeny in three species from the taxa analysed; this variation is not better explained by differences in the main course of development, as would be predicted by the developmental clade hypothesis. Those findings shed new light on the evolution of an functionally important structure in nontetrapods, the most basal radiations of vertebrates.
Modulation of nociceptive-like behavior in zebrafish (Danio rerio) by environmental stressors
Maximino, Caio;
Psychology & Neuroscience , 2011, DOI: 10.3922/j.psns.2011.1.017
Abstract: zebrafish have been demonstrated to react consistently to noxious chemical stimuli and present reliable phenotypes of stress, fear, and anxiety. in this article, we describe the modulation of nociceptive-like responses of zebrafish to fear-, stress-, and anxiety-eliciting situations. animals were exposed to an alarm substance, confinement stress, or a novel environment before being injected with 1% acetic acid in the tail. the alarm substance and confinement stress reduced the display of erratic movements and tail-beating behavior elicited by acetic acid. the novelty of the environment, in contrast, increased the frequency of tail-beating behavior. the results suggest that descending modulatory control of nociception exists in zebrafish, with apparent fear- and stress-induced analgesia and anxiety-induced hyperalgesia.
Modulation of nociceptive-like behavior in zebrafsh (Danio rerio) by environmental stressors
Caio Maximino
Psychology & Neuroscience , 2011,
Abstract: Zebrafsh have been demonstrated to react consistently to noxious chemical stimuli and present reliable phenotypes of stress, fear, and anxiety. In this article, we describe the modulation of nociceptive-like responses of zebrafsh to fear-, stress-, and anxiety-eliciting situations. Animals were exposed to an alarm substance, confnement stress, or a novel environment before being injected with 1% acetic acid in the tail. The alarm substance and confnement stress reduced the display of erratic movements and tail-beating behavior elicited by acetic acid. The novelty of the environment, in contrast, increased the frequency of tail-beating behavior. The results suggest that descending modulatory control of nociception exists in zebrafsh, with apparent fear- and stress-induced analgesia and anxiety-induced hyperalgesia.
Pluralidade racial: um novo desafio para a psicologia
Caio Maximino de Oliveira
Psicologia: Ciência e Profiss?o , 2002, DOI: 10.1590/s1414-98932002000400005
Abstract: Esse artigo tem por objetivo analisar os elementos que constituem o racismo e a discrimina o por meio de uma perspectiva psicossocial, demonstrando as raízes culturais das manifesta es de preconceito e sua origem no mito do bode expiatório. Visa mostrar a nossa imers o quase completa na ideologia dominante, jogando principalmente com os conceitos de imaginário social, ideologia, hegemonia e autoridade e sua constru o social. Apresenta um ponto de vista anti-autoritário e por meio deles, demonstra o desafio da Psicologia em se livrar dos grilh es impostos pela ideologia dominante que a impedem de ser ciência n o comprometida com as classes dominantes. This paper aims to determine the causes of racism and discrimination through a psychosocial perspective, demonstrating the cultural roots of prejudiced manifestations and its origins in the myth of the scapegoat. The objective is, thus, to show our almost complete immersion in the dominant ideology, dealing mainly with the concepts of social imaginary, ideology, hegemony and authority and its historical construction. An anti-authoritarian point of view is placed. Through it, Psychology's challenge in getting rid of its manacles, imposed by the dominant ideology, that hinders it from being a science not involved with the dominant classes.
Construct validity of behavioral models of anxiety: where experimental psychopathology meets ecology and evolution
Maximino, Caio;Brito, Thiago Marques de;Gouveia Jr, Amauri;
Psychology & Neuroscience , 2010, DOI: 10.3922/j.psns.2010.1.015
Abstract: in experimental psychopathology, construct validity is usually enhanced by addressing theories from other fields in its nomological network. in the field of anxiety research, this construct is related to antipredator behavior, conserved across phylogeny in its functions and neural basis, but not necessarily on its topography. even though the relations between behavioral models of anxiety and statements from behavioral ecology and evolutionary biology are commonly made in anxiety research, these are rarely tested, at least explicitly. however, in order to increase construct validity in experimental anxiety, testing predictions from those theories is highly desirable. this article discusses these questions, suggesting a few ways in which behavioral ecological and evolutionary hypotheses of anxiety-like behavior may be tested.
The effects of diazepam on the elevated T-maze are dependent on the estrous cycle of rats
Gouveia Jr, Amauri;Antunes, Gabriela;Maximino, Caio;Morato, Silvio;
Psychology & Neuroscience , 2009, DOI: 10.3922/j.psns.2009.2.016
Abstract: in order to determine the modulation of anxiolytic and panicolytic-like effects of diazepam by the hormonal cycle of female rats, male and female rats - the latter divided per estrous cycle phase (estrus, diestrus, metaestrus and proestrus) - were tested in the elevated t-maze, a behavioral model of panic and anxiety. diazepam (0.5, 1.0 and 2.0 mg/kg) or saline solution was injected in individual animals that were submitted to one session in the elevated t-maze 25 min after drug/saline administration. the test consisted of three avoidance trials and one escape trial, separated by a 30 s interval, during which the animals were isolated in individual cages. the avoidance trials began with the animal being placed at the end of the maze's enclosed arm. the time necessary for the animal to leave the central square was considered as the response's latency. the trials that exceeded 300 s were considered as failures. results demonstrate a decrease in the effects of diazepam in inhibitory avoidance (anxiety) trials in females in diestrus and proestrus, but no relation of gender or estrous cycle on diazepam effects on escape trials (fear). the results support the hypothesis that down-regulation of gabaa receptors by activation of nuclear estrogen receptors and induction of pkc-mediated gabaa receptor phosphorylation by activation of surface estrogen receptors in raphe neurons underlie the modulation of diazepam sensitivity by estrogen.
Construct validity of behavioral models of anxiety: where experimental psychopathology meets ecology and evolution.
Caio Maximino,Thiago Marques de Brito,Amauri Gouveia Jr
Psychology & Neuroscience , 2010,
Abstract: In experimental psychopathology, construct validity is usually enhanced by addressing theories from other fields in its nomological network. In the field of anxiety research, this construct is related to antipredator behavior, conserved across phylogeny in its functions and neural basis, but not necessarily on its topography. Even though the relations between behavioral models of anxiety and statements from behavioral ecology and evolutionary biology are commonly made in anxiety research, these are rarely tested, at least explicitly. However, in order to increase construct validity in experimental anxiety, testing predictions from those theories is highly desirable. This article discusses these questions, suggesting a few ways in which behavioral ecological and evolutionary hypotheses of anxiety-like behavior may be tested.
THE EFFECTS OF DIAZEPAM ON THE ELEVATED T-MAZE ARE DEPENDED ON THE ESTROUS CYCLE OF RATS
Amauri Gouveia Jr, Gabriela Antunes, Caio Maximino, Silvio Morato
Psychology & Neuroscience , 2009,
Abstract: In order to determine the modulation of anxiolytic and panicolytic effects of diazepam by the hormonal cycle of female rats, male and female rats – the latter divided per estrous cycle phase (estrus, diestrus, metaestrus and proestrus) – were tested in the elevated T-maze, a behavioral model of panic and anxiety. Diazepam (0.5, 1.0 and 2.0 mg/kg) or saline solution was injected in individual animals that were submitted to one session in the elevated T-maze 25 min after drug/saline administration. The test consisted of three avoidance trials and one escape trial, separated by a 30 s interval, during which the animals were isolated in individual cages. The avoidance trials began with the animal being placed at the end of the maze's enclosed arm. The time necessary for the animal to leave the central square was considered as the response's latency. The trials that exceeded 300 s were considered as failures. Results demonstrate a decrease in the effects of diazepam in inhibitory avoidance (anxiety) trials in females in diestrus and proestrus, but no relation of gender or estrous cycle on diazepam effects on escape trials (fear). The results support the hypothesis of down-regulation of GABAA receptors by activation of nuclear estrogen receptors and induction of PKC-mediated GABAA receptor phosphorylation by activation of surface estrogen receptors in raphe neurons underlie the modulation of diazepam sensitivity by estrogen.
Influence of gender and estrous cycle in the forced swim test in rats
Gouveia Jr., Amauri;Afonseca, Taciana Lucas;Maximino, Caio;Dominguez, Roberto;Morato, Silvio;
Psychology & Neuroscience , 2008, DOI: 10.3922/j.psns.2008.2.012
Abstract: the present work aimed at studying the influence of the estrous cycle in the forced swim test, an animal model of depression. for this, 44 male and female wistar rats were divided into five groups according to the hormonal state in the first day of the study: metaestrus (n = 12), diestrus (n = 8), proestrus (n = 7), estrous (n = 6) and males (n = 11). they were housed in groups of five, with water and food ad libitum under a 12/12 h light/dark cycle. females were screened daily for the estrous cycle. the animals were subjected to two swimming sessions in a glass cylinder with water up to 15 cm at 28±2o c. the data of the first five minutes of a 15-min first session were compared to those of a 5-min second session 24 h later. the results indicate that the latency to the first immobility was substantially reduced in the second session and was longer for females in diestrus and proestrus in the first session. the results also indicate that females in diestrus and proestrus exhibited less immobility than males in the first session; females in diestrus also exhibited less immobility than females in metaestrus. females in metaestrus and diestrus, as well as males, did not present the decrease in total immobility times in the second session. the present results are analyzed in terms of differential effects of progesterone and estrogen on a learning component and an affective component.
Influence of gender and estrous cycle in the forced swim test in rats
Amauri Gouveia Jr., Taciana Lucas Afonseca, Caio Maximino, Roberto Dominguez and Silvio Morato
Psychology & Neuroscience , 2008,
Abstract: The present work aimed at studying the influence of the estrous cycle in the forced swim test, an animal model of depression. For this, 44 male and female Wistar rats were divided into five groups according to the hormonal state in the first day of the study: metaestrus (N = 12), diestrus (N = 8), proestrus (N = 7), estrous (N = 6) and males (N = 11). They were housed in groups of five, with water and food ad libitum under a 12/12 h light/dark cycle. Females were screened daily for the estrous cycle. The animals were subjected to two swimming sessions in a glass cylinder with water up to 15 cm at 28±2o C. The data of the first five minutes of a 15-min first session were compared to those of a 5-min second session 24 h later. The results indicate that the latency to the first immobility was substantially reduced in the second session and was longer for females in diestrus and proestrus in the first session. The results also indicate that females in diestrus and proestrus exhibited less immobility than males in the first session; females in diestrus also exhibited less immobility than females in metaestrus. Females in metaestrus and diestrus, as well as males, did not present the decrease in total immobility times in the second session. The present results are analyzed in terms of differential effects of progesterone and estrogen on a learning component and an affective component.
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