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RESUMO O estudo do sistema nervoso e suas funções é fascinante e complexo. Um dos mais intrigantes assuntos deste campo é como a neurobiologia produz estados conscientes, o notório problema da consciência (cérebro e mente). Para esse estudo, são necessários conhecimentos tanto de neuroanatomia e fisiologia como de questões linguísticas e filosóficas, o que torna o assunto temido ou ignorado pelos estudantes de Medicina. Assim, aquele que vai iniciar o estudo desse capítulo da neurociência se depara com um questionamento: por onde começar? A quantidade de informação é muito grande, e o ponto de partida, em geral, pode ser a biologia, a psicologia ou a filosofia. Portanto, este ensaio tem como objetivo sugerir um caminho, entre vários possíveis, para nortear aqueles que desejam informações preliminares sobre o tema. Isto porque alguns estudantes têm dificuldade com o assunto por não dominarem alguns conceitos fundamentais ou desconhecerem as teorias defendidas, fixando-se apenas na vertente biológica do assunto. Desta maneira, na introdução deste manuscrito são apresentadas três possibilidades conceituais para a palavra consciência e alguns problemas de limitação do idioma. Na sequência, a neurobiologia é abordada de forma sucinta, com ênfase na atividade eletroquímica neuronal. Em seguida, são relatadas as teorias sobre a consciência e os pontos de vista de dois autores: David Chalmers e Daniel Dennett. A escolha desses autores para este trabalho visa demonstrar que tais teorias possuem movimento pendular: iniciando com Descartes e sua teoria dualista em um extremo, passando por outras teorias intermediárias e chegando até os materialistas reducionistas no extremo oposto. A metodologia se resume à pesquisa de artigos científicos sobre o tema. Por fim, embora a corrente majoritária defenda que a consciência é um fenômeno bioquímico, pois, para haver consciência é necessário cérebro, também há aqueles que defendem que a consciência não seja um atributo da matéria. Discussões como esta devem ser encorajadas e embasadas em fundamentação teórica.
ABSTRACT The study of the nervous system and its functions is fascinating and complex. One of the most intriguing in this field is how neurobiology produces conscious states; the notorious problem of consciousness (the brain and mind). For this study, a knowledge of both neuroanatomy and physiology is required, as well as of linguistic and philosophical issues. For this reason, this is a topic that is feared or avoided by medical students. The student wishing to begin this chapter of neuroscience faces a question: where to start? There is a vast amount of information on the subject, and the starting point, in general, can be biology, psychology or philosophy. This essay suggests one of several possible means of guiding those seeking preliminary information on the subject. Some students have difficulty with the subject because they lack the fundamental concepts needed, or they do not know the theories defended, but are focused on subject from a purely biological perspective. This work begins by presenting three conceptual possibilities for the word 'conscience', and some language limitations related to it. Next, it gives a succinct overview of neurobiology, with emphasis on neuronal electrochemical activity. The theories of consciousness are outlined, giving the points of view of two authors: David Chalmers and Daniel Dennett. This choice of authors demonstrates that such theories have pendular movement: starting with Descartes and his dualist theory at one extreme, passing through other intermediate theories, and reaching the reductionist materialists at the opposite extreme. The methodology consists of a literature search of scientific articles on the subject. Finally, although the majority argue that consciousness is a biochemical phenomenon, because in order to have consciousness there must be a brain, there are also those who argue that consciousness is not an attribute of matter. Discussions like these should be encouraged, and based on theoretical studies.
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ABSTRACT Neurophobia is a term used to describe a combination of negative reactions observed among students when faced with theoretical concept of neurosciences. It is driven by the belief that this subject matter is excessively abstract and complex, and something of an "eccentric branch" of medicine. The small number of professionals who display an interest in this specialty may be related to a rejection of the subject since their university days. The author attributes the perpetuation of neurophobia to two main factors: the fragmented way in which neuroscience is presented in the basic syllabus and the lack of a proactive attitude among some teachers to bring down the barriers that separate their knowledge from that of their students. In conclusion, proposals for overcoming neurophobia are suggested, which include presenting neurosciences in a more contextualized manner since the start of medical education and teachers adopting a more integrative posture in building bridges to connect new concepts to preexisting knowledge.
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The delimitation of the invasive moss species Campylopus introflexus from its closest relative, Campylopus pilifer, has been long debated based on morphology. Previous molecular phylogenetic reconstructions based on the nuclear ribosomal internal transcribed spacers (ITS) 1 and 2 showed that C. pilifer is split into an Old World and a New World lineage, but remained partly inconclusive concerning the relationships between these two clades and C. introflexus. Analyses of an extended ITS dataset displayed statistically supported incongruence between ITS1 and ITS2. ITS1 separates the New World clade of C. pilifer from a clade comprising C. introflexus and the Old World C. pilifer. Ancestral state reconstruction showed that this topology is morphologically supported by differences in the height of the dorsal costal lamellae in leaf cross-section (despite some overlap). ITS2, in contrast, supports the current morphological species concept, i.e., separating C. introflexus from C. pilifer, which is morphologically supported by the orientation of the hyaline hair point at leaf apex as well as costal lamellae height. Re-analysis of published and newly generated plastid atpB-rbcL spacer sequences supported the three ITS lineages. Ecological niche modeling proved a useful approach and showed that all three molecular lineages occupy distinct environmental spaces that are similar, but undoubtedly not equivalent. In line with the ITS1 topology, the C. pilifer lineage from the New World occupies the most distinct environmental niche, whereas the niches of Old World C. pilifer and C. introflexus are very similar. Taking the inferences from ecological niche comparisons, phylogenetics, and morphology together, we conclude that all three molecular lineages represent different taxa that should be recognized as independent species, viz. C. introflexus, C. pilifer (Old World clade), and the reinstated C. lamellatus Mont. (New World clade).
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This is the report of a rare case of endomyocardial fibrosis associated with massive calcification of the left ventricle in a male patient with dyspnea on great exertion, which began 5 years earlier and rapidly evolved. Due to lack of information and the absence of clinical signs that could characterize impairment of other organs, the case was initially managed as a disease with a pulmonary origin. With the evolution of the disease and in the presence of radiological images of heterogeneous opacification in the projection of the left ventricle, the diagnostic hypothesis of endomyocardial disease was established. This hypothesis was later confirmed on chest computed tomography. The patient died on the 16th day of the hospital stay, probably because of lack of myocardial reserve, with clinical findings of refractory heart failure, possibly aggravated by pulmonary infection. This shows that a rare disease such as endomyocardial fibrosis associated with massive calcification of the left ventricle may be suspected on a simple chest X-ray and confirmed by computed tomography.