RESUMO
Extrastriate visual area V5/MT in primates is defined both structurally by myeloarchitecture and functionally by distinct responses to visual motion. Myelination is directly identifiable from postmortem histology but also indirectly by image contrast with structural magnetic resonance imaging (sMRI). First, we compared the identification of V5/MT using both sMRI and histology in Rhesus macaques. A section-by-section comparison of histological slices with in vivo and postmortem sMRI for the same block of cortical tissue showed precise correspondence in localizing heavy myelination for V5/MT and neighboring MST. Thus, sMRI in macaques accurately locates histologically defined myelin within areas known to be motion selective. Second, we investigated the functionally homologous human motion complex (hMT+) using high-resolution in vivo imaging. Humans showed considerable intersubject variability in hMT+ location, when defined with myelin-weighted sMRI signals to reveal structure. When comparing sMRI markers to functional MRI in response to moving stimuli, a region of high myelin signal was generally located within the hMT+ complex. However, there were considerable differences in the alignment of structural and functional markers between individuals. Our results suggest that variation in area identification for hMT+ based on structural and functional markers reflects individual differences in human regional brain architecture.
Assuntos
Variação Biológica Individual , Córtex Visual/diagnóstico por imagem , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Animais , Mapeamento Encefálico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Macaca mulatta , Imageamento por Ressonância Magnética , Masculino , Bainha de Mielina , Especificidade da Espécie , Córtex Visual/anatomia & histologia , Vias Visuais/anatomia & histologia , Vias Visuais/diagnóstico por imagem , Vias Visuais/fisiologia , Adulto JovemRESUMO
Vitamin D and its metabolites have pleomorphic roles in both nervous system health and disease. Animal models have been paramount in contributing to our knowledge and understanding of the consequences of vitamin D deficiency on brain development and its implications for adult psychiatric and neurological diseases. The conflation of in vitro, ex vivo, and animal model data provide compelling evidence that vitamin D has a crucial role in proliferation, differentiation, neurotrophism, neuroprotection, neurotransmission, and neuroplasticity. Vitamin D exerts its biological function not only by influencing cellular processes directly, but also by influencing gene expression through vitamin D response elements. This review highlights the epidemiological, neuropathological, experimental and molecular genetic evidence implicating vitamin D as a candidate in influencing susceptibility to a number of psychiatric and neurological diseases. The strength of evidence varies for schizophrenia, autism, Parkinson's disease, amyotrophic lateral sclerosis, Alzheimer's disease, and is especially strong for multiple sclerosis.
Assuntos
Doenças do Sistema Nervoso/metabolismo , Sistema Nervoso/metabolismo , Vitamina D/metabolismo , Humanos , Sistema Nervoso/fisiopatologia , Doenças do Sistema Nervoso/fisiopatologia , Deficiência de Vitamina D/metabolismo , Deficiência de Vitamina D/fisiopatologiaRESUMO
Recurrence of duodenal ulcer was diagnosed in 15 patients who underwent highly selective vagotomy before 6-13 years, i.e. in 12.2%. Factors possibly contributing to such a recurrence were analysed. Patients with ulcer recurrence were: 1) non-qualified workers, 2) tobacco smokers, 3) heavy drinkers, 4) users of ulcerogenic medicines, and 5) were involved into conflict situations.