Posterior cingulate cortex/precuneus blood oxygen-level dependent signal changes during the repetition of an attention task in meditators and nonmeditators.

BACKGROUND AND PURPOSE: Among several cognitive advantages, meditation is thought to enhance practitioners' capacity for sustained attention. In the present study, we explored this question by testing meditation practitioners (meditators) and nonpractitioners (nonmeditators) on a task that requires sustained attention, the Stroop Word-Color Task (SWCT), while using functional MRI. PARTICIPANTS AND METHODS: Participants were all right-handed and included 23 regular meditators as well as 17 nonmeditators. Participants viewed color words (i.e. 'red,' 'blue,' or 'green') presented one at a time on the screen that were written in either the same color (congruent condition) or a different color (incongruent condition) and were asked to indicate the color of the print. Participants also viewed noncolor words written in unrelated colors (neutral condition). Both groups completed the same two acquisition runs. RESULTS: Although both meditators and nonmeditators gave faster responses on run 2 than run 1 for both the neutral and incongruent trials, nonmeditators showed decreased activation and meditators showed increased activation in precuneus/posterior cingulate cortex. These regions were previously shown to be activated in the SWCT and belong to default mode network as well as to cognitive control network. CONCLUSION: Attention to repetitive stimuli during two equal runs of SWCT is mediated by the precuneus/posterior cingulate cortex, and mental training through meditation may influence the activity of these regions during such tasks.

Cognition and brain function in elderly Tai Chi practitioners: A case-control study.

OBJECTIVE: To compare cognition and brain function in elderly Tai Chi and Water Aerobics practitioners. METHODS: Eight Tai Chi (TC) and 8 Water Aerobics (WA) practitioners matched by gender, education and age underwent neuropsychological and fMRI scan during attention (Stroop Word Color Task) and working memory (N Back) tasks. RESULTS: Groups were similar for demographic and cognitive variables. Besides anxiety (smaller in TC group), there were no differences between groups in neuropsychological variables. During the Stroop Word Color Task, TC group had smaller brain activation in the right intracalcarine cortex, lateral occipital cortex, and occipital pole, than WA. During N back, TC group presented smaller brain activation in the right frontal pole and superior frontal gyrus. CONCLUSION: Despite the small number of participants in this preliminary study, both groups had similar cognitive performance, however the Tai Chi group required less brain activation to perform the attention and memory tasks, therefore they may have a more efficient cognitive performance than Water Aerobics group.

Effects of a 7-Day Meditation Retreat on the Brain Function of Meditators and Non-Meditators During an Attention Task.

Meditation as a cognitive enhancement technique is of growing interest in the field of health and research on brain function. The Stroop Word-Color Task (SWCT) has been adapted for neuroimaging studies as an interesting paradigm for the understanding of cognitive control mechanisms. Performance in the SWCT requires both attention and impulse control, which is trained in meditation practices. We presented SWCT inside the MRI equipment to measure the performance of meditators compared with non-meditators before and after a meditation retreat. The aim of this study was to evaluate the effects of a 7-day Zen intensive meditation training (a retreat) on meditators and non-meditators in this task on performance level and neural mechanisms. Nineteen meditators and 14 non-meditators were scanned before and after a 7-day Zen meditation retreat. No significant differences were found between meditators and non-meditators in the number of the correct responses and response time (RT) during SWCT before and after the retreat. Probably, due to meditators training in attention, their brain activity in the contrast incongruent > neutral during the SWCT in the anterior cingulate, ventromedial prefrontal cortex/anterior cingulate, caudate/putamen/pallidum/temporal lobe (center), insula/putamen/temporal lobe (right) and posterior cingulate before the retreat, were reduced compared with non-meditators. After the meditation retreat, non-meditators had reduced activation in these regions, becoming similar to meditators before the retreat. This result could be interpreted as an increase in the brain efficiency of non-meditators (less brain activation in attention-related regions and same behavioral response) promoted by their intensive training in meditation in only 7 days. On the other hand, meditators showed an increase in brain activation in these regions after the same training. Intensive meditation training (retreat) presented distinct effects on the attention-related regions in meditators and non-meditators probably due to differences in expertise, attention processing as well as neuroplasticity.

Machado-Joseph disease in Brazil: from the first descriptions to the emergence as the most common spinocerebellar ataxia.

Machado-Joseph disease is an autosomal dominant inherited disorder of Azorean ancestry firstly described in 1972. Since then, several Brazilian researchers have studied clinical and genetic issues related to the disease. Nowadays, Machado-Joseph disease is considered the most common spinocerebellar ataxia worldwide. Machado-Joseph disease still has no specific therapy to arrest progression, but the unclear pathophysiological mechanism, features related to genetic characteristics, phenotype variability, apparently global involvement of the nervous system in the disease and the therapeutic challenges continue to attract investigators in the field of spinocerebellar ataxias. Brazilian researchers have distinguished themselves in the ongoing investigation seeking new knowledge about Machado-Joseph disease.

Brain imaging analysis can identify participants under regular mental training.

Multivariate pattern recognition approaches have become a prominent tool in neuroimaging data analysis. These methods enable the classification of groups of participants (e.g. controls and patients) on the basis of subtly different patterns across the whole brain. This study demonstrates that these methods can be used, in combination with automated morphometric analysis of structural MRI, to determine with great accuracy whether a single subject has been engaged in regular mental training or not. The proposed approach allowed us to identify with 94.87% accuracy (p<0.001) if a given participant is a regular meditator (from a sample of 19 regular meditators and 20 non-meditators). Neuroimaging has been a relevant tool for diagnosing neurological and psychiatric impairments. This study may suggest a novel step forward: the emergence of a new field in brain imaging applications, in which participants could be identified based on their mental experience.

Pesquisas em cérebro e Práticas Contemplativas / Brain Research and Contemplative Practices

Introdução: Nos últimos anos tem havido um crescente interesse na investigação dos efeitos práticas de meditação na saúde mental e física. De alguma maneira, as habilidades treinadas durante as práticas meditativas, como o treinamento da atenção focada em um objeto específico, ou a monitoração dos padrões de pensamentos e emoções age modificando o funcionamento e a estrutura cerebrais. Recentemente, trabalhos na área de neuroimagem tem ajudado a elucidar possíveis mecanismo de ação das práticas meditativas no cérebro. Objetivo: revisar na literatura os estudos mais recentes sobre os efeitos da prática de meditação no cérebro e apresentar resultados de um protocolo com ressonância magnética funcional (fMRI) desenvolvido no Instituto do Cérebro do Hospital Israelita Albert Einstein (InCe-HIAE) sobre os efeitos da meditação na atenção. Método: revisão sobre estudos de neuroimagem funcional e estrutural e avaliação por fMRI de 39 sujeitos, 20 meditadores que realizam a prática há pelo menos 3 anos, por 3 vezes por semana e 20 sujeitos inexperientes em meditação. Resultados: estudos recentes têm mostrado alterações funcionais resultantes da prática de meditação, na atividade cerebral, bem como na estrutura do cérebro, como a espessura de áreas corticais. Nossos resultados preliminares corroboram com estes dados, mostrando que sujeitos que praticam meditação regularmente precisam recrutar menos áreas cerebrais, em especial frontais, do que pessoas inexperientes em meditação para ter o mesmo desempenho em uma tarefa atencional (o Stroop Word-Color Task). Conclusão: a prática de meditação pode trazer mudanças não apenas psicológicas, como mostram boa parte dos estudos, mas também modificações na fisiologia e anatomia cerebrais. Nosso estudo preliminar no InCe-HIAE indica que pessoas que praticam meditação regularmente podem apresentar um cérebro mais eficiente no desempenho de uma tarefa de atenção.

Meditation training increases brain efficiency in an attention task.

Meditation is a mental training, which involves attention and the ability to maintain focus on a particular object. In this study we have applied a specific attentional task to simply measure the performance of the participants with different levels of meditation experience, rather than evaluating meditation practice per se or task performance during meditation. Our objective was to evaluate the performance of regular meditators and non-meditators during an fMRI adapted Stroop Word-Colour Task (SWCT), which requires attention and impulse control, using a block design paradigm. We selected 20 right-handed regular meditators and 19 non-meditators matched for age, years of education and gender. Participants had to choose the colour (red, blue or green) of single words presented visually in three conditions: congruent, neutral and incongruent. Non-meditators showed greater activity than meditators in the right medial frontal, middle temporal, precentral and postcentral gyri and the lentiform nucleus during the incongruent conditions. No regions were more activated in meditators relative to non-meditators in the same comparison. Non-meditators showed an increased pattern of brain activation relative to regular meditators under the same behavioural performance level. This suggests that meditation training improves efficiency, possibly via improved sustained attention and impulse control.

Encefalopatia necrotizante aguda: paciente com evolução recidivante e letal / Acute necrotizing encephalopathy: patient with a relapsing and lethal evolution

A encefalopatia necrotizante aguda foi descrita inicialmente em crianças japonesas e se caracteriza por rápida evolução e lesões simétricas no tronco encefálico, cerebelo e especialmente nos tálamos. Avaliamos uma menina de 7 meses de idade, que apresentou dois episódios de depressão da consciência de rápida instalação e paresias, sem alterações metabólicas. Houve uma rápida melhora na primeira crise, porém o segundo episódio foi fulminante, tendo evoluído para estado de morte encefálica em dois dias. Os estudos de ressonância magnética mostraram lesões simétricas nos tálamos e acometimento também do tronco encefálico e cerebelo.

Acute necrotizing encephalopathy was initially reported in Japanese children. The rapid evolution and symmetrical brain lesions seen in the brainstem, cerebellum and specially in the thalamus characterize the disease. We studied a 7-month-old-girl, who presented with two episodes of rapid loss of consciousness and paresis without metabolic disturbances. At the first time she had a rapid improvement, but at the second episode the course was fulminant and in two days she lapsed into a clinical state of brain death. The magnetic resonance studies showed symmetrical lesions in the thalamus and additional lesions involving the brainstem and the cerebellum.

Frequency of the different mutations causing spinocerebellar ataxia (SCA1, SCA2, MJD/SCA3 and DRPLA) in a large group of Brazilian patients

Spinocerebellar ataxia type 1 (SCA1), spinocerebellar ataxia type 2 (SCA2) and Machado-Joseph disease or spinocerebellar ataxia type 3 (MJD/SCA3) are three distinctive forms of autosomal dominant spinocerebellar ataxia (SCA) caused by expansions of an unstable CAG repeat localized in the coding region of the causative genes. Another related disease, dentatorubropallidoluysian atrophy (DRPLA) is also caused by an unstable triplet repeat and can present as SCA in late onset patients. We investigated the frequency of the SCA1, SCA2, MJD/SCA3 and DRPLA mutations in 328 Brazilian patients with SCA, belonging to 90 unrelated families with various patterns of inheritance and originating in different geographic regions of Brazil. We found mutations in 35 families (39 percent), 32 of them with a clear autosomal dominant inheritance. The frequency of the SCA1 mutation was 3 percent of all patients; and 6 percent in the dominantly inherited SCAs. We identified the SCA2 mutation in 6 percent of all families and in 9 percent of the families with autosomal dominant inheritance. The MJD/SCA3 mutation was detected in 30 percent of all patients; and in the 44 percent of the dominantly inherited cases. We found no DRPLA mutation. In addition, we observed variability in the frequency of the different mutations according to geographic origin of the patients, which is probably related to the distinct colonization of different parts of Brazil. These results suggest that SCA may be occasionally caused by the SCA1 and SCA2 mutations in the Brazilian population, and that the MJD/SCA3 mutation is the most common cause of dominantly inherited SCA in Brazil.

Machado-Joseph disease of Azorean ancestry in Brazil: the Catarina kindred; neurological, neuroimaging, psychiatric and neuropsychological findings in the largest known family, the Catarina kindred

Há, até o momento, notícia de 9 famílias näo aparentadas com o diagnóstico clínico de doença de Machado-Joseph (MJD) no Brasil. Esta é a maior família do mundo com doença. É de origem açoriana e contem 622 indivíduos na árvore fenealógica. Destes, 236 foram examinados. Dois examinadores julgaron 39 como afetados. Respectivamente 12, 23 e 4 pacientes tinham os fenôtipos I, II e III da doença, com idades no início variando entre 10-48, 14-54 e 30-55. Doença tipo I de início juvenil näo mostrou atrofia täo severa nas imagens por ressonância magnética (RM) quanto doença tipo II de duraçäo igual, demonstrando que severidade clínica e grau de atrofia näo caminham paralelamente. Nenhum dos 8 pacientes examinados por RM tinha atrofia olivar ou anormalidades no globo pálido. Doze pacientes e 23 sob risco foram submetidos a avaliaçäo neuropsicológica. A atençäo foi normal em todos. Memória verbal estava pior nos doentes com maior decaimento com o tempo que nos sob risco. Ambos os grupos tiveram pontuaçäo abaixo do normal na identificaçäo de silhuetas e praxia construtiva. Memória visual estava bem abaixo do normal para ambos, com muitas rotaçöes, porém sem omissöes ou confabulaçäo. Padräo peculiar de multiplicaçäo dos detalhes internos, que denominamos o "efeito olho de mosca" foi visto em 6 doentes e 8 sob risco. Discriminaçäo defeituosa de cores, quando múltiplas cores eram apresentadas lado a lado, na ausência de anomia ou cegueira a cores, caracterizável como "simultagnosia a cores", surgiu como achado e foi pesquisada em 29 sujeitos 4/10 doentes e 6/19 sob risco mostram esta dificuldade. Conclui-se que disfunçöes cognitivas na esfera visual säo proeminentes nesta família. Se seriam próprias da doença e manifestaçäo precoce daqueles sob risco, está ainda para ser estabelecido. Depressäo foi avaliada com critérios do DSM III-R e com o Montgomery-Asberg Depression Rating Scale. Näo houve diferença entre doentes e sob risco. Entretanto, os pacientes tiveram menos depressäo do que tinham tido antes ou nas fases precoces da doença. A MJD plenamente instalada parecia exercer efeito protetor da depressäo