Navegando por Autor "Araújo, Dráulio Barros de"

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Acute effects of ayahuasca in a juvenile non-human primate model of depression
(2018-11-08) Silva, Flávia S. da; Silva, Erick A. S.; Sousa Jr., Geovan M. de; Maia-de-Oliveira, João P.; Soares-Rachetti, Vanessa de Paula; Araújo, Dráulio Barros de; Sousa, Maria Bernardete Cordeiro de; Lobão-Soares, Bruno; Hallak, Jaime; Galvão-Coelho, Nicole L.
Objective: The incidence rate of major depression in adolescents reaches approximately 14%. This disorder is usually recurrent, without remission of symptoms even after pharmacological treatment, and persists throughout adult life. Since the effects of antidepressants take approximately 2 weeks to begin, new pharmacological therapies are under continuous exploration. Recent evidence suggests that psychedelics could produce rapid antidepressant effects. In this study, we evaluated the potential antidepressant effects of ayahuasca in a juvenile non-human primate model of depression. Methods: While living with their families, juvenile marmosets (8 males; 7 females) were observed on alternate days for four weeks during a baseline phase. This was followed by 8 weeks of an induced depressive state protocol, the social isolated context (IC), in which the animals were monitored in the first and last weeks. Subsequently, five males and four females were randomly selected for treatment, first with a single administration of saline vehicle (1.67 mL/300 g of body weight, via gavage), followed by a single dose of ayahuasca (1.67 mL/300 g of body weight, via gavage). Both phases lasted 1 week and the animals were monitored daily. A third week of sampling was called the tardive-pharmacological effects phase. In all phases the marmosets were assessed for behavior, fecal cortisol levels, and body weight. Results: After IC, the animals presented typical hypocortisolemia, but cortisol recovered to baseline levels 24 h after an acute dose of ayahuasca; this recovery was not observed in vehicle-treated animals. Additionally, in males, ayahuasca, but not the vehicle, reduced scratching, a stereotypic behavior, and increased feeding. Ayahuasca treatment also improved body weight to baseline levels in both sexes. The ayahuasca-induced behavioral response had long-term effects (14 days). Thus, in this translational juvenile animal model of depression, ayahuasca presented beneficial effects. Conclusions: These results can contribute to the validation of ayahuasca as an antidepressant drug and encourage new studies on psychedelic drugs as a tool for treating mood disorders, including for adolescents with early-onset depression.
Alterações da default mode network provocadas pela ingestão de Ayahuasca investigadas por Ressonância Magnética Funcional
(Universidade Federal do Rio Grande do Norte, 2012-05-25) Fontes, Fernanda Palhano Xavier de; Araújo, Dráulio Barros de; ; http://lattes.cnpq.br/7818012155694188; ; http://lattes.cnpq.br/5303845192389002; Ribeiro, Sidarta Tollendal Gomes; ; http://lattes.cnpq.br/0649912135067700; Amaro Júnior, Edson; ; http://lattes.cnpq.br/5927371795409877
A Ayahusca é uma bebida psicotrópica que tem sido utilizada há séculos por populações originais da América do Sul, notadamente da região Amazônica, com fins religiosos e medicinais. O chá é obtido pela decocção de folhas da Psychotria viridis com a casca e tronco de um arbusto, a Banisteriopsis caapi. A primeira é rica em N,N-dimetiltriptamina (DMT), que tem importante e bem conhecido efeito alucinógeno devido a sua atuação agonista nos receptores de serotonina, especificamente 5-HT2A. Por outro lado, as β-carbolinas presentes na B. caapi, particularmente a harmina e a harmalina, são potentes inibidores da monoamina oxidase (iMAO). Além disso, a tetrahidroharmina (THH), também presente na B. caapi, atua como leve inibidor seletivo da recaptação de serotonina e um fraco inibidor de MAO. Essa composição única provoca uma série de alterações afetivas, sensoriais, perceptuais e cognitivas em indivíduos sob o efeito da Ayahuasca. Por outro lado, existe um interesse crescente na rede de modo padrão, do inglês Default Mode Network (DMN), que tem sido consistentemente observada em estudos de neuroimagem funcional. As principais componentes dessa rede incluem estruturas da linha média do córtex cerebral, como o córtex frontomedial anterior, córtex frontomedial ventral, o giro cingulado posterior, o pré-cuneus e algumas regiões do lobo parietal inferior e do giro temporal médio. Acredita-se que a DMN participe de tarefas que envolvem autojulgamentos, evocação de memórias autobiográficas, realização de simulações mentais, pensar em perspectiva, estados meditativos, entre outros. De maneira geral, essas tarefas requerem um foco de atenção interno, daí a conclusão de que a DMN estaria associada à atividade mental introspectiva. Assim, este estudo teve como objetivo avaliar, por meio de ressonância magnética funcional (fMRI), as possíveis mudanças da DMN causadas pela ingestão da Ayahuasca em 10 voluntários saudáveis investigados enquanto se submeteram a dois protocolos: uma tarefa de fluência verbal e a aquisição de dados contínuos durante estado de repouso. De maneira geral, observa-se que a Ayahuasca provoca redução na amplitude do sinal de fMRI nos nodos centrais da DMN, tais como o cíngulo anterior, o córtex pré-frontal medial, o cíngulo posterior, o pré-cuneus e o lobo parietal inferior. Além disso, também foram observadas alterações no padrão de conectividade da DMN, em particular, diminuição da conectividade funcional no pré-cuneus. Juntos, esses achados indicam a possível associação entre o estado alterado de consciência experimentado pelos indivíduos sob efeito da Ayahuasca, e mudanças no fluxo de pensamentos espontâneos ligados ao aumento da introspecção
Amygdala responses to unpleasant pictures are influenced by task demands and positive affect trait
(2015-03-04) Sanchez, Tiago A.; Mocaiber, Izabela; Erthal, Fatima S.; Joffily, Mateus; Volchan, Eliane; Pereira, Mirtes G.; Araújo, Dráulio Barros de; Oliveira, Leticia
The role of attention in emotional processing is still the subject of debate. Recent studies have found that high positive affect in approach motivation narrows attention. Furthermore, the positive affect trait has been suggested as an important component for determining human variability in threat reactivity. We employed functional magnetic resonance imaging to investigate whether different states of attention control would modulate amygdala responses to highly unpleasant pictures relative to neutral and whether this modulation would be influenced by the positive affect trait. Participants (n = 22, 12 male) were scanned while viewing neutral (people) or unpleasant pictures (mutilated bodies) flanked by two peripheral bars. They were instructed to (a) judge the picture content as unpleasant or neutral or (b) to judge the difference in orientation between the bars in an easy condition (0 or 90∘ orientation difference) or (c) in a hard condition (0 or 6∘ orientation difference). Whole brain analysis revealed a task main effect of brain areas related to the experimental manipulation of attentional control, including the amygdala, dorsolateral prefrontal cortex, and posterior parietal cortex. Region of interest analysis showed an inverse correlation (r = -0.51, p < 0.01) between left amygdala activation and positive affect level when participants viewed unpleasant stimuli and judged bar orientation in the easy condition. This result suggests that subjects with high positive affect exhibit lower amygdala reactivity to distracting unpleasant pictures. In conclusion, the current study suggests that positive affect modulates attention effect on unpleasant pictures, therefore attenuating emotional responses.
Análises da mediação e moderação do mindfulness sobre medidas de afeto, ansiedade e estresse em adultos jovens saudáveis
(2020-01-16) Sousa Júnior, Geovan Menezes de; Sousa, Maria Bernardete Cordeiro de; ; ; Araújo, Dráulio Barros de; ; Lopez, Luiz Carlos Serramo;
O estilo de vida contemporâneo tem promovido forte impacto na saúde e bem-estar mental das pessoas, conforme sugerem indicadores atuais da Organização Mundial de Saúde. Tal comprometimento, geralmente, está vinculado à desregulação dos mecanismos psicofisiológicos da resposta ao estresse, dada à variedade e à frequência de eventos estressores aos quais a população está exposta diariamente. Neste contexto, intervenções não-medicamentosas para reduzir o impacto destes agentes têm sido utilizadas, entre as quais, aquelas que integram as dimensões mente x corpo, como o mindfulness (ou atenção plena). Esta prática meditativa, que tem sido implicada na redução de sintomas de ansiedade, depressão e estresse, é normalmente definida em termos da habilidade para voltar a atenção ao momento presente com abertura, aceitação e gentileza, sendo avaliada como um estado ou um traço. Deste modo, o presente estudo se propôs a demonstrar, por meio de uma abordagem exploratória, se uma prática breve de mindfulness é influenciada pelo traço ou estado de mindfulness, ou ambos, e interfere sobre variáveis que expressam bem-estar psicológico. As nossas hipóteses predizem que (1) o alto traço de mindfulness está associado a melhor bem-estar psicológico; (2) a prática breve de mindfulness reduz os indicadores negativos e aumenta os indicadores positivos de bem-estar psicológico e, (3) essas mudanças são mediadas pelo aumento no estado de mindfulness induzido pela prática. A amostra foi formada por jovens universitários saudáveis (n=40; 20 homens) e foram coletadas medidas associadas à ansiedade (IDATE), afeto (PANAS), estresse (PSS, cortisol plasmático) e mindfulness (estado, SMS; traço, FFMQ). Inicialmente, por meio de uma análise de cluster (k-means), tais indivíduos foram classificados como alto/baixo traço de mindfulness, na qual aqueles com traço alto apresentaram menores níveis de estado e traço de ansiedade e de estresse percebido. Adicionalmente, a amostra foi testada a partir de sua divisão em um grupo controle (GC, n=20) e um grupo mindfulness (GM, n=20) utilizando uma análise de variância mista (between: grupo, within: sessão [antes/após intervenção]) para investigar o efeito da intervenção entre e dentre os grupos. Apenas dentro do GM houve redução do estado de ansiedade e do estresse percebido, e aumento do estado de mindfulness, após a prática. Dentro de ambos os grupos houve redução do afeto negativo e dos níveis plasmáticos de cortisol, e nenhuma diferença foi encontrada em relação ao afeto positivo. Uma análise de mediação moderada evidenciou que o aumento do estado de mindfulness medeia aumento no afeto positivo e redução no estresse percebido e no cortisol. O efeito de mediação do estado de mindfulness na diminuição da ansiedade estado só ocorreu em indivíduos com alto traço de mindfulness. A despeito das limitações do tamanho amostral e da natureza exploratória do estudo, que utilizou múltiplas testagens para o mesmo conjunto de dados, esses resultados sugerem que o traço de mindfulness está associado a baixos níveis de estresse, e que uma intervenção breve baseada em mindfulness promove uma atenuação na resposta psicofisiológica negativa e media aumento no afeto positivo. Estes resultados apontam para um efeito positivo de uma prática breve de mindfulness, em um grupo específico de indivíduos, e abre perspectivas para novas investigações e sua aplicação em diferentes populações.
Anatomical and functional MRI changes after one year of auditory rehabilitation with hearing aids
(2018-09-10) Pereira-Jorge, M. R.; Andrade, K. C.; Palhano-Fontes, F. X.; Diniz, P. R. B.; Sturzbecher, M.; Santos, A. C.; Araújo, Dráulio Barros de
Hearing aids (HAs) are an effective strategy for auditory rehabilitation in patients with peripheral hearing deficits. Yet, the neurophysiological mechanisms behind HA use are still unclear. Thus far, most studies have focused on changes in the auditory system, although it is expected that hearing deficits affect a number of cognitive systems, notably speech. In the present study, we used audiometric evaluations in 14 patients with bilateral hearing loss before and after one year of continuous HA use and functional magnetic resonance imaging (fMRI) and cortical thickness analysis in 12 and 10 of them compared with a normal hearing control group. Prior to HA fitting, fMRI activity was found reduced in the auditory and language systems and increased in visual and frontal areas, expanding to multimodal integration cortices, such as the superior temporal gyrus, intraparietal sulcus, and insula. One year after rehabilitation with HA, significant audiometric improvement was observed, especially in free-field Speech Reception Threshold (SRT) test and functional gain, a measure of HA efficiency. HA use increased fMRI activity in the auditory and language cortices and multimodal integration areas. Individual fMRI signal changes from all these areas were positively correlated with individual SRT changes. Before rehabilitation, cortical thickness was increased in parts of the prefrontal cortex, precuneus, fusiform gyrus, and middle temporal gyrus. It was reduced in the insula, supramarginal gyrus, medial temporal gyrus, occipital cortex, posterior cingulate cortex, and claustrum. After HA use, increased cortical thickness was observed in multimodal integration regions, particularly the very caudal end of the superior temporal sulcus, the angular gyrus, and the inferior parietal gyrus/superior temporal gyrus/insula. Our data provide the first evidence that one year of HA use is related to functional and anatomical brain changes, notably in auditory and language systems, extending to multimodal cortices.
Antecedent descriptions change brain reactivity to emotional stimuli: a Functional Magnetic Resonance imaging study of an extrinsic and incidental reappraisal strategy
(2011) MOCAIBER, I.; SANCHEZ, T. A.; PEREIRA, M. G.; ERTHAL, F. S.; JOFFILY, M.; Araújo, Dráulio Barros de; VOLCHAN, E.; OLIVEIRA, L. DE
In the present study we investigated whether individuals would take advantage of an extrinsic and incidental reappraisal strategy by giving them precedent descriptions to attenuate the emotional impact of unpleasant pictures. In fact, precedent descriptions have successfully promoted down-regulation of electrocortical activity and physiological responses to unpleasant pictures. However, the neuronal substrate underlying this effect remains unclear. Particularly, we investigated whether amygdala and insula responses, brain regions consistently implicated in emotional processing, would be modulated by this strategy. To achieve this, highly unpleasant pictures were shown in two contexts in which a prior description presented them as taken from movie scenes (fictitious) or real scenes. Results showed that the fictitious condition was characterized by down-regulation of amygdala and insula responses. Thus, the present study provides new evidence on reappraisal strategies to downregulate emotional reactions and suggest that amygdala and insula responses to emotional stimuli are adaptive and highly flexible.
Antidepressant effects of a single dose of ayahuasca in patients with recurrent depression: a preliminary report
(2015) Osório, Flávia de L.; Sanches, Rafael F.; Macedo, Ligia R.; Santos, Rafael G. dos; Maia-de-Oliveira, João P.; Wichert-Ana, Lauro; Araújo, Dráulio Barros de; Riba, Jordi; Crippa, José A.; Hallak, Jaime E.
Objectives: Ayahuasca (AYA), a natural psychedelic brew prepared from Amazonian plants and rich in dimethyltryptamine (DMT) and harmine, causes effects of subjective well-being and may therefore have antidepressant actions. This study sought to evaluate the effects of a single dose of AYA in six volunteers with a current depressive episode. Methods: Open-label trial conducted in an inpatient psychiatric unit. Results: Statistically significant reductions of up to 82% in depressive scores were observed between baseline and 1, 7, and 21 days after AYA administration, as measured on the Hamilton Rating Scale for Depression (HAM-D), the Montgomery-Åsberg Depression Rating Scale (MADRS), and the Anxious-Depression subscale of the Brief Psychiatric Rating Scale (BPRS). AYA administration resulted in nonsignificant changes in Young Mania Rating Scale (YMRS) scores and in the thinking disorder subscale of the BPRS, suggesting that AYA does not induce episodes of mania and/or hypomania in patients with mood disorders and that modifications in thought content, which could indicate psychedelic effects, are not essential for mood improvement. Conclusions: These results suggest that AYA has fast-acting anxiolytic and antidepressant effects in patients with a depressive disorder.
Antidepressant Effects of a Single Dose of Ayahuasca in Patients With Recurrent Depression: A SPECT Study
(2016) Sanches, Rafael Faria; Osório, Flávia de Lima; Santos, Rafael G. dos; Macedo, Ligia R.H.; Maia-de-Oliveira, João Paulo; Wichert-Ana, Lauro; Araújo, Dráulio Barros de; Riba, Jordi; Crippa, José Alexandre S.; Hallak, Jaime E.C.
Ayahuasca is an Amazonian botanical hallucinogenic brew which contains dimethyltryptamine, a 5-HT2A receptor agonist, and harmine, a monoamine-oxidase A inhibitor. Our group recently reported that ayahuasca administration was associated with fast-acting antidepressive effects in 6 depressive patients. The objective of the present work was to assess the antidepressive potentials of ayahuasca in a bigger sample and to investigate its effects on regional cerebral blood flow. In an open-label trial conducted in an inpatient psychiatric unit, 17 patients with recurrent depression received an oral dose of ayahuasca (2.2 mL/kg) and were evaluated with the Hamilton Rating Scale for Depression, the Montgomery-Åsberg Depression Rating Scale, the Brief Psychiatric Rating Scale, the Young Mania Rating Scale, and the Clinician Administered Dissociative States Scale during acute ayahuasca effects and 1, 7, 14, and 21 days after drug intake. Blood perfusion was assessed eight hours after drug administration by means of single photon emission tomography. Ayahuasca administration was associated with increased psychoactivity (Clinician Administered Dissociative States Scale) and significant score decreases in depression-related scales (Hamilton Rating Scale for Depression, Montgomery-Åsberg Depression Rating Scale, Brief Psychiatric Rating Scale) from 80 minutes to day 21. Increased blood perfusion in the left nucleus accumbens, right insula and left subgenual area, brain regions implicated in the regulation of mood and emotions, were observed after ayahuasca intake. Ayahuasca was well tolerated. Vomiting was the only adverse effect recorded, being reported by 47% of the volunteers. Our results suggest that ayahuasca may have fast-acting and sustained antidepressive properties. These results should be replicated in randomized, double-blind, placebo-controlled trials.
Application of Partial Directed Coherence to the Analysis of Resting-State EEG-fMRI Data
(2013) Biazoli Jr., Claudinei E.; Sturzbecher, Marcio; White, Thomas P.; Onias, Heloisa Helena dos Santos; Andrade, Katia Cristine; Araújo, Dráulio Barros de; Sato, João R.
The simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data potentially allows measurement of brain signals with both high spatial and temporal resolution. Partial directed coherence (PDC) is a Granger causality measure in the frequency domain, which is often used to infer the intensity of information flow over the brain from EEG data. In the current study, we propose a new approach to investigate functional connectivity in resting-state (RS) EEG-fMRI data by combining time-varying PDC with the analysis of blood oxygenation level-dependent (BOLD) signal fluctuations. Basically, we aim to identify brain circuits that are more active when the information flow is increased between distinct remote neuronal modules. The usefulness of the proposed method is illustrated by application to simultaneously recorded EEG-fMRI data from healthy subjects at rest. Using this approach, we decomposed the nodes of RS networks in fMRI data according to the frequency band and directed flow of information provided from EEG. This approach therefore has the potential to inform our understanding of the regional characteristics of oscillatory processes in the human brain.
Arterial Spin Labeling Measurements of Cerebral Perfusion Territories in Experimental Ischemic Stroke
(2011) Leoni, Renata F.; Paiva, Fernando F.; Kang, Byeong-Teck; Henning, Erica C.; Nascimento, George Carlos; Tannús, Alberto; Araújo, Dráulio Barros de; Silva, Afonso C.
Collateral circulation, defined as the supplementary vascular network that maintains cerebral blood flow (CBF) when the main vessels fail, constitutes one important defense mechanism of the brain against ischemic stroke. In the present study, continuous arterial spin labeling (CASL) was used to quantify CBF and obtain perfusion territory maps of the major cerebral arteries in spontaneously hypertensive rats (SHRs) and their normotensive Wistar-Kyoto (WKY) controls. Results show that both WKY and SHR have complementary, yet significantly asymmetric perfusion territories. Right or left dominances were observed in territories of the anterior (ACA), middle and posterior cerebral arteries, and the thalamic artery. Magnetic resonance angiography showed that some of the asymmetries were correlated with variations of the ACA. The leptomeningeal circulation perfusing the outer layers of the cortex was observed as well. Significant and permanent changes in perfusion territories were obtained after temporary occlusion of the right middle cerebral artery in both SHR and WKY, regardless of their particular dominance. However, animals with right dominance presented a larger volume change of the left perfusion territory (23±9%) than animals with left dominance (7±5%, P<0.002). The data suggest that animals with contralesional dominance primarily safeguard local CBF values with small changes in contralesional perfusion territory, while animals with ipsilesional dominance show a reversal of dominance and a substantial increase in contralesional perfusion territory. These findings show the usefulness of CASL to probe the collateral circulation.
ArticleNeuroimaging in stroke and non-stroke pusher patients
(2011-07-11) Santos-Pontelli, Taiza Elaine Grespan; Pontes-Neto, Octavio Marques; Araújo, Dráulio Barros de; Santos, Antonio Carlos dos; Leite, João Pereira
Pusher behavior (PB) is a disorder of postural control affecting patients with encephalic lesions. This study has aimed to identify the brain substrates that are critical for the occurrence of PB, to analyze the influence of the midline shift (MS) and hemorrhagic stroke volume (HSV) on the severity and prognosis of the PB. We identified 31 pusher patients of a neurological unit, mean age 67.4±11.89, 61.3% male. Additional neurological and functional examinations were assessed. Neuroimaging workup included measurement of the MS, the HSV in patients with hemorrhagic stroke, the analysis of the vascular territory, etiology and side of the lesion. Lesions in the parietal region (p=0.041) and thalamus (p=0.001) were significantly more frequent in PB patients. Neither the MS nor the HSV were correlated with the PB severity or recovery time. Key words: pusher behavior, stroke, postural control.
Aspectos epidemiológicos, cognitivo-comportamentais e neurofisiológicos do sonho lúcido
(Universidade Federal do Rio Grande do Norte, 2012-06-19) Rolim, Sergio Arthuro Mota; Ribeiro, Sidarta Tollendal Gomes; ; http://lattes.cnpq.br/0649912135067700; ; http://lattes.cnpq.br/4726737296252279; Queiroz, Cláudio Marcos Teixeira de; ; http://lattes.cnpq.br/3384801391828521; Araújo, Dráulio Barros de; ; http://lattes.cnpq.br/7818012155694188; Louzada, Fernando Mazziolli; ; LOUZADA, F. M.; Pinto Júnior, Luciano Ribeiro; ; http://lattes.cnpq.br/2043213918636905
O sonho lúcido (SL) é um estado mental no qual o sujeito está consciente de estar sonhando durante o sonho. A prevalência do SL em Europeus, Norte-Americanos e Asiáticos é bastante variável (entre 26 e 92%) (Stepansky et al., 1998; Erlacher & Schredl, 2011; Yu, 2008) e em Latino-Americanos ainda não foi investigada. Além disso, as bases neurais do SL permanecem controversas. Diferentes estudos observaram um aumento da potência na frequência alfa (Tyson et al., 1984), na oscilação beta na área parietal (Holzinger et al., 2006) e no ritmo gama na região frontal (Voss et al., 2009) durante o SL em relação ao não lúcido. Assim, para investigar a questão epidemiológica (Estudo 1), elaboramos um questionário online sobre sonhos que foi respondido por 3427 voluntários. Em nossa amostra, 56% são mulheres, 24% são homens e 20% não responderam o gênero; a mediana de idade foi de 25 anos. Um total de 76,5% dos indivíduos refere que lembra dos sonhos pelo menos uma vez por semana. Cerca de dois terços dos sujeitos observam o sonho em primeira pessoa, ou seja, vendo o sonho da própria perspectiva e não como mais um dos personagens do sonho. Os elementos mais comuns nos sonhos são movimentos/ações (93,3%), pessoas conhecidas (92,9%), sons/vozes (78,5%) e imagens coloridas (76,3%). O conteúdo onírico se relaciona principalmente com planos para o dia seguinte (37,8%) e memórias do dia anterior (13,8%). Os pesadelos apresentam principalmente ansiedade/medo (65,5%), ser perseguido (48,5%) e sensações desagradáveis que não envolvem dor (47,6%). Assim, sonhos e pesadelos podem ser evolutivamente entendidos como uma simulação das situações frequentes que acontecem na vida e que se relacionam com a nossa integridade social, psicológica e biológica. Observamos também que a maioria dos indivíduos (77,2%) relata ter tido pelo menos um SL, tendo experimentado na sua maior parte até 10 episódios (44,9%). A frequência do SL foi fracamente correlacionada com a frequência de lembrança dos sonhos (r=0,20, p<0,001) e foi também maior em homens (χ2=10,2, p= 0,001). O controle do SL é raro (29,7%) e inversamente correlacionado com o tempo de duração do SL (r=- 0,38, p<0,001), que normalmente é curto: para 48,5% dos sujeitos o SL dura menos que 1 minuto. A ocorrência do SL é principalmente facilitada pela possibilidade de dormir sem hora para acordar (38,3%) que aumenta a chance de ter sono REM (SREM), e estresse (30,1%) que aumenta também as transições do SREM para a vigília. Como conclusão, nossos resultados indicam que o SL é uma experiência relativamente comum (mas não recorrente), geralmente fugaz e difícil de controlar, o que sugere que o SL é um estágio intermediário, incompleto e estacionário (ou fase de transição) entre o SREM e a vigília. Além disso, apesar das populações Europeias, Norte-Americanas e Asiáticas terem uma prevalência de SL bastante variável, nossos dados de uma amostra de Latino-Americanos fortalecem a noção de que o SL é um fenômeno universal da espécie humana. Para investigar as bases neurais do SL (Estudo 2), realizamos registros de sono em 32 sujeitos que não apresentam SL de forma frequente, e investigamos 6 sujeitos que apresentam SL recorrentemente. A primeira amostra foi submetida a duas técnicas cognitivo-comportamentais para induzir o SL: sugestão pré- sono (n = 8) e incubação de estímulos do ambiente (pulsos de luz) no sonho durante o SREM (n = 8). Um grupo controle não foi submetido a nenhuma das duas técnicas (n = 16). Os resultados indicam que é muito difícil induzir SL em laboratório, uma vez que conseguimos obter apenas um SL em um sujeito, que era do grupo em que aplicamos a técnica de sugestão pré-sono. O sinal eletroencefalográfico deste voluntário apresentou pulsos de ritmo alfa (7-14Hz) anteriores ao SL, de forma breve (aproximadamente 3s), sem alteração significativa do tônus muscular e independente da presença de movimentos oculares rápidos. O SL desse sujeito apresentou também uma maior potência do ritmo alfa (7-14Hz) na região occipital e um aumento de atividade gama (20- 50Hz) na região temporo-parietal direita. Nos 6 sujeitos que frequentemente têm SL, o mesmo apresentou em média um aumento de potência em gama alto (50-100Hz) na região frontal em comparação com o SREM não-lúcido; no entanto, isso aconteceu de forma clara para apenas um dos indivíduos. Observamos também que quatro desses voluntários apresentaram um aumento da potência do ritmo alfa na região occipital, pouco antes do SL, ou durante o mesmo. Dessa forma, nossos resultados preliminares sugerem que o SL apresenta diferentes características neurofisiológicas dos estados típicos de SREM e vigília: 1) Os pulsos de ritmo alfa, bem como o aumento da potência dessa oscilação na região occipital, podem ser micro-despertares. Estes facilitam o contato do cérebro durante o sono com o meio externo, favorecendo a ocorrência do SL e fortalecendo a ideia de que o SL seria um estado intermediário entre o sono e a vigília. 2) Como as regiões temporoparietal direita e frontal se relacionam com a formação da auto-consciência e da imagem corporal, sugerimos que um aumento de atividade nessas regiões durante o sono pode ser o mecanismo neurobiológico subjacente ao SL
Assessing Cerebrovascular Reactivity in Carotid Steno-Occlusive Disease UsingMRI BOLD and ASL Techniques
(2012-04-17) Leoni, Renata F.; Mazzetto-Betti, Kelley C.; Silva, Afonso C.; Santos, Antonio C. dos; Araújo, Dráulio Barros de; Leite, João P.; Pontes-Neto, Octavio M.
Impaired cerebrovascular reactivity (CVR), a predictive factor of imminent stroke, has been shown to be associated with carotid steno-occlusive disease. Magnetic resonance imaging (MRI) techniques, such as blood oxygenation level-dependent (BOLD) and arterial spin labeling (ASL), have emerged as promising noninvasive tools to evaluate altered CVR with whole-brain coverage, when combined with a vasoactive stimulus, such as respiratory task or injection of acetazolamide. Under normal cerebrovascular conditions, CVR has been shown to be globally and homogenously distributed between hemispheres, but with differences among cerebral regions. Such differences can be explained by anatomical specificities and different biochemical mechanisms responsible for vascular regulation. In patients with carotid steno-occlusive disease, studies have shown that MRI techniques can detect impaired CVR in brain tissue supplied by the affected artery. Moreover, resulting CVR estimations have been well correlated to those obtained with more established techniques, indicating that BOLD and ASL are robust and reliable methods to assess CVR in patients with cerebrovascular diseases. Therefore, the present paper aims to review recent studies which use BOLD and ASL to evaluate CVR, in healthy individuals and in patients with carotid steno-occlusive disease, providing a source of information regarding the obtained results and the methodological difficulties.
Assessing the psychedelic "after-glow" in ayahuasca users: post-acute neurometabolic and functional connectivity changes are associated with enhanced mindfulness capacities
(2017-06-13) Sampedro, Frederic; de la Fuente Revenga, Mario; Valle, Marta; Roberto, Natalia; Domínguez-Clavé, Elisabet; Elices, Matilde; Luna, Luís Eduardo; Crippa, José Alexandre S; Hallak, Jaime E C; Araújo, Dráulio Barros de; Friedlander, Pablo; Barker, Steven A; Álvarez, Enrique; Soler, Joaquim; Pascual, Juan C; Feilding, Amanda; Riba, Jordi
BACKGROUND: Ayahuasca is a plant tea containing the psychedelic 5-HT2A agonist N,N-dimethyltryptamine and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network, purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here, we investigated in an open-label uncontrolled study in 16 healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications and their association with mindfulness measures. METHODS: Using 1H-magnetic resonance spectroscopy and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior and anterior cingulate cortex after a single ayahuasca dose. RESULTS: Magnetic resonance spectroscopy showed post-acute reductions in glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex. Connectivity was increased between the posterior cingulate cortex and the anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Glutamate+glutamine reductions correlated with increases in the "nonjudging" subscale of the Five Facets Mindfulness Questionnaire. Increased anterior cingulate cortex-medial temporal lobe connectivity correlated with increased scores on the self-compassion questionnaire. Post-acute neural changes predicted sustained elevations in nonjudging 2 months later. CONCLUSIONS: These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the posterior cingulate cortex, a key region within the default mode network, and increased connectivity between the anterior cingulate cortex and medial temporal lobe structures involved in emotion and memory potentially underlie the post-acute psychological effects of ayahuasca.
Assessing the psychedelic "after-glow" in ayahuasca users: post-acute neurometabolic and functional connectivity changes are associated with enhanced mindfulness capacities
(2017-06-13) Sampedro, Frederic; de la Fuente Revenga, Mario; Valle, Marta; Roberto, Natalia; Domínguez-Clavé, Elisabet; Elices, Matilde; Luna, Luís Eduardo; Crippa, José Alexandre S.; Hallak, Jaime E. C.; Araújo, Dráulio Barros de; Friedlander, Pablo; Barker, Steven A.; Álvarez, Enrique; Soler, Joaquim; Pascual, Juan C.; Feilding, Amanda; Riba, Jordi
BACKGROUND: Ayahuasca is a plant tea containing the psychedelic 5-HT2A agonist N,N-dimethyltryptamine (DMT) and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network (DMN), purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers, and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here we investigated in an open-label uncontrolled study in sixteen healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications, and their association with mindfulness measures. METHODS: Using 1H-magnetic resonance spectroscopy (MRS) and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior (PCC) and anterior (ACC) cingulate cortex after a single ayahuasca dose. RESULTS: MRS showed post-acute reductions in Glx (glutamate+glutamine), creatine and NAA-NAAG (N-acetylaspartate+N-acetylaspartylglutamate) in the PCC. Connectivity was increased between the PCC and the ACC, and between the ACC and limbic structures in the right medial temporal lobe (MTL). Glx reductions correlated with increases in the "Non-Judging" subscale of the Five Facets Mindfulness Questionnaire. Increased ACC-MTL connectivity correlated with increased scores on the Self-Compassion questionnaire. Post-acute neural changes predicted sustained elevations in "Non-Judging" two months later. CONCLUSIONS: These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the PCC, a key region within the DMN, and increased connectivity between the ACC and MTL structures involved in emotion and memory, potentially underlie the post-acute psychological effects of ayahuasca.
Auditory and visual stimuli in language mapping by functional MRI: is it modality specific?
(2012) Leoni, R. F.; Escorsi-Rosset, S.; Sakamoto, A. C.; Baffa, O.; Leite, J. P.; Santos, A. C.; Araújo, Dráulio Barros de
Human language is a complex process that involves specialized subsystems with certain modularity of organization. Mapping of language processing is of interest because of its social importance and clinical applications. Therefore, the purpose of the present study was to assess language processing using auditory and visual stimuli to determine if both stimulus modalities were robust for language mapping. Moreover, language lateralization was evaluated. Seventeen right handed asymptomatic subjects, native Portuguese speakers, performed a word generation task cued either by visual or auditory stimulus. As expected, language representation was mainly observed in the left frontal gyrus, including Broca’s area, left precentral and poscentral gyri, insula, and left superior temporal gyri, including Wernicke’s area, for both stimulus modalities. Other regions were also observed: bilateral cingulate and fusiform gyri; left parahippocampal, supramarginal and lingual gyri; thalamus, left parietal lobe and primary visual cortex. Laterality indices and centroids of these regions were not modality specific. Therefore, both stimulus modalities in combination with a simple verbal fluency task were robust for language mapping, allowing their application in different groups of patients.
Avaliação por ressonância magnética funcional e estimulação magnética transcraniana da intervenção única da terapia espelho em pacientes após acidente vascular cerebral isquêmico
(Universidade Federal do Rio Grande do Norte, 2012-08-24) Novaes, Morgana Menezes; Araújo, Dráulio Barros de; ; http://lattes.cnpq.br/7818012155694188; ; http://lattes.cnpq.br/9779330983275109; Santos, Antônio Carlos dos; ; http://lattes.cnpq.br/8227933586403761; Vargas, Cláudia Domingues; ; http://lattes.cnpq.br/1019505555117852
A Terapia Espelho (TE) vem sendo usada como ferramenta de reabilitação para várias doenças, incluindo o Acidente Vascular Cerebral (AVC). Embora alguns estudos tenham mostrado sua eficácia clínica, pouco se sabe sobre os mecanismos neurais que levam à melhora observada. Desse modo, este estudo teve como objetivo avaliar a neuromodulação cortical promovida pela intervenção única da TE em pacientes acometidos por AVC, por meio da Ressonância Magnética funcional (fMRI, do inglês Functional Magnetic Resonance Imaging) e da Estimulação Magnética Transcraniana (TMS, do inglês Transcranial Magnetic Stimulation). Quinze pacientes participaram de sessão única de trinta minutos de TE. Os dados de fMRI foram analisados nas seguintes regiões de interesse (ROI), bilateralmente: Área Motora Suplementar (AMS), córtex pré-motor (PM), córtex motor primário (M1), córtex sensorial primário (S1) e Cerebelo. Em cada ROI, as mudanças na porcentagem de ocupação e os valores de beta foram avaliados. Os resultados revelaram redução significativa no percentual de ocupação no PM e cerebelo contralateral à mão afetada (p <0,05). Além disso, foi observado aumento significativo nos valores de beta nas seguintes áreas motoras contralaterais: AMS, Cerebelo, PM e M1 (p <0,005) e diminuição significativa nas seguintes áreas motoras ipsilaterais: PM e M1 (p < 0,001). Nas áreas sensoriais foi observada redução em S1 bilateralmente (p <0,0005). Pela TMS foi analisado o Potencial Evocado Motor (PEM) sobre o hot spot de M1. Aumento significativo na amplitude do PEM foi observado após a terapia no grupo (p<0,0001), e individualmente em 4 pacientes (p <0,05). Assim, nossos resultados indicam que intervenção única da TE muda marcadores neurobiológicos em direção ao padrão observado em indivíduos saudáveis. Além disso, as alterações nas áreas motoras do hemisfério contralateral são opostas as do lado ipsilateral, sugerindo um aumento na homeostase do sistema.
Behavioral and EEG effects of GABAergic manipulation of the nigro-tectal pathway in the Wistar audiogenic rat (WAR) strain II: An EEG wavelet analysis and retrograde neuronal tracer approach
(2012-06-16) Rossetti, Franco; Rodrigues, Marcelo Cairrão Araújo; Marroni, Simone S.; Fernandes, Artur; Foresti, Maira Licia; Romcy-Pereira, Rodrigo Neves; Araújo, Dráulio Barros de; Garcia-Cairasco, Norberto
The role of the substantia nigra pars reticulata (SNPr) and superior colliculus (SC) network in rat strains susceptible to audiogenic seizures still remain underexplored in epileptology. In a previous study from our laboratory, the GABAergic drugs bicuculline (BIC) and muscimol (MUS) were microinjected into the deep layers of either the anterior SC (aSC) or the posterior SC (pSC) in animals of the Wistar audiogenic rat (WAR) strain submitted to acoustic stimulation, in which simultaneous electroencephalographic (EEG) recording of the aSC, pSC, SNPr and striatum was performed. Only MUS microinjected into the pSC blocked audiogenic seizures. In the present study, we expanded upon these previous results using the retrograde tracer Fluorogold (FG) microinjected into the aSC and pSC in conjunction with quantitative EEG analysis (wavelet transform), in the search for mechanisms associated with the susceptibility of this inbred strain to acoustic stimulation. Our hypothesis was that the WAR strain would have different connectivity between specific subareas of the superior colliculus and the SNPr when compared with resistant Wistar animals and that these connections would lead to altered behavior of this network during audiogenic seizures. Wavelet analysis showed that the only treatment with an anticonvulsant effect was MUS microinjected into the pSC region, and this treatment induced a sustained oscillation in the theta band only in the SNPr and in the pSC. These data suggest that in WAR animals, there are at least two subcortical loops and that the one involved in audiogenic seizure susceptibility appears to be the pSC-SNPr circuit. We also found that WARs presented an increase in the number of FG+projections from the posterior SNPr to both the aSC and pSC (primarily to the pSC), with both acting as proconvulsant nuclei when compared with Wistar rats. We concluded that these two different subcortical loops within the basal ganglia are probably a consequence of the WAR genetic background.
Behavioral and neuroimaging responses induced by mental imagery of threatening scenarios
(2016-10-15) Shuhama, Rosana; Rondinoni, Carlo; Araújo, Dráulio Barros de; Caetano, Gustavo de Freitas; Santos, Antonio Carlos dos; Graeff, Frederico Guilherme; Del-Ben, Cristina Marta
Functional neuroimaging studies have shown that actual situations of uncertain or distant threats increase the activity of forebrain regions, whereas proximal threats increase the activity of the dorsal midbrain. This experiment aimed at testing the hypothesis that brain activity elicited by imagined scenarios of threats with two different magnitudes, potential and imminent, resembles that found in response to actual threats. First, we measured subjective responses to imagined scenarios of potential and imminent threats compared with neutral and pleasant scenarios. The same scenarios were used as a paradigm in a functional magnetic resonance imaging experiment. Behavioral results show that the scenarios draw a gradient of hedonic valence and arousal dimensions. Both potential and imminent threat scenarios increased subjective anxiety; the imminent threat scenario also increased feelings of discomfort and bodily symptoms. The functional magnetic resonance imaging results revealed modulations of BOLD signal in the ventromedial prefrontal cortex by potential threat and in the periaqueductal gray matter by imminent threat. These results agree with previously reported evidence using actual threat situations, indicating that mental imagery is a reliable method for studying the functional neuroanatomy of relevant behavioral processes.
Brain complex network analysis by means of resting state fMRI and graph analysis: Will it be helpful in clinical epilepsy?
(2014) Onias, Heloisa; Viol, Aline; Palhano-Fontes, Fernanda; Andrade, Katia C.; Sturzbecher, Marcio; Viswanathan, Gandhimohan; Araújo, Dráulio Barros de
Functional magnetic resonance imaging (fMRI) has just completed 20 years of existence. It currently serves as a research tool in a broad range of human brain studies in normal and pathological conditions, as is the case of epilepsy. To date, most fMRI studies aimed at characterizing brain activity in response to various active paradigms. More recently, a number of strategies have been used to characterize the low-frequency oscillations of the ongoing fMRI signals when individuals are at rest. These datasets have been largely analyzed in the context of functional connectivity, which inspects the covariance of fMRI signals from different areas of the brain. In addition, resting state fMRI is progressively being used to evaluate complex network features of the brain. These strategies have been applied to a number of different problems in neuroscience, which include diseases such as Alzheimer's, schizophrenia, and epilepsy. Hence, we herein aimed at introducing the subject of complex network and how to use it for the analysis of fMRI data. This appears to be a promising strategy to be used in clinical epilepsy. Therefore, we also review the recent literature that has applied these ideas to the analysis of fMRI data in patients with epilepsy.

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