Navegando por Autor "Copelli, Mauro"

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Análise de grafos de textos literários: investigação de traços psicóticos
(2016-09-30) Pinheiro, Sylvia Galvão de Vasconcelos; Ribeiro, Sidarta Tollendal Gomes; ; http://lattes.cnpq.br/0649912135067700; ; http://lattes.cnpq.br/3289718915118012; Queiroz, Cláudio Marcos Teixeira de; ; http://lattes.cnpq.br/3384801391828521; Copelli, Mauro; ; Queiroz, Alvaro José Magalhães de;
Estudos recentes em psiquiatria computacional (Mota et al., 2012; Mota et al., 2014, Mota et al., em preparação) apontam diferenças estruturais significativas entre os discursos de pacientes com psicose e de sujeitos saudáveis. A análise de grafos de relatos destes sujeitos permite quantificar sintomas da psicose esquizofrênica, caracterizada por fala pobre, repetitiva e com baixa conectividade entre as palavras. Com base numa reinterpretação literal de textos históricos, Julian Jaynes propôs que a psicose foi socialmente prevalente até cerca de 1.000 anos a.C (Jaynes, 1976). Esta conjectura foi corroborada pela primeira vez por Diuk et al. (2012), que utilizaram análise de semântica latente para demonstrar que o nível de similaridade com o conceito de introspecção cresce com o tempo em textos judaico-cristãos e greco-romanos do último milênio a.C. Neste trabalho buscamos investigar a hipótese de que textos da Antiguidade são estruturalmente mais semelhantes a relatos de psicóticos do que a relatos de sujeitos saudáveis. Para isso, investigamos atributos de grafo em 448 textos históricos, datados de 3000 a.C. a 2010 d.C compreendendo seis diferentes tradições da Eurásia (Siro-Mesopotâmica, Egípcia, Hindu, Persa, Judaico-Cristã, Greco-Romana) e três grupos de literatura mais recente (Medieval, Moderna, Contemporânea). Um total de 14 atributos de grafo foi estudado, compreendendo diversidade lexical (número de nós), conectividade (arestas, maior componente conectado, maior componente fortemente conectado), recorrência (arestas repetidas, arestas paralelas, ciclos de 1, 2 ou 3 nós) e atributos globais (grau médio total, diâmetro, densidade, média dos caminhos mínimos, e coeficiente de aglomeramento). Os resultados revelaram um padrão claro de aumento assintótico da diversidade de palavras e de conectividade, com diminuição das recorrências ao longo do tempo. Os resultados são compatíveis com a teoria de que a psicose é um traço ancestral da espécie humana.
Automated analysis of free speech predicts psychosis onset in high-risk youths
(Nature, 2015-08-26) Bedi, Gillinder; Carrillo, Facundo; Cecchi, Guillermo A; Slezak, Diego Fernández; Sigman, Mariano; Mota, Natália B; Ribeiro, Sidarta Tollendal Gomes; Javitt, Daniel C; Copelli, Mauro; Corcoran, Cheryl M
Avaliação quantitativa da introspecção na literatura histórica e sua associação a grafos
(Universidade Federal do Rio Grande do Norte, 2021-03-01) Silva, Marina Tatiane Ribeiro da; Ribeiro, Sidarta Tollendal Gomes; ; http://lattes.cnpq.br/0649912135067700; ; http://lattes.cnpq.br/8146595829494576; Araújo, Draulio Barros de; ; http://lattes.cnpq.br/7818012155694188; Copelli, Mauro; ; http://lattes.cnpq.br/9400915429521069
Variações temporais de introspecção já foram associadas à mudança da forma do pensamento. Em especial, a Era Axial (período de 800 BC a 200 BC), supostamente denota um período de transição entre uma mente bicameral para uma mente mais reflexiva. Outros argumentam que o período é caracterizado meramente por desenvolvimento sócio-econômico, em vez de mudança de mentalidade. Uma mente bicameral seria caracterizada por alucinações auditivas, vozes interiores associadas a agentes externos, como deuses moralizadores no lugar de vontade própria. Tais respostas auditivas são expressas em pacientes diagnosticados com esquizofrenia, que também podem apresentar pouca conectividade na fala, conhecida como desordem da forma do pensamento, que seria o pensamento “descarrilhado” apresentado na fala. A baixa conectividade é exibida pela Recorrência de Longo Alcance, a habilidade de conectar o contexto atual com algo que foi dito anteriormente. Em grafos não-semânticos, a Recorrência de Longo Alcance é representada pelo Maior Componente Fortemente Conectado. Dessa maneira, não é exagero assumir que ambos, baixa conectividade e introspecção, poderiam estar associados a variações na forma do pensamento. Alguns estudos mostram o efeito da educação sobre a baixa conectividade, inclusive, sugerem que este atributo da fala teria amadurecido durante a Era Axial, apoiando, assim, a hipótese de uma mudança de mentalidade durante o período. Outra hipótese seria a de que a transição entre tradições orais para alfabetização estaria intrinsecamente ligada à uma transição de menor para maior introspecção, respectivamente. Além disso, o uso computacional do Processamento de Linguagem Natural, como Análise Semântica Latente, permitiu uma medida quantitativa de introspecção em textos das tradições Judaico-Cristãs, Greco-Romanas e da Era Moderna. Portanto, propomos a análise quantitativa de introspecção em textos de 9 tradições históricas (≥ 4500 anos), além de sua evolução temporal e relação com a conectividade da fala. Com o uso de Análise Semântica Latente e grafos não-semânticos, nossos resultados mostram que mudanças de introspecção ocorreram durante a Era Axial e outros períodos caracterizados por desenvolvimento econômico. No mais, a introspecção tem uma relação direta com a Recorrência de Longo Alcance, sugerindo que variações na linguagem estão associadas a mudanças na introspecção e na maneira de pensar.
Characterization of the relationship between semantic and structural language features in psychiatric diagnosis
(IEEE, 2017-04) Mota, Natália; Ribeiro, Sidarta Tollendal Gomes; Copelli, Mauro; Carrillo, Fernando; Slezak, Diego Fernadez
Psychiatry describes speech symptoms that are indicative of disorganized thought, but measuring them is not easy. With natural language processing tools, it is possible to quantify psychiatric symptoms. Graph representations of word trajectories and semantic incoherence have independently been shown to predict the Schizophrenia diagnosis. Both analyses assess thought organization through speech, but the relationship between them is unknown. To fill this gap, here we characterize the relationship between structural and semantic features of free verbal reports from 60 patients and matched controls. Graph connectedness is inversely correlated to semantic incoherence and both explain 54% of negative symptoms variance
Computational Tracking of Mental Health in Youth: Latin American Contributions to a Low-Cost and Effective Solution for Early Psychiatric Diagnosis
(2016-06) Mota, Natalia Bezerra; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
The early onset of mental disorders can lead to serious cognitive damage, and timely interventions are needed in order to prevent them. In patients of low socioeconomic status, as is common in Latin America, it can be hard to identify children at risk. Here, we briefly introduce the problem by reviewing the scarce epidemiological data from Latin America regarding the onset of mental disorders, and discussing the difficulties associated with early diagnosis. Then we present computational psychiatry, a new field to which we and other Latin American researchers have contributed methods particularly relevant for the quantitative investigation of psychopathologies manifested during childhood. We focus on new technologies that help to identify mental disease and provide prodromal evaluation, so as to promote early differential diagnosis and intervention. To conclude, we discuss the application of these methods to clinical and educational practice. A comprehensive and quantitative characterization of verbal behavior in children, from hospitals and laboratories to homes and schools, may lead to more effective pedagogical and medical intervention
Criticality between Cortical States
(2019-05-21) Fontenele, Antonio J.; Vasconcelos, Nivaldo A. P. de; Feliciano, Thaís; Aguiar, Leandro A. A.; Soares-Cunha, Carina; Coimbra, Bárbara; Porta, Leonardo Dalla; Ribeiro, Sidarta Tollendal Gomes; Rodrigues, Ana João; Sousa, Nuno; Carelli, Pedro V.; Copelli, Mauro
Since the first measurements of neuronal avalanches, the critical brain hypothesis has gained traction. However, if the brain is critical, what is the phase transition? For several decades, it has been known that the cerebral cortex operates in a diversity of regimes, ranging from highly synchronous states (with higher spiking variability) to desynchronized states (with lower spiking variability). Here, using both new and publicly available data, we test independent signatures of criticality and show that a phase transition occurs in an intermediate value of spiking variability, in both anesthetized and freely moving animals. The critical exponents point to a universality class different from mean-field directed percolation. Importantly, as the cortex hovers around this critical point, the avalanche exponents follow a linear relation that encompasses previous experimental results from different setups and is reproduced by a model.
Um estudo da evolução da mente e das psicopatologias através da análise de grafos da literatura
(2014-09) Pinheiro, Sylvia; Mota, Natália; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
Introdução Para melhor compreender pacientes com psicopatologias, Mota e colaboradores (2012, 2014) investigaram atributos de grafos de entrevistas obtidas de pacientes com esquizofrenia, com transtorno bipolar tipo I e em controles não psicóticos O estudo aponta a possibilidade de um estudo psiquiátrico quantitativo, e mostra diferenças significativas entre indivíduos bipolares e esquizofrênicos em pelo menos 10 atributos de grafos. Em uma análise de classificadores, os atributos permitiram uma diferenciação com alta sensibilidade e especificidade. Também realizando análise de texto, porém numa vertente semântica, Diuk e colaboradores (2012) aplicaram a ferramenta LSA (Latent Semantic Analysis) para estimar a presença do conceito de “introspecção” durante uma janela da história do desenvolvimento humano. Este trabalho, baseado nas ideias de Julian Jaynes (1976), encontrou na transição da tradição popular oral para a escrita durante a chamada Era Axial, (período 800 a.C. a 200 a.C.) um aumento dos níveis de introspecção. O estudo utilizou textos antigos das culturas grecoromana e judaicocristã, além de textos da atualidade. Os resultados corroboram a teoria de Jaynes sobre o aparecimento recente da consciência humana atual, através da ruptura do modo de funcionamento mental conhecido como “bicameral”. Este é caracterizado pela ausência de introspecção e constante intervenção de “vozes”, comportamento que é similar ao de indivíduos psicóticos. Objetivos Inspirandose nestas ideias, nosso estudo busca aplicar análise de grafos à literatura, em duas vertentes: 1) análise dos textos de escritores historicamente diagnosticados como psicóticos na literatura moderna e contemporânea; 2) análise dos textos da Era Axial. Métodos Para isto, obtivemos a versão digital das obras literárias no domínio púbico da internet, (em sítios como o Projeto Gutenberg e MIT Classics) e os adequamos para a versão de texto. Utilizamos o software Speechgraphs, que calcula atributos diversos baseandose na teoria dos grafos e posteriormente, pretendemos construir classificadores através do software Weka. Resultados e Conclusões Na primeira vertente de estudo, encontramos diferenças significativas entre os indivíduos esquizofrênicos e os controles, no atributo de grafo Arestas (12,76, p=0,0167**, N=34 autores), para janelas de 100 palavras, e em dois atributos (Arestas: 12,65; p= 0,0216* LSC: 10,39, p=0,0546*, N=34 autores) para janelas de 30 palavras , mostrando consistência com os estudos anteriores de Mota et al (2012, 2014). Na segunda linha, encontramos diferenças em quase todos os atributos de grafo quando comparamos o Antigo Testamento ao Novo Testamento e às Confissões de Santo Agostinho, todos textos da tradição judaicocristã. Com o desenvolvimento desta pesquisa com mais autores contemporâneos e a inclusão de textos da tradição grecoromana, esperamos aprofundar o teste de nossas hipóteses sobre padrões já encontrados para indivíduos com psicopatologias, e também encontrar novas evidências do padrão de comportamento bicameral.
Graph analysis of dream reports is especially informative about psychosis
(2014-01-15) Mota, Natália B.; Furtado, Raimundo; Maia, Pedro P. C.; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
Early psychiatry investigated dreams to understand psychopathologies. Contemporary psychiatry, which neglects dreams, has been criticized for lack of objectivity. In search of quantitative insight into the structure of psychotic speech, we investigated speech graph attributes (SGA) in patients with schizophrenia, bipolar disorder type I, and non-psychotic controls as they reported waking and dream contents. Schizophrenic subjects spoke with reduced connectivity, in tight correlation with negative and cognitive symptoms measured by standard psychometric scales. Bipolar and control subjects were undistinguishable by waking reports, but in dream reports bipolar subjects showed significantly less connectivity. Dream-related SGA outperformed psychometric scores or waking-related data for group sorting. Altogether, the results indicate that online and offline processing, the two most fundamental modes of brain operation, produce nearly opposite effects on recollections: While dreaming exposes differences in the mnemonic records across individuals, waking dampens distinctions. The results also demonstrate the feasibility of the differential diagnosis of psychosis based on the analysis of dream graphs, pointing to a fast, low-cost and language-invariant tool for psychiatric diagnosis and the objective search for biomarkers. The Freudian notion that “dreams are the royal road to the unconscious” is clinically useful, after all.
Graph analysis of verbal fluency test discriminate between patients with Alzheimer’s disease, Mild Cognitive Impairment and normal elderly controls
(2014-06-17) Bertola, Laiss; Mota, Natalia Bezerra; Copelli, Mauro; Rivero, Thiago; Diniz, Breno Satler de Oliveira; Romano-Silva, Marco Aurelio; Ribeiro, Sidarta Tollendal Gomes; Malloy-Diniz, Leandro Fernandes
Graph theory applied to speech: insights on cognitive deficit diagnosis and dream research
(2018) Mota, Natália Bezerra; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
In the past ten years, graph theory has been widely employed in the study of natural and technological phenomena. The representation of the relationships among the units of a network allow for a quantitative analysis of its overall structure, beyond what can be understood by considering only a few units. Here we discuss the application of graph theory to psychiatric diagnosis of psychoses and dementias. The aim is to quantify the flow of thoughts of psychiatric patients, as expressed by verbal reports of dream or waking events. This flow of thoughts is hard to measure but is at the roots of psychiatry as well as psychoanalysis. To this end, speech graphs were initially designed with nodes representing lexemes and edges representing the temporal sequence between consecutive words, leading to directed multigraphs. In a subsequent study, individual words were considered as nodes and their temporal sequence as edges; this simplification allowed for the automatization of the process, effected by the free software Speech Graphs. Using this approach, one can calculate local and global attributes that characterize the network structure, such as the total number of nodes and edges, the number of nodes present in the largest connected and the largest strongly connected components, measures of recurrence such as loops of 1, 2, and 3 nodes, parallel and repeated edges, and global measures such as the average degree, density, diameter, average shortest path, and clustering coefficient. Using these network attributes we were able to automatically sort schizophrenia and bipolar patients undergoing psychosis, and also to separate these psychotic patients from subjects without psychosis, with more than 90% sensitivity and specificity. In addition to the use of the method for strictly clinical purposes, we found that differences in the content of the verbal reports correspond to structural differences at the graph level. When reporting a dream, healthy subjects without psychosis and psychotic subjects with bipolar disorder produced more complex graphs than when reporting waking activities of the previous day; this difference was not observed in psychotic subjects with schizophrenia, which produced equally poor reports irrespective of the content. As a consequence, graphs of dream reports were more efficient for the differential diagnosis of psychosis than graphs of daily reports. Based on these results we can conclude that graphs from dream reports are more informative about mental states, echoing the psychoanalytic notion that dreams are a privileged window into thought.
Imagetic and affective measures of memory reverberation diverge at sleep onset in association with theta rhythm
(Elsevier BV, 2022-10) Mota, Natália Bezerra; Soares, Ernesto Saias; Altszyler, Edgar; Sánchez-Gendriz, Ignacio; Muto, Vincenzo; Heib, Dominik; Slezak, Diego F.; Sigman, Mariano; Copelli, Mauro; Schabus, Manuel; Ribeiro, Sidarta Tollendal Gomes
The 'day residue' - the presence of waking memories into dreams - is a century-old concept that remains controversial in neuroscience. Even at the psychological level, it remains unclear how waking imagery cedes into dreams. Are visual and affective residues enhanced, modified, or erased at sleep onset? Are they linked, or dissociated? What are the neural correlates of these transformations? To address these questions we combined quantitative semantics, sleep EEG markers, visual stimulation, and multiple awakenings to investigate visual and affect residues in hypnagogic imagery at sleep onset. Healthy adults were repeatedly stimulated with an affective image, allowed to sleep and awoken seconds to minutes later, during waking (WK), N1 or N2 sleep stages. 'Image Residue' was objectively defined as the formal semantic similarity between oral reports describing the last image visualized before closing the eyes ('ground'), and oral reports of subsequent visual imagery ('hypnagogic imagery). Similarly, 'Affect Residue' measured the proximity of affective valences between 'ground' and 'hypnagogic imagery'. We then compared these grounded measures of two distinct aspects of the 'day residue', calculated within participants, to randomly generated values calculated across participants. The results show that Image Residue persisted throughout the transition to sleep, increasing during N1 in proportion to the time spent in this stage. In contrast, the Affect Residue was gradually neutralized as sleep progressed, decreasing in proportion to the time spent in N1 and reaching a minimum during N2. EEG power in the theta band (4.5-6.5 Hz) was inversely correlated with the Image Residue during N1. The results show that the visual and affective aspects of the 'day residue' in hypnagogic imagery diverge at sleep onset, possibly decoupling visual contents from strong negative emotions, in association with increased theta rhythm
Investigação in silico do mecanismo de reorganização sináptica do sono. Um algoritmo para maximizar a capacidade computacional de redes neurais esparsas
(Universidade Federal do Rio Grande do Norte, 2021-11-09) Silva, Ana Cláudia Costa da; Ribeiro, Sidarta Tollendal Gomes; Costa, César Renno; 22508952877; http://lattes.cnpq.br/9222565820639401; http://lattes.cnpq.br/0649912135067700; http://lattes.cnpq.br/4555593159788385; Dalmolin, Rodrigo Juliani Siqueira; http://lattes.cnpq.br/4065178015615979; Mohan, Madras Viswanathan Gandhi; http://lattes.cnpq.br/1995273890709490; Copelli, Mauro; http://lattes.cnpq.br/9400915429521069; Vasconcelos, Nivaldo Antônio Portela de; http://lattes.cnpq.br/4110109220389767
As memórias são armazenadas no cérebro pela mudança persistente da conectividade entre neurônios e o sono desempenha um papel decisivo para a persistência dessas mudanças. Pesquisas sobre a neurobiologia do sono demonstram a ativação de mecanismos de plasticidade sináptica de longa duração. Dados experimentais apontam para um duplo papel do sono, tanto no esquecimento de memórias irrelevantes quanto no reforço das lembranças mais importantes. A hipótese investigada nesta tese é de que os mecanismos de reorganização sináptica envolvidos na consolidação de memórias podem trazer vantagens na performance das redes neurais artificiais. Este trabalho visa aplicar mecanismos neurobiológicos de aprendizagem dependente de sono na aprendizagem de máquina. Para isto, foi feita uma revisão das teorias de consolidação da memória através do sono, assim como dos modelos computacionais que dão suporte a essas teorias. Com a observação de como o cérebro otimiza os recursos biológicos, a pesquisa seguiu a tendência das redes neurais artificiais onde foram aplicados conceitos presentes na aprendizagem biológica, na aprendizagem de máquina. Então foram realizadas simulações de computador para explorar a hipótese de que os mecanismos subjacentes utilizados pelo cérebro para aprendizagem biológica através do sono são capazes de otimizar o aprendizado em redes neurais artificiais. A esparsialidade sináptica pode trazer vantagens na economia de recursos sem que haja um decaimento na aprendizagem, então, usamos uma rede neural artificial esparsa para aprender diferentes conjuntos de dados e, em seguida, testar se o sono poderia reduzir ainda mais o número mínimo de sinapses que um sistema precisa para o aprendizado de padrões. As simulações foram realizadas com diferentes tamanhos de rede, diferentes níveis de esparsialidades, diversas bases de dados além de utilizar modernos frameworks e algoritmos em aprendizagem de redes neurais profundas. Os resultados corroboram a hipótese de que o sono reduz o número necessário de sinapses para que se atinja um determinado limite de aprendizagem.
A Naturalistic Assessment of the Organization of Children’s Memories Predicts Cognitive Functioning and Reading Ability
(2016-08-02) Mota, Natália Bezerra; Weissheimer, Janaína; Madruga, Beatriz; Adamy, Nery; Bunge, Silvia A.; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
To explore the relationship between memory and early school performance, we used graph theory to investigate memory reports from 76 children aged 6–8 years. The reports comprised autobiographical memories of events days to years past, and memories of novel images reported immediately after encoding. We also measured intelligence quotient (IQ) and theory of mind (ToM). Reading and Mathematics were assessed before classes began (December 2013), around the time of report collection (June 2014), and at the end of the academic year (December 2014). IQ and ToM correlated positively with word diversity and word-to-word connectivity, and negatively with word recurrence. Connectivity correlated positively with Reading in June 2014 as well as December 2014, even after adjusting for IQ and ToM. To our knowledge, this is the first study demonstrating a link between the structure of children’s memories and their cognitive or academic performance.
Physiology and assessment as low-hanging fruit for education overhaul
(Springer, 2017-03-27) Ribeiro, Sidarta Tollendal Gomes; Mota, Natalia; Fernandes, Valter R.; Deslandes, Andrea Camaz; Brockington, Guilherme; Copelli, Mauro
Physiology and assessment constitute major bottlenecks of school learning among students with low socioeconomic status. The limited resources and household overcrowding typical of poverty produce deficits in nutrition, sleep, and exercise that strongly hinder physiology and hence learning. Likewise, overcrowded classrooms hamper the assessment of individual learning with enough temporal resolution to make individual interventions effective. Computational measurements of learning offer hope for low-cost, fast, scalable, and yet personalized academic evaluation. Improvement of school schedules by reducing lecture time in favor of naps, exercise, meals, and frequent automated assessments of individual performance is an easily achievable goal for education.
Post-class naps boost declarative learning in a naturalistic school setting
(2018-08-21) Cabral, Thiago; Mota, Natália B.; Fraga, Lucia; Copelli, Mauro; McDaniel, Mark A.; Ribeiro, Sidarta Tollendal Gomes
Laboratory evidence of a positive effect of sleep on declarative memory consolidation suggests that naps can be used to boost school learning in a scalable, low-cost manner. The few direct investigations of this hypothesis have so far upheld it, but departed from the naturalistic setting by testing non-curricular contents presented by experimenters instead of teachers. Furthermore, nap and non-nap groups were composed of different children. Here we assessed the effect of post-class naps on the retention of Science and History curricular contents presented by the regular class teacher to 24 students from 5th grade. Retention was repeatedly measured 3–4 days after content learning, with weekly group randomization over 6 consecutive weeks. Contents followed by long naps (>30 min), but not short naps (<30 min), were significantly more retained than contents followed by waking (Cohen’s d = 0.7962). The results support the use of post-class morning naps to enhance formal education.
Psychosis and the Control of Lucid Dreaming
(Universidade Federal do Rio Grande do Norte, 2016) Mota, Natália B.; Resende, Adara; Mota-Rolim, Sérgio A.; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
Dreaming and psychosis share important features, such as intrinsic sense perceptions independent of external stimulation, and a general lack of criticism that is associated with reduced frontal cerebral activity. Awareness of dreaming while a dream is happening defines lucid dreaming (LD), a state in which the prefrontal cortex is more active than during regular dreaming. For this reason, LD has been proposed to be potentially therapeutic for psychotic patients. According to this view, psychotic patients would be expected to report LD less frequently, and with lower control ability, than healthy subjects. Furthermore, psychotic patients able to experience LD should present milder psychiatric symptoms, in comparison with psychotic patients unable to experience LD. To test these hypotheses, we investigated LD features (occurrence, control abilities, frequency, and affective valence) and psychiatric symptoms (measure by PANSS, BPRS, and automated speech analysis) in 45 subjects with psychotic symptoms [25 with Schizophrenia (S) and 20 with Bipolar Disorder (B) diagnosis] versus 28 non-psychotic control (C) subjects. Psychotic lucid dreamers reported control of their dreams more frequently (67% of S and 73% of B) than non-psychotic lucid dreamers (only 23% of C; S > C with p = 0.0283, B > C with p = 0.0150). Importantly, there was no clinical advantage for lucid dreamers among psychotic patients, even for the diagnostic question specifically related to lack of judgment and insight. Despite some limitations (e.g., transversal design, large variation of medications), these preliminary results support the notion that LD is associated with psychosis, but falsify the hypotheses that we set out to test. A possible explanation is that psychosis enhances the experience of internal reality in detriment of external reality, and therefore lucid dreamers with psychotic symptoms would be more able to control their internal reality than non-psychotic lucid dreamers. Training dream lucidity is likely to produce safe psychological strengthening in a non-psychotic population, but in a psychotic population LD practice may further empower deliria and hallucinations, giving internal reality the appearance of external reality.
Repertoires of Spike Avalanches Are Modulated by Behavior and Novelty
(Universidade Federal do Rio Grande do Norte, 2016) Ribeiro, Tiago L.; Ribeiro, Sidarta Tollendal Gomes; Copelli, Mauro
Neuronal avalanches measured as consecutive bouts of thresholded field potentials represent a statistical signature that the brain operates near a critical point. In theory, criticality optimizes stimulus sensitivity, information transmission, computational capability and mnemonic repertoires size. Field potential avalanches recorded via multielectrode arrays from cortical slice cultures are repeatable spatiotemporal activity patterns. It remains unclear whether avalanches of action potentials observed in forebrain regions of freely-behaving rats also form recursive repertoires, and whether these have any behavioral relevance. Here, we show that spike avalanches, recorded from hippocampus (HP) and sensory neocortex of freely-behaving rats, constitute distinct families of recursive spatiotemporal patterns. A significant number of those patterns were specific to a behavioral state. Although avalanches produced during sleep were mostly similar to others that occurred during waking, the repertoire of patterns recruited during sleep differed significantly from that of waking. More importantly, exposure to novel objects increased the rate at which new patterns arose, also leading to changes in post-exposure repertoires, which were significantly different from those before the exposure. A significant number of families occurred exclusively during periods of whisker contact with objects, but few were associated with specific objects. Altogether, the results provide original evidence linking behavior and criticality at the spike level: spike avalanches form repertoires that emerge in waking, recur during sleep, are diversified by novelty and contribute to object representation
Rumo ao cultivo ecológico da mente
(2016-11) Ribeiro, Sidarta Tollendal Gomes; Mota, Natalia; Copelli, Mauro
Em estudantes de baixo nível socioeconômico, o aprendizado escolar é diretamente prejudicado pelas importantes limitações fisiológicas que tipicamente acompanham a pobreza, bem como pela baixa qualidade de avaliação do aprendizado individual. A escassez de recursos e a superlotação de residências produzem déficits de nutrição, sono e exercício físico que prejudicam a aprendizagem por meio de mecanismos fisiológicos bem conhecidos mas pouco considerados no ambiente escolar. A superlota- ção das salas de aula, por outro lado, prejudica a avaliação fidedigna e suficientemente frequente da aprendizagem individual, capaz de informar intervenções focadas nas dificuldades especí- ficas de cada aluno. Testes automatizados do aprendizado por meio da análise matemática do discurso e de jogos computacionais constituem alternativas de baixo custo, rápidas e escaláveis para personalizar e qualificar a avaliação acadê- mica. As metas essenciais de uma nova educa- ção, capaz de efetivamente minorar a distância entre ricos e pobres, devem incluir a otimiza- ção dos horários escolares através da redução do tempo de aulas em favor de regimes otimizados de sonecas, exercícios físicos e refeições, bem como avaliações automáticas frequentes do desempenho individual, que motivem interven- ções específicas baseadas em déficits avaliados não pelas curvas médias de aprendizagem entre vários alunos, calculadas ocasionalmente, mas por curvas de aprendizagem individuais atualizadas diariamente. Estas estratégias podem ser combinadas para reforçar positivamente, minutos após sua detecção, as mudanças cognitivas observadas em alunos específicos. Assim como a agricultura ecológica promove a rotação inteligente de culturas e insumos, é preciso construir um novo modelo de “educação ecológica” em que os alunos possam ciclar por diferentes estágios de aquisição e consolidação da memória, reduzindo a superlotação das salas de aula sem custos adicionais e contribuindo potencialmente para nivelar gradientes educacionais em todo o planeta.
Speech structure links the neural and socio-behavioural correlatesof psychotic disorders
(2018-07-08) Palaniyappan, Lena; Mota, Natália Bezerra; Oowise, Shamuz; Balain, Vijender; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes; Liddle, Peter
Background: A longstanding notion in the concept of psychosis is the prominence of loosened associative links in thought processes. Assessment of such subtle aspects of thought disorders has proved to be a challenging task in clinical practice and to date no surrogate markers exist that can reliably track the physiological effects of treatments that could reduce thought disorders. Recently, automated speech graph analysis has emerged as a promising means to reliably quantify structural speech disorganization. Methods: Using structural and functional imaging, we investigated the neural basis and the functional relevance of the structural connectedness of speech samples obtained from 56 patients with psychosis (22 with bipolar disorder, 34 with schizophrenia). Speech structure was assessed by non-semantic graph analysis. Results: We found a canonical correlation linking speech connectedness and i) functional as well as developmentally relevant structural brain markers (degree centrality from resting state functional imaging and cortical gyrification index) ii) psychometric evaluation of thought disorder iii) aspects of cognitive performance (processing speed deficits) and iv) functional outcome in patients. Of various clinical metrics, only speech connectedness was correlated with biological markers. Speech connectedness filled the dynamic range of responses better than psychometric measurements of thought disorder. Conclusions: The results provide novel evidence that speech dysconnectivity could emerge from neurodevelopmental deficits and associated dysconnectivity in psychosis.
The graph properties of psychotic speech differ between early and late onset, but not between acute and chronic psychosis.
(2014-09) Mota, Natália Bezerra; Copelli, Mauro; Ribeiro, Sidarta Tollendal Gomes
Introdução Speech structure measured by graph analysis can help clinicians to quantify speech symptoms, and characterize the psychopathology of psychosis. One important feature observed by psychiatrists are the different aspects of early and late onset psychosis with regard to cognitive symptoms. Since larger cognitive deficits are expected in the population with early onset psychosis, early diagnosis is important to guide interventions able to mitigate a more severe evolution of the disease. Objetivos The aim of the present study is to identify the influence on different types of psychosis (schizophrenia or bipolar disorder) of different types of onset (early onset: psychosis before age 18, late onset: after age 18) and different disease durations (during first episode psychosis or chronic psychosis, after two years of disease). Métodos We interviewed 52 psychotic subjects, applying psychometric scales and asking for dream reports. Then we transcribed those reports, represented as wordgraphs (each word was represented as a node, and the temporal link between consecutive words was represented as an edge) and quantified 14 speech graph attributes (SGAs) after controlling for differences in word count. Resultados e Conclusões We performed a threeway ANOVA to predict the influence of age of onset (early or late), duration of disease (first episode psychosis or chronic) and diagnosis (schizophrenia and bipolar disorder), considering 3 different types of interaction (onset x duration, onset x diagnosis, duration x diagnosis), and correcting for 3 comparisons (α=0.0167). Diagnosis is related with differences in edges (p=0.0001), LCC (p=0.0002), LSC (p=0.0001), and ATD (p=0.0046); onset is related with differences in L1 (p=0.0091) and the interaction of diagnosis and onset is related to differences in ATD (p=0.0155). We also found a positive correlation between selfloops and age of onset (RHO=0.3992, p=0.0034), but no correlation was detected between standard psychometric measures and duration of disease or age of onset. The late onset group showed more selfloops than the early onset group (p=0.0308), and the late onset schizophrenia group showed a smaller ATD than the early onset schizophrenia group (p=0.0489). Conclusion: Selfloops measured on graphs of dream reports are better correlated with age of onset than standard psychometric measures, characterizing differences between early and late onset psychotic groups. We also found that early onset schizophrenia, but not bipolar psychosis, shows higher ATD than late onset schizophrenia. We did not find correlations between SGAs and duration of disease, or interactions between duration and onset or diagnosis to explain SGAs differences, pointing to the conclusion that SGAs must be a trace, more than a stage metric of psychotic speech.

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Navegando por Autor "Copelli, Mauro"