Abnormal Cortico-Cerebellar Functional Connectivity in Autism Spectrum Disorder

The cerebral cortex and the cerebellum are spatially remote areas that are connected by complex circuits that link both primary and associative areas. Previous studies have revealed abnormalities in autism spectrum disorder (ASD); however, it is not clear whether cortico-cerebellar connectivity is differentially manifested in the disorder. To explore this issue, we investigated differences in intrinsic cortico-cerebellar functional connectivity between individuals with typical development (TD) and those with ASD. To this end, we used functional magnetic resonance imaging (fMRI) of 708 subjects under a resting state protocol provided by the ABIDE I Consortium. We found that people with ASD had diminished functional connectivity between the cerebellum and the following cortical regions: (i) right fusiform gyrus, (ii) right postcentral gyrus, (iii) right superior temporal gyrus, (iv) right middle temporal gyrus, and (v) left middle temporal gyrus. All of these regions are involved in many cognitive systems that contribute to commonly affected functions in ASD. For right fusiform gyrus, right superior temporal gyrus, and left middle temporal gyrus, we reproduced the results in an independent cohort composed of 585 subjects of the ABIDE II Consortium. Our results points toward a consistent atypical cortico-cerebellar connectivity in ASD

From the Laboratory to the Classroom: The Potential of Functional Near-Infrared Spectroscopy in Educational Neuroscience

Paralleling two decades of growth in the emergent field known as educational neuroscience is an increasing concern that educational practices and programs should be evidence-based, however, the idea that neuroscience could potentially influence education is controversial. One of the criticisms, regarding applications of the findings produced in this discipline, concerns the artificiality of neuroscientific experiments and the oversimplified nature of the tests used to investigate cognitive processes in educational contexts. The simulations may not account for all of the variables present in real classroom activities. In this study, we aim to get a step closer to the formation of data-supported classroom methodologies by employing functional near-infrared spectroscopy in various experimental paradigms. First, we present two hyperscanning scenarios designed to explore realistic interdisciplinary contexts, i.e., the classroom. In a third paradigm, we present a case study of a single student evaluated with functional near-infrared spectroscopy and mobile eye-tracking glasses. These three experiments are performed to provide proofs of concept for the application of functional near-infrared spectroscopy in scenarios that more closely resemble authentic classroom routines and daily activities. The goal of our study is to explore the potential of this technique in hopes that it offers insights in experimental design to investigate teaching-learning processes during teacher-student interactions

Functional neural correlates of strategic memory processes in Mild Cognitive Impairment: an fMRI study

Introdução: Déficits de memória episódica constituem o marcador cognitivo mais frequente em pacientes com Comprometimento Cognitivo Leve (CCL).Estudos prévios mostram que déficits de memória episódica podem ser minimizados nestes pacientes por intervenções comportamentais. Entretanto, os mecanismos cerebrais envolvidos nos efeitos do treino cognitivo ainda são pouco explorados. O objetivo deste estudo foi avaliar o correlato neural por ressonância magnética funcional de um treino breve de memória em pacientes com CCL e compará-los com os achados em idosos saudáveis. Foram avaliados 18 pacientes com CCL e 19 idosos controles com a utilização de ressonância magnética funcional (RMf) em uma tarefa de codificação de listas de palavras com diferentes graus de relação semântica antes e após uma sessão de treino de estratégias de memória. Na sessão pré-treino, os participantes foram instruídos a memorizar as palavras durante a sessão de RMf sem qualquer orientação sobre o uso de estratégias de codificação. Após um treino breve no qual estratégias específicas de organização e agrupamento semântico foram exercitadas, os sujeitos foram reconduzidos ao aparelho de ressonância magnética e realizaram a sessão pós-treino, na qual foram instruídos a utilizar a estratégia treinada durante o paradigma de codificação de palavras. Os resultados dos exames de ressonância magnética funcional foram processados e analisados com o programa FSL versão 4.1. Ambos os grupos apresentaram aumento no número de palavras evocadas associado ao uso da estratégia treinada. Em ambos os grupos foi observado um aumento do sinal BOLD após o treino em regiões do córtex pré-frontal dorsolateral esquerdo e do córtex parietal bilateral. No grupo de idosos controles, entretanto, foi observada também uma redução da ativação em regiões do córtex parietal posterior esquerdo e cíngulo posterior bilateral, do córtex pré-frontal medial e cíngulo anterior direitos, do lóbulo parietal inferior e do córtex temporal superior direitos, do córtex pré-frontal dorsolateral direiro e do córtex óribito-frontal bilateral. A interação grupo x tempo foi significativa em áreas do córtex pré-frontal dorsolateral e ventromedial direitos. Estes resultado indicam que existem diferenças no recrutamento de regiões pré-frontais em resposta ao uso de estratégias de codificação em paradigmas de codificação de palavras entre pacientes com CCL e idosos cognitivamente saudáveisThe present studyinvestigated the effects of different applicationsof verbal learning strategies duringepisodicmemory encoding in patients with Mild Cognitive Impairment (MCI) (n=18) and normal controls (n=17) using functional magnetic resonance imaging (fMRI).The main goal of this study was to verify whether externally guided increases in verbal learning strategy application during episodic memory encoding modulate brain activity in memory-related networks in the same level in MCI as in controls. Participantswerescanned twice, using a word-list encoding fMRI paradigm.In the first session, self-initiated encoding strategies were used to intentionally memorize words during encoding. In the second session, participants received an explicit instruction to apply a semantic organization strategy (i.e. semantic clustering)to perform the task. The fMRI word list learning paradigm consisted of alternating blocks of encoding and resting baseline conditions. To perform the spontaneous fMRI session, participants were not instructed about the semantic organization of the words in the lists beforehand or given any practice with related lists. Therefore, any grouping by category observed in the subsequent free recall at the end of this fMRI acquisition was presumed to be self-initiated by the subject. At the end of the spontaneous session, each subject received a brief period of guidance or instructions to apply semantic strategies and organize words in terms of semantic categories during encoding, using a new set of word lists. Immediately after practicing the application of the strategy, participants were scanned again using the same type of paradigm as in the first session, except for the use of new set of word lists and the explicit instruction to apply semantic clustering.Free recall and strategic index scores were assessedafter each session. fMRI brain activation and deactivation during encoding of word lists in memory-related networks were examined across sessions. Results from the fMRI analysis revealed that after the explicit orientation to apply the verbal learning strategy, greater recruitment of frontoparietal network regions were observed in both MCI and control groups in relation to the unconstrained encoding condition. Group-differences in functional deactivations, however, were observed in the medial prefrontal (mPFC) cortex and in the right superior frontal gyrus, two critical nodes of the default mode network, related to the absence of modulation in the activity of the mPFC, along with a lack of suppression of the right superior frontal gyrus in MCI, in response to the increased use of the encoding strategy. A different association between improvement in strategy use and session-related changes in activation of the medial orbitalfrontal cortex between groups was also confirmed. That is, improvements in strategy use in controls contribute to a great extent in the amount of deactivation in OFC, whereas in patients, only a small portion of the increase in activation in this region was predicted by increases in strategy applicatio

Mem?ria contextual e estrat?gias de codifica??o em idosos com sintomas depressivos

Made available in DSpace on 2015-04-14T13:54:21Z (GMT). No. of bitstreams: 1 396638.pdf: 521558 bytes, checksum: ec4d92568e3b59d8308104132a32fef7 (MD5) Previous issue date: 2007-10-09A mem?ria contextual tem sido considerada um dos aspectos do funcionamento cognitivo mais suscept?vel aos efeitos nocivos do envelhecimento sobre a cogni??o. Tem sido demonstrado que estrat?gias de memoriza??o podem reverter os d?ficits de mem?ria contextual em idosos saud?veis. Entretanto, pouco se sabe do funcionamento desse tipo de mem?ria em uma prevalente parcela da popula??o de idosos: aquela que apresenta sintomas depressivos. Este trabalho teve por objetivo verificar os efeitos do envelhecimento associado a sintomas depressivos leves e do uso de estrat?gias de codifica??o sobre a mem?ria contextual. Para tanto, foram avaliados 22 adultos e 22 idosos sem sintomas depressivos, e 22 idosos com sintomas depressivos leves, rastreados pela Escala de Depress?o Geri?trica (GDS). Para caracterizar os grupos experimentais, o ritmo circadiano de cortisol dos participantes foi avaliado. O grupo de idosos com sintomas depressivos apresentou n?veis significativamente mais elevados de cortisol ?s 22 horas em rela??o aos demais grupos. Todos os grupos foram pareados em rela??o aos anos de estudo formal e em uma habilidade de intelig?ncia geral. Para a avalia??o da mem?ria, os sujeitos assistiram a uma s?ria de fotos de objetos distribu?dos em dois ambientes: uma sala de visitas e um escrit?rio. Metade dos sujeitos recebeu uma estrat?gia de codifica??o para o estabelecimento do v?nculo entre o objeto e o contexto e a outra metade recebeu uma instru??o n?o espec?fica. Ap?s um breve intervalo, os sujeitos realizaram testes de mem?ria de reconhecimento dos objetos e dos contextos. Os resultados revelaram que os idosos com sintomas depressivos leves n?o apresentaram preju?zos de mem?ria contextual em rela??o aos idosos controles. Entretanto, diferen?as foram observadas na magnitude do efeito produzido pela estrat?gia na mem?ria. Apenas os idosos controles apresentaram desempenho semelhante ao dos adultos na condi??o em que todos os grupos receberam a estrat?gia de codifica??o. Estes achados indicam que idosos com sintomas depressivos leves foram capazes de codificar atributos contextuais das informa??es, mas que os mesmos apresentaram certo tipo de preju?zo no uso de estrat?gias de memoriza??o

A review of Constraint-Induced Therapy applied to aphasia rehabilitation in stroke patients

Abstract Constraint-induced aphasia therapy (CIAT) is an intensive therapy model based on the forced use of verbal oral language as the sole channel of communication, while any alternative communication mode such as writing, gesturing or pointing are prevented. Objectives: This critical review involved the analysis of studies examining CIAT applied to stroke patients. Methods and Results: Using keywords, the Medline database was searched for relevant studies published between 2001 and 2008 (Medline 2001-2008). The critical evaluation of the articles was based on the classifications described by the ASNS (Cicerone adaptation). Two studies were categorized as level Ia, two as level II and one study as level IV. Conclusions: These recommendations should be interpreted with caution, given the small number of studies involved, but serve as a guideline for future studies in aphasia therapy

Non-neuronal evoked and spontaneous hemodynamic changes in the anterior temporal region of the human head may lead to misinterpretations of functional near-infrared spectroscopy signals

Several functional near-infrared spectroscopy (fNIRS) studies report their findings based on changes of a single chromophore, usually concentration changes of oxygenated hemoglobin ([[Formula: see text]]) or deoxygenated hemoglobin (HHb). However, influence of physiological actions may differ depending on which element is considered and the assumption that the chosen measure correlates with the neural response of interest might not hold. By assessing the correlation between [[Formula: see text]] and [HHb] in task-evoked activity as well as resting-state data, we identified a spatial dependency of non-neuronal hemodynamic changes in the anterior temporal region of the human head. Our findings support the importance of reporting and discussing fNIRS outcomes obtained with both chromophores ([[Formula: see text]] and [HHb]), in particular, for studies concerning the anterior temporal region of the human head. This practice should help to achieve a physiologically correct interpretation of the results when no measurements with short-distance channels are available while employing continuous-wave fNIRS systems