Dynamic Reorganization of Functional Connectivity Reveals Abnormal Temporal Efficiency in Schizophrenia.

Emerging evidence suggests that schizophrenia is associated with brain dysconnectivity. Nonetheless, the implicit assumption of stationary functional connectivity (FC) adopted in most previous resting-state functional magnetic resonance imaging (fMRI) studies raises an open question of schizophrenia-related aberrations in dynamic properties of resting-state FC. This study introduces an empirical method to examine the dynamic functional dysconnectivity in patients with schizophrenia. Temporal brain networks were estimated from resting-state fMRI of 2 independent datasets (patients/controls = 18/19 and 53/57 for self-recorded dataset and a publicly available replication dataset, respectively) by the correlation of sliding time-windowed time courses among regions of a predefined atlas. Through the newly introduced temporal efficiency approach and temporal random network models, we examined, for the first time, the 3D spatiotemporal architecture of the temporal brain network. We found that although prominent temporal small-world properties were revealed in both groups, temporal brain networks of patients with schizophrenia in both datasets showed a significantly higher temporal global efficiency, which cannot be simply attributable to head motion and sampling error. Specifically, we found localized changes of temporal nodal properties in the left frontal, right medial parietal, and subcortical areas that were associated with clinical features of schizophrenia. Our findings demonstrate that altered dynamic FC may underlie abnormal brain function and clinical symptoms observed in schizophrenia. Moreover, we provide new evidence to extend the dysconnectivity hypothesis in schizophrenia from static to dynamic brain network and highlight the potential of aberrant brain dynamic FC in unraveling the pathophysiologic mechanisms of the disease

Scientific Reports / The tactile window to consciousness is characterized by frequency-specific integration and segregation of the primary somatosensory cortex

We recently proposed that besides levels of local cortical excitability, also distinct pre-stimulus network states (windows to consciousness) determine whether a near-threshold stimulus will be consciously perceived. In the present magnetoencephalography study, we scrutinised these pre-stimulus network states with a focus on the primary somatosensory cortex. For this purpose participants performed a simple near-threshold tactile detection task. Confirming previous studies, we found reduced alpha and beta power in the somatosensory region contralateral to stimulation prior to correct stimulus detection as compared to undetected stimuli, and stronger event-related responses following successful stimulus detection. As expected, using graph theoretical measures, we also observed modulated pre-stimulus network level integration. Specifically, the right primary somatosensory cortex contralateral to stimulation showed an increased integration in the theta band, and additionally, a decreased integration in the beta band. Overall, these results underline the importance of network states for enabling conscious perception. Moreover, they indicate that also a reduction of irrelevant functional connections contributes to the window to consciousness by tuning pre-stimulus pathways of information flow.Julia Natascha Frey, Philipp Ruhnau, Sabine Leske, Markus Siegel, Christoph Braun, Nathan Weis

Systemic functional adaptedness and domain-general cognition: broadening the scope of evolutionary psychology

Evolutionary Psychology tends to be associated with a massively modular cognitive architecture. On this framework of human cognition, an assembly of specialized information processors called modules developed under selection pressures encountered throughout the phylogenic history of hominids. The coordinated activity of domain-specific modules carries out all the processes of belief fixation, abstract reasoning, and other facets of central cognition. Against the massive modularity thesis, I defend an account of systemic functional adaptedness, according to which non-modular systems emerged because of adaptive problems imposed by the intrinsic physiology of the evolving human brain. The proposed reformulation of evolutionary theorizing draws from neural network models and Cummins’ (1975) account of systemic functions to identify selection pressures that gave rise to non-modular, domain-general mechanisms in cognitive architecture

Informativeness of Auditory Stimuli Does Not Affect EEG Signal Diversity

Brain signal diversity constitutes a robust neuronal marker of the global states of consciousness. It has been demonstrated that, in comparison to the resting wakefulness, signal diversity is lower during unconscious states, and higher during psychedelic states. A plausible interpretation of these findings is that the neuronal diversity corresponds to the diversity of subjective conscious experiences. Therefore, in the present study we varied an information rate processed by the subjects and hypothesized that greater information rate will be related to richer and more differentiated phenomenology and, consequently, to greater signal diversity. To test this hypothesis speech recordings (excerpts from an audio-book) were presented to subjects at five different speeds (65, 83, 100, 117, and 135% of the original speed). By increasing or decreasing speed of the recordings we were able to, respectively, increase or decrease the presented information rate. We also included a backward (unintelligible) speech presentation and a resting-state condition (no auditory stimulation). We tested 19 healthy subjects and analyzed the recorded EEG signal (64 channels) in terms of Lempel-Ziv diversity (LZs). We report the following findings. First, our main hypothesis was not confirmed, as Bayes Factor indicates evidence for no effect when comparing LZs among five presentation speeds. Second, we found that LZs during the resting-state was greater than during processing of both meaningful and unintelligible speech. Third, an additional analysis uncovered a gradual decrease of diversity over the time-course of the experiment, which might reflect a decrease in vigilance. We thus speculate that higher signal diversity during the unconstrained resting-state might be due to a greater variety of experiences, involving spontaneous attention switching and mind wandering

Darwinian Domain-Generality: The Role of Evolutionary Psychology in the Modularity Debate

Evolutionary Psychology (EP) tends to be associated with a Massively Modular (MM) cognitive architecture. I argue that EP favors a non-MM cognitive architecture. The main point of dispute is whether central cognition, such as abstract reasoning, exhibits domain-general properties. Partisans of EP argue that domain-specific modules govern central cognition, for it is unclear how the cognitive mind could have evolved domain-generality. In response, I defend a distinction between exogenous and endogenous selection pressures, according to which exogenous pressures tend to select for domain-specificity, whereas the latter, endogenous pressures, select in favor of domain-generality. I draw on models from brain network theory to motivate this distinction, and also to establish that a domain-general, non-MM cognitive architecture is the more parsimonious adaptive solution to endogenous pressures

Effects of oculomotor rehabilitation in children with visual and/or oculomotor dysfunction: a systematic review

A visão é essencial para o desenvolvimento das crianças, facilitando as suas habilidades cognitivas, sociais e motoras, e é importante, em especial, para o seu sucesso escolar. A presente revisão sistemática teve como objetivo estudar os efeitos da reabilitação oculomotora nas funções da visão e dos anexos do olho, e nas sensações associadas aos mesmos. Como objetivo secundário, foram estudados os efeitos da reabilitação oculomotora nas funções mentais de crianças com disfunções oculares. A pesquisa foi realizada nas bases de dados PubMed, Web of Science, Psychology and Behavioral Sciences Collection, Academic Search Complete e Scholar Google. Todos os estudos incluídos foram ensaios clínicos randomizados, cuja qualidade metodológica foi avaliada através da Physiotherapy Evidenced Database (PEDro) Scale. Dos nove estudos incluídos na síntese qualitativa, as amostras diziam respeito a crianças com insuficiência de convergência, ambliopia, Transtorno do Défice de Atenção e Hiperatividade, disfunção oculomotora, baixa habilidade de leitura e/ou hipermetropia. Todos os estudos demonstraram associação positiva entre o programa de reabilitação oculomotora em teste e a melhoria dos parâmetros visuais, oculomotores e/ou mentais, em crianças entre os 5 e os 17 anos de idade. Apesar do número de ameaças que colocam em causa as inferências destes achados, os resultados clínicos gerais sugerem que os programas de reabilitação oculomotora têm efeitos positivos nas funções da visão e dos anexos do olho e sensações associadas, bem como na cognição, comportamento e habilidades de leitura de crianças com disfunção oculomotora. São necessárias investigações adicionais para confirmar a eficácia da terapia oculomotora e para escolher o melhor programa de intervenção para cada paciente, dependendo dos objetivos de intervenção e das suas características clínicas e pessoais.Vision is essential to children development, facilitating cognitive, social and motor skills, and it is important, in particular, for school success. This systematic review aimed to study the effects of oculomotor rehabilitation on the functions of vision and structures adjoining the eye and on sensations associated, in children. As a secondary objective, the effects of oculomotor rehabilitation on the mental functions of children with ocular dysfunctions was studied. The research was conducted in PubMed, Web of Science, Psychology and Behavioral Sciences Collection, Academic Search Complete and Scholar Google databases. All the studies included were randomized controlled trials (RCT), which methodological quality was assessed with The Physiotherapy Evidence Database (PEDro) Scale. From the nine studies included in qualitative synthesis, the samples concerned children with convergence insufficiency, amblyopia, Attention Deficit Hyperactivity Disorder (ADHD), oculomotor dysfunction, poor reading skills, and/or hypermetropia. All of the studies demonstrated a positive association between the oculomotor rehabilitation program under test and improvement on visual, oculomotor and/or mental parameters, in children aged between 5 and 17 years old. Despite the number of threats that challenge the inferences of these findings, the overall clinical results suggest that oculomotor rehabilitation programs have positive effects on the functions of vision and structures adjoining the eye and sensations associated, as well as on cognition, behavior and reading skills of children with oculomotor dysfunction. Additional investigation is required to confirm the efficiency of oculomotor therapy and to choose the best intervention program to each patient, depending on the intervention objectives and their clinical and personal characteristics

Special Patterns of Dynamic Brain Networks Discriminate Between Face and Non-face Processing: A Single-Trial EEG Study

Face processing is a spatiotemporal dynamic process involving widely distributed and closely connected brain regions. Although previous studies have examined the topological differences in brain networks between face and non-face processing, the time-varying patterns at different processing stages have not been fully characterized. In this study, dynamic brain networks were used to explore the mechanism of face processing in human brain. We constructed a set of brain networks based on consecutive short EEG segments recorded during face and non-face (ketch) processing respectively, and analyzed the topological characteristic of these brain networks by graph theory. We found that the topological differences of the backbone of original brain networks (the minimum spanning tree, MST) between face and ketch processing changed dynamically. Specifically, during face processing, the MST was more line-like over alpha band in 0–100 ms time window after stimuli onset, and more star-like over theta and alpha bands in 100–200 and 200–300 ms time windows. The results indicated that the brain network was more efficient for information transfer and exchange during face processing compared with non-face processing. In the MST, the nodes with significant differences of betweenness centrality and degree were mainly located in the left frontal area and ventral visual pathway, which were involved in the face-related regions. In addition, the special MST patterns can discriminate between face and ketch processing by an accuracy of 93.39%. Our results suggested that special MST structures of dynamic brain networks reflected the potential mechanism of face processing in human brain

Systemic functional adaptedness and domain-general cognition: broadening the scope of evolutionary psychology

Evolutionary Psychology tends to be associated with a massively modular cognitive architecture. On this framework of human cognition, an assembly of specialized information processors called modules developed under selection pressures encountered throughout the phylogenic history of hominids. The coordinated activity of domain-specific modules carries out all the processes of belief fixation, abstract reasoning, and other facets of central cognition. Against the massive modularity thesis, I defend an account of systemic functional adaptedness, according to which non-modular systems emerged because of adaptive problems imposed by the intrinsic physiology of the evolving human brain. The proposed reformulation of evolutionary theorizing draws from neural network models and Cummins’ (1975) account of systemic functions to identify selection pressures that gave rise to non-modular, domain-general mechanisms in cognitive architecture