Convergence of biological and psychological perspectives on cognitive coordination in schizophrenia

The concept of locally specialized functions dominates research on higher brain function and its disorders. Locally specialized functions must be complemented by processes that coordinate those functions, however, and impairment of coordinating processes may be central to some psychotic conditions. Evidence for processes that coordinate activity is provided by neurobiological and psychological studies of contextual disambiguation and dynamic grouping. Mechanisms by which this important class of cognitive functions could be achieved include those long-range connections within and between cortical regions that activate synaptic channels via NMDA-receptors, and which control gain through their voltage-dependent mode of operation. An impairment of these mechanisms is central to PCP-psychosis, and the cognitive capabilities that they could provide are impaired in some forms of schizophrenia. We conclude that impaired cognitive coordination due to reduced ion flow through NMDA-channels is involved in schizophrenia, and we suggest that it may also be involved in other disorders. This perspective suggests several ways in which further research could enhance our understanding of cognitive coordination, its neural basis, and its relevance to psychopathology

The coherent organization of mental life depends on mechanisms for context-sensitive gain-control that are impaired in schizophrenia

There is rapidly growing evidence that schizophrenia involves changes in context-sensitive gain-control and probabilistic inference. In addition to the well-known cognitive disorganization to which these changes lead, basic aspects of vision are also impaired, as discussed by other papers on this Frontiers Research Topic. The aim of this paper is to contribute to our understanding of such findings by examining five central hypotheses. First, context-sensitive gain-control is fundamental to brain function and mental life. Second, it occurs in many different regions of the cerebral cortex of many different mammalian species. Third, it has several computational functions, each with wide generality. Fourth, it is implemented by several neural mechanisms at cellular and circuit levels. Fifth, impairments of context-sensitive gain-control produce many of the well-known symptoms of schizophrenia and change basic processes of visual perception. These hypotheses suggest why disorders of vision in schizophrenia may provide insights into the nature and mechanisms of impaired reality testing and thought disorder in psychosis. They may also cast light on normal mental function and its neural bases. Limitations of these hypotheses, and ways in which they need further testing and development, are outlined

Réhabilitation cognitive de la schizophrénie : une approche pragmatique du processus d’intégration pour lutter contre les symptômes réfractaires

Les approches classiques de traitement des personnes présentant une schizophrénie s’accordent pour reconnaître que réussir à soigner cette condition requiert davantage qu’une simple réduction de fréquence, d’intensité et de durée des symptômes positifs tels que des hallucinations. En fait, une approche plus complète, dont le but est de réduire l’incapacité s’avère indiquée dans la plupart des cas (Silverstein et al., 2000). Il a été récemment proposé que les nouvelles approches en réhabilitation cognitive de la schizophrénie requièrent la reconnaissance de l’importance de 1) systématiquement aborder la motivation, l’estime de soi, et les facteurs affectifs au moment de concevoir des interventions qui augmentent la cognition ; 2) la nécessité d’aller au-delà des interventions « à taille unique » et de développer des traitements spécifiques à l’individu ; 3) la nécessité d’aborder les anomalies de l’expérience du soi lors de la conception même des interventions d’optimisation des accomplissements cognitifs et comportementaux. L’étude de cas présentée ci-dessous est un exemple d’une approche de la réhabilitation cognitive de la schizophrénie qui tente de promouvoir le processus d’intégration de soi par le recours à une gamme d’interventions spécifiques, en relation avec les trois caractéristiques notées plus haut. Les résultats préliminaires suggèrent que cette approche pourrait être grandement profitable aux patients souffrant de schizophrénie.Classical approaches of treatment of people with schizophrenia recognize that successful treatment of this illness requires more than simply reducing the frequency, intensity and duration of positive symptoms such as hallucinations. In fact, a more comprehensive approach aimed at reducing disability is indicated in most cases (Silverstein et al., 2000). It has recently been proposed that new approaches to the cognitive rehabilitation of schizophrenia need to recognize the importance of 1) systematically addressing motivation, self-esteem, and affective factors when designing cognition enhancing interventions ; 2) the need to move beyond one-size-fits-all interventions and develop individual-specific treatments ; and 3) the need to address abnormalities in the experience of the self when designing interventions to optimize cognitive and behavioural performance. The case study presented here is an example of a cognitive rehabilitation approach of schizophrenia that attempts to promote the self integration process by means of a range of specific interventions and addresses three issues noted above. Preliminary results suggest that it could be very beneficial for patients suffering of schizophrenia.Los enfoques clásicos de tratamiento de las personas que presentan esquizofrenia reconocen que tener éxito en sanar esta condición requiere más que una simple reducción de la frecuencia, intensidad y duración de los síntomas positivos como las alucinaciones. De hecho, un enfoque más completo, cuyo objetivo es reducir la incapacidad, se revela como indicado en la mayoría de los casos (Silverstein et al., 2000). Recientemente se ha propuesto que los nuevos enfoques en la rehabilitación cognitiva de la esquizofrenia requieren reconocer la importancia de 1) abordar sistemáticamente la motivación, la estima de sí mismo y los factores afectivos en el momento de concebir las intervenciones que aumentan la cognición; 2) la necesidad de ir más allá de las intervenciones “de talla única” y de desarrollar los tratamientos específicos para el individuo; 3) la necesidad de abordar las anomalías de la experiencia de sí mismo, en el momento de la concepción misma de las intervenciones de optimización de los logros cognitivos y comportamentales. El estudio de caso presentado a continuación es un ejemplo de un enfoque de rehabilitación cognitiva de la esquizofrenia, que intenta promover el proceso de integración de sí mismo por medio de una gama de intervenciones específicas, en relación con las tres características arriba señaladas. Los resultados preliminares sugieren que este enfoque podría ser de gran provecho para los pacientes que sufren de esquizofrenia.As abordagens clássicas de tratamento das pessoas que apresentam uma esquizofrenia reconhecem que conseguir curar este estado requer mais do que uma simples redução de freqüência, de intensidade e de duração dos sintomas positivos, como as alucinações. De fato, uma abordagem mais completa, cujo objetivo é reduzir a incapacidade, é indicada na maioria dos casos (Silverstein et al., 2000). Foi proposto, recentemente, que as novas abordagens em reabilitação cognitiva da esquizofrenia requeiram o reconhecimento da importância 1) de abordar sistematicamente a motivação, a estima de si e os fatores afetivos no momento de conceber intervenções que aumentem a cognição; 2) da necessidade de ir além das intervenções “de tamanho único” e de desenvolver tratamentos personalizados; 3) da necessidade de abordar as anomalias da experiência do “eu”, na concepção mesmo das intervenções de otimização das realizações cognitivas e comportamentais. O estudo de caso apresentado abaixo é um exemplo de uma abordagem da reabilitação cognitiva da esquizofrenia, que tenta promover o processo de integração de si pelo recurso a uma gama de intervenções específicas, em relação às três características anotadas acima. Os resultados preliminares sugerem que esta abordagem poderia ser muito benéfica para os pacientes que sofrem de esquizofrenia

On the functions, mechanisms, and malfunctions of intracortical contextual modulation

A broad neuron-centric conception of contextual modulation is reviewed and re-assessed in the light of recent neurobiological studies of amplification, suppression, and synchronization. Behavioural and computational studies of perceptual and higher cognitive functions that depend on these processes are outlined, and evidence that those functions and their neuronal mechanisms are impaired in schizophrenia is summarized. Finally, we compare and assess the long-term biological functions of contextual modulation at the level of computational theory as formalized by the theories of coherent infomax and free energy reduction. We conclude that those theories, together with the many empirical findings reviewed, show how contextual modulation at the neuronal level enables the cortex to flexibly adapt the use of its knowledge to current circumstances by amplifying and grouping relevant activities and by suppressing irrelevant activities

Implications of Information Theory for Computational Modeling of Schizophrenia

Information theory provides a formal framework within which information processing and its disorders can be described. However, information theory has rarely been applied to modeling aspects of the cognitive neuroscience of schizophrenia. The goal of this article is to highlight the benefits of an approach based on information theory, including its recent extensions, for understanding several disrupted neural goal functions as well as related cognitive and symptomatic phenomena in schizophrenia. We begin by demonstrating that foundational concepts from information theory—such as Shannon information, entropy, data compression, block coding, and strategies to increase the signal-to-noise ratio—can be used to provide novel understandings of cognitive impairments in schizophrenia and metrics to evaluate their integrity. We then describe more recent developments in information theory, including the concepts of infomax, coherent infomax, and coding with synergy, to demonstrate how these can be used to develop computational models of schizophrenia-related failures in the tuning of sensory neurons, gain control, perceptual organization, thought organization, selective attention, context processing, predictive coding, and cognitive control. Throughout, we demonstrate how disordered mechanisms may explain both perceptual/cognitive changes and symptom emergence in schizophrenia. Finally, we demonstrate that there is consistency between some information-theoretic concepts and recent discoveries in neurobiology, especially involving the existence of distinct sites for the accumulation of driving input and contextual information prior to their interaction. This convergence can be used to guide future theory, experiment, and treatment development

Traitement multimodal de l’agressivité et de la violence chez des personnes souffrant de psychose

Dans cet article, les auteurs décrivent les traitements non pharmacologiques qui ont fait preuve d’efficacité pour réduire l’agressivité et la violence chez les personnes souffrant de psychose. Ils présentent ensuite une approche de formulation/planification du traitement qui aborde les influences étiologiques complexes, et les facteurs multiples qui jouent sur le maintien du comportement agressif chez ces patients. Finalement, ils présentent en exemple un cas où l’on se sert de cette approche.In this article, the authors offer a description of nonpharmacological treatments which have demonstrated effectiveness in reducing aggression and violence in patient with psychosis ; present a case formulation/treatment planning approach which addresses the complex etiological influences and multiple factors affecting maintenance of aggressive behavior in PI ; finally, they provide a case example of this approach.En este artículo, los autores describen los tratamientos no farmacológicos que han demostrado ser eficaces en la reducción de la agresividad y la violencia en las personas que sufren de psicosis. Enseguida, presentan un enfoque de formulación/planificación del tratamiento que aborda las influencias etiológicas complejas y los múltiples factores que tienen un efecto en el mantenimiento del comportamiento agresivo en estos pacientes. Finalmente, presentan como ejemplo un caso en el que se sirven de este enfoque.Neste artigo, os autores descrevem os tratamentos não farmacológicos que provaram ser eficazes para reduzir a agressividade e a violência nas pessoas que sofrem de psicose. Eles apresentam em seguida uma abordagem de formulação/planificação do tratamento que aborda as influências etimológicas complexas, e os fatores múltiplos que influenciam sobre a manutenção do comportamento agressivo nestes pacientes. Finalmente, eles apresentam o exemplo de um caso onde esta abordagem foi utilizada

Techniques interpersonnelles pour optimiser les résultats positifs de la réhabilitation psychiatrique (deuxième partie)

Il existe maintenant un certain nombre de traitements comportementaux basés sur le milieu ou le groupe qui ont démontré leur efficacité auprès des patients souffrant de schizophrénie dits « réfractaires aux traitements » Toutefois, il est peu probable que ces interventions atteignent leur impact maximal, à moins que le personnel soignant ne s’inspire systématiquement des principes comportementaux dans leurs interactions constantes avec les patients tout au cours de la journée. Dans cet article, les auteurs décrivent certaines techniques interpersonnelles qui sont efficaces pour la gestion d’une gamme variée de comportements institutionnalisés/dépendants et provocateurs/agressifs. Chaque technique est expliquée et des exemples détaillés sont présentés, afin d’illustrer des réponses appropriées et inappropriées de la part du personnel soignant à l’égard des comportements des patients. La discussion conclut avec une description d’un contrat de comportement réussi qui s’inspire de certaines de ces techniques.There now exist a number of milieu-based and group-based behavioral treatments that have demonstrated effectiveness with so-called “treatment-refractory” schizophrenia patients. These interventions are not likely to achieve their maximal impact, however, unless program staff consistently employ behavioral principles in their moment-to-moment interactions with patients throughout the day. In this paper we describe a number of interpersonal techniques that are effective in dealing with a variety of institutionalized/dependent and provocative/aggressive behaviors. Each technique is explained and detailed examples are given to demonstrate appropriate and inappropriate staff responses to patient behavior. The discussion ends with the description of a successful behavior contract that employed a number of these techniques.Actualmente existe un cierto número de tratamientos comportamentales, basados en el medio o el grupo, que han demostrado su eficacia en los pacientes esquizofrénicos llamados “refractarios a los tratamientos”. Sin embargo, es poco probable que estas intervenciones alcancen su impacto máximo, a menos de que el personal de asistencia médica se inspire sistemáticamente de los principios comportamentales en sus interacciones constantes con los pacientes a lo largo de todo el día. En este artículo, los autores describen ciertas técnicas interpersonales que son eficaces para la gestión de una gama variada de comportamientos institucionalizados/dependientes y provocadores/ agresivos. Se explica cada técnica y se presentan ejemplos detallados a fin de ilustrar las respuestas apropiadas e inapropiadas del personal de asistencia médica con respecto a los comportamientos de los pacientes. La discusión concluye con la descripción de un acuerdo de comportamiento exitoso que se inspira de algunas de estas técnicas.Existem atualmente alguns tratamentos comportamentais baseados no meio ou no grupo, que demonstraram sua eficácia junto a pacientes que sofrem de esquizofrenia ditos “refratários aos tratamentos”. Entretanto, é pouco provável que estas intervenções atinjam seu impacto máximo, a menos que os funcionários que tratam destes pacientes inspirem-se sistematicamente dos princípios comportamentais em suas interações constantes com os pacientes durante o dia. Neste artigo, os autores descrevem algumas técnicas impessoais que são eficazes para a gestão de uma vasta gama de comportamentos institucionalizados/dependentes e provocadores/agressivos. Cada técnica é explicada e exemplos detalhados estão presentes para ilustrar respostas apropriadas e não apropriadas da parte dos funcionários que tratam destes pacientes no que diz respeito aos comportamentos destes. A discussão conclui com a descrição de um contrato de comportamento que deu certo que inspira-se de algumas destas técnicas

The effects of arousal on apical amplification and conscious state

Neocortical pyramidal cells can integrate two classes of input separately and use one to modulate response to the other. Their tuft dendrites are electrotonically separated from basal dendrites and soma by the apical dendrite, and apical hyperpolarization-activated currents (Ih) further isolate subthreshold integration of tuft inputs. When apical depolarization exceeds a threshold, however, it can enhance response to the basal inputs that specify the cell’s selective sensitivity. This process is referred to as apical amplification (AA). We review evidence suggesting that, by regulating Ihin the apical compartments, adrenergic arousal controls the coupling between apical and somatic integration zones thus modifying cognitive capabilities closely associated with consciousness. Evidence relating AA to schizophrenia, sleep, and anesthesia is reviewed, and we assess theories that emphasize the relevance of AA to consciousness. Implications for theories of neocortical computation that emphasize context-sensitive modulation are summarized. We conclude that the findings concerning AA and its regulation by arousal offer a new perspective on states of consciousness, the function and evolution of neocortex, and psychopathology. Many issues worthy of closer examination arise

Functional network changes and cognitive control in schizophrenia

Cognitive control is a cognitive and neural mechanism that contributes to managing the complex demands of day-to-day life. Studies have suggested that functional impairments in cognitive control associated brain circuitry contribute to a broad range of higher cognitive deficits in schizophrenia. To examine this issue, we assessed functional connectivity networks in healthy adults and individuals with schizophrenia performing tasks from two distinct cognitive domains that varied in demands for cognitive control, the RiSE episodic memory task and DPX goal maintenance task. We characterized general and cognitive control-specific effects of schizophrenia on functional connectivity within an expanded frontal parietal network (FPN) and quantified network topology properties using graph analysis. Using the network based statistic (NBS), we observed greater network functional connectivity in cognitive control demanding conditions during both tasks in both groups in the FPN, and demonstrated cognitive control FPN specificity against a task independent auditory network. NBS analyses also revealed widespread connectivity deficits in schizophrenia patients across all tasks. Furthermore, quantitative changes in network topology associated with diagnostic status and task demand were observed. The present findings, in an analysis that was limited to correct trials only, ensuring that subjects are on task, provide critical insights into network connections crucial for cognitive control and the manner in which brain networks reorganize to support such control. Impairments in this mechanism are present in schizophrenia and these results highlight how cognitive control deficits contribute to the pathophysiology of this illness