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Ketamine is a dissociative anesthetic that induces a shift in global consciousness states and related brain dynamics. Portable low-density EEG systems could be used to monitor these effects. However, previous evidence is almost null and lacks adequate methods to address global dynamics with a small number of electrodes. This study delves into brain high-order interactions (HOI) to explore the effects of ketamine using portable EEG. In a double-blinded cross-over design, 30 male adults (mean age = 25.57, SD = 3.74) were administered racemic ketamine and compared against saline infusion as a control. Both task-driven (auditory oddball paradigm) and resting-state EEG were recorded. HOI were computed using advanced multivariate information theory tools, allowing us to quantify nonlinear statistical dependencies between all possible electrode combinations. Ketamine induced an increase in redundancy in brain dynamics (copies of the same information that can be retrieved from 3 or more electrodes), most significantly in the alpha frequency band. Redundancy was more evident during resting state, associated with a shift in conscious states towards more dissociative tendencies. Furthermore, in the task-driven context (auditory oddball), the impact of ketamine on redundancy was more significant for predictable (standard stimuli) compared to deviant ones. Finally, associations were observed between ketamine's HOI and experiences of derealization. Ketamine appears to increase redundancy and HOI across psychometric measures, suggesting these effects are correlated with alterations in consciousness towards dissociation. In comparisons with event-related potential (ERP) or standard functional connectivity metrics, HOI represent an innovative method to combine all signal spatial interactions obtained from low-density dry EEG in drug interventions, as it is the only approach that exploits all possible combinations between electrodes. This research emphasizes the potential of complexity measures coupled with portable EEG devices in monitoring shifts in consciousness, especially when paired with low-density configurations, paving the way for better understanding and monitoring of pharmacological-induced changes.
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Encéfalo , Estudios Cruzados , Electroencefalografía , Ketamina , Humanos , Ketamina/farmacología , Masculino , Adulto , Método Doble Ciego , Adulto Joven , Encéfalo/efectos de los fármacos , Encéfalo/fisiología , Anestésicos Disociativos/farmacología , Anestésicos Disociativos/administración & dosificación , Descanso , Estado de Conciencia/efectos de los fármacos , Estado de Conciencia/fisiologíaRESUMEN
In human and nonhuman primates, deep brain stimulation applied at or near the internal medullary lamina of the thalamus [a region referred to as "central thalamus," (CT)], but not at nearby thalamic sites, elicits major changes in the level of consciousness, even in some minimally conscious brain-damaged patients. The mechanisms behind these effects remain mysterious, as the connections of CT had not been specifically mapped in primates. In marmoset monkeys (Callithrix jacchus) of both sexes, we labeled the axons originating from each of the various CT neuronal populations and analyzed their arborization patterns in the cerebral cortex and striatum. We report that, together, these CT populations innervate an array of high-level frontal, posterior parietal, and cingulate cortical areas. Some populations simultaneously target the frontal, parietal, and cingulate cortices, while others predominantly target the dorsal striatum. Our data indicate that CT stimulation can simultaneously engage a heterogeneous set of projection systems that, together, target the key nodes of the attention, executive control, and working-memory networks of the brain. Increased functional connectivity in these networks has been previously described as a signature of consciousness.SIGNIFICANCE STATEMENT In human and nonhuman primates, deep brain stimulation at a specific site near the internal medullary lamina of the thalamus ["central thalamus," (CT)] had been shown to restore arousal and awareness in anesthetized animals, as well as in some brain-damaged patients. The mechanisms behind these effects remain mysterious, as CT connections remain poorly defined in primates. In marmoset monkeys, we mapped with sensitive axon-labeling methods the pathways originated from CT. Our data indicate that stimulation applied in CT can simultaneously engage a heterogeneous set of projection systems that, together, target several key nodes of the attention, executive control, and working-memory networks of the brain. Increased functional connectivity in these networks has been previously described as a signature of consciousness.
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Lesiones Encefálicas , Callithrix , Masculino , Animales , Femenino , Humanos , Tálamo/fisiología , Corteza Cerebral/fisiología , Nivel de Alerta/fisiología , Estado de Conciencia/fisiología , Vías Nerviosas/fisiologíaRESUMEN
Dissipative systems evolve in the preferred temporal direction indicated by the thermodynamic arrow of time. The fundamental nature of this temporal asymmetry led us to hypothesize its presence in the neural activity evoked by conscious perception of the physical world, and thus its covariance with the level of conscious awareness. We implemented a data-driven deep learning framework to decode the temporal inversion of electrocorticography signals acquired from non-human primates. Brain activity time series recorded during conscious wakefulness could be distinguished from their inverted counterparts with high accuracy, both using frequency and phase information. However, classification accuracy was reduced for data acquired during deep sleep and under ketamine-induced anesthesia; moreover, the predictions obtained from multiple independent neural networks were less consistent for sleep and anesthesia than for conscious wakefulness. Finally, the analysis of feature importance scores highlighted transitions between slow ($\approx$20 Hz) and fast frequencies (>40 Hz) as the main contributors to the temporal asymmetry observed during conscious wakefulness. Our results show that a preferred temporal direction is manifest in the neural activity evoked by conscious mentation and in the phenomenology of the passage of time, establishing common ground to tackle the relationship between brain and subjective experience.
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Estado de Conciencia , Ketamina , Animales , Estado de Conciencia/fisiología , Vigilia/fisiología , Electrocorticografía , Sueño/fisiología , Ketamina/farmacología , Encéfalo/fisiologíaRESUMEN
Understanding the neural basis of consciousness is a fundamental goal of neuroscience, and sensory perception is often used as a proxy for consciousness in empirical studies. However, most studies rely on reported perception of visual stimuli. Here we present behavior, high density scalp EEG and eye metric recordings collected simultaneously during a novel tactile threshold perception task. We found significant N80, N140 and P300 event related potentials in perceived trials and in perceived versus not perceived trials. Significance was limited to a P100 and P300 in not perceived trials. We also found an increase in pupil diameter and blink rate and a decrease in microsaccade rate following perceived relative to not perceived tactile stimuli. These findings support the use of eye metrics as a measure of physiological arousal associated with conscious perception. Eye metrics may also represent a novel path toward the creation of tactile no-report tasks in the future.
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Estado de Conciencia , Percepción del Tacto , Estado de Conciencia/fisiología , Electroencefalografía , Humanos , Cuero Cabelludo , Tacto/fisiología , Percepción Visual/fisiologíaRESUMEN
Detection of novel stimuli that violate statistical regularities in the sensory scene is of paramount importance for the survival of biological organisms. Event-related potentials, phasic increases in pupil size, and evoked changes in oscillatory power have been proposed as markers of sensory novelty detection. However, how conscious access to novelty modulates these different brain responses is not well understood. Here, we studied the neural responses to sensory novelty in the auditory modality with and without conscious access. We identified individual thresholds for conscious auditory discrimination and presented to our participants sequences of tones, where the last stimulus could be another standard, a subthreshold target or a suprathreshold target. Participants were instructed to report whether the last tone of each sequence was the same or different from those preceding it. Results indicate that attentional orientation to behaviorally relevant stimuli and overt decision-making mechanisms, indexed by the P3 event-related response and reaction times, best predict whether a novel stimulus will be consciously accessed. Theta power and pupil size do not predict conscious access to novelty, but instead reflect information maintenance and unexpected sensory uncertainty. These results highlight the interplay between bottom-up and top-down mechanisms and how the brain weights neural responses to novelty and uncertainty during perception and goal-directed behavior.
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Estado de Conciencia , Electroencefalografía , Estimulación Acústica , Atención/fisiología , Percepción Auditiva/fisiología , Estado de Conciencia/fisiología , Electroencefalografía/métodos , Potenciales Evocados/fisiología , HumanosRESUMEN
Modern neuroscience addresses the problem of the global functioning of the brain in order to understand the neurobiological processes that underlie mental functions, and especially, consciousness. Brain activity is based on the exchange of information between neurons through contacts or synapses. Neurons form networks of connection between them (circuits), which are dedicated to processing a specific type of information (visual, auditory, motor ...). The circuits establish networks among themselves, combining different modalities of information to generate what we know as mental activity. The study of connections between cortical regions, which has been called connectome, is being approached through neuroimaging techniques such as nuclear magnetic resonance that provide data on the density of connections in the brain. The brain's ability to create new connections based on experience (brain plasticity) suggests that the connectome is a dynamic structure in constant interaction with external and internal stimuli. The question about whether knowledge of an individual's connectome would allow us to predict his or her behavior seems to have no clear answer yet, because we do not know the physical parameters that link the complexity of the brain's connections with the appearance of mental functions and consciousness. At the moment, it seems that the complex and unpredictable behavior is not the simple result of linear processes of neuronal interaction. Uncertainty prevails over determinism, which opens the door to the possibility of a quantum mechanism to explain consciousness.
La neurociencia moderna aborda el problema de funcionamiento global del cerebro para poder comprender los procesos neurobiológicos que subyacen a las funciones mentales, y especialmente, a la consciencia. La actividad cerebral está basada en el intercambio de información entre neuronas a través de contactos llamados sinapsis. Las neuronas forman redes de conexión entre ellas (circuitos), que están dedicados a procesar una parcela específica de información (visual, auditiva, motora ...). Los circuitos establecen redes entre ellos, combinando diferentes modalidades de información para generar lo que conocemos como actividad mental. El estudio de las conexiones entre regiones corticales, que se ha llamado conectoma, está siendo abordado mediante técnicas de neuroimagen como la resonancia magnética nuclear, que aportan datos sobre la densidad de conexiones del cerebro. La capacidad del cerebro de crear nuevas conexiones en función de la experiencia (plasticidad cerebral), sugiere que el conectoma es una estructura dinámica en constante interacción con estímulos externos e internos. La pregunta sobre si el conocimiento del conectoma de un individuo nos permitiría predecir su conducta parece que todavía no tiene respuesta clara, porque no conocemos los parámetros físicos que ligan la complejidad de las conexiones del cerebro con la aparición de las funciones mentales y de la consciencia. Por el momento, parece que la compleja e impredecible conducta no es el simple resultado de procesos lineales de interacción neuronal. La incertidumbre prima al determinismo, lo que abre la puerta a la posibilidad de un mecanismo cuántico para explicar la consciencia.
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Conectoma , Neurociencias , Encéfalo/fisiología , Conectoma/métodos , Estado de Conciencia/fisiología , Femenino , Humanos , Masculino , NeuronasRESUMEN
The Analgesia Nociception Index (ANI), an objective measure of pain based on heart rate variability (HRV), has its usefulness in awake patients still unclear. This systematic review and meta-analysis aimed to assess ANI's accuracy compared to self-reported pain measures in conscious individuals undergoing medical procedures or painful stimuli. PubMed, Ovid, Web of Science, Scopus, Embase, and grey literature were searched until March 2021. Of the 832 identified citations, 16 studies complied with the eligibility criteria. A meta-analysis including nine studies demonstrated a weak negative correlation between ANI and NRS for pain assessment in individuals in the post-anesthetic recovery room (r = - 0.0984, 95% CI = - 0.397 to 0.220, I2 = 95.82%), or in those submitted to electrical stimulus (r = - 0.089; 95% CI = - 0.390 to 0.228, I2 = 0%). The evidence to use ANI in conscious individuals is weak compared to self-report measures of pain, yet ANI explains a part of self-report. Therefore, some individuals may be benefited from the use of ANI during procedures or in the immediate postoperative period.
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Estado de Conciencia/fisiología , Frecuencia Cardíaca/fisiología , Dimensión del Dolor/métodos , Dolor Postoperatorio/diagnóstico , Autoinforme , Vigilia/fisiología , Periodo de Recuperación de la Anestesia , Humanos , Periodo PosoperatorioRESUMEN
To determine the role of early acquisition of blood oxygen level-dependent (BOLD) signals and diffusion tensor imaging (DTI) for analysis of the connectivity of the ascending arousal network (AAN) in predicting neurological outcomes after acute traumatic brain injury (TBI), cardiopulmonary arrest (CPA), or stroke. A prospective analysis of 50 comatose patients was performed during their ICU stay. Image processing was conducted to assess structural and functional connectivity of the AAN. Outcomes were evaluated after 3 and 6 months. Nineteen patients (38%) had stroke, 18 (36%) CPA, and 13 (26%) TBI. Twenty-three patients were comatose (44%), 11 were in a minimally conscious state (20%), and 16 had unresponsive wakefulness syndrome (32%). Univariate analysis demonstrated that measurements of diffusivity, functional connectivity, and numbers of fibers in the gray matter, white matter, whole brain, midbrain reticular formation, and pontis oralis nucleus may serve as predictive biomarkers of outcome depending on the diagnosis. Multivariate analysis demonstrated a correlation of the predicted value and the real outcome for each separate diagnosis and for all the etiologies together. Findings suggest that the above imaging biomarkers may have a predictive role for the outcome of comatose patients after acute TBI, CPA, or stroke.
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Trastornos de la Conciencia , Vías Nerviosas , Adulto , Anciano , Nivel de Alerta , Biomarcadores , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Lesiones Encefálicas/fisiopatología , Lesiones Traumáticas del Encéfalo/complicaciones , Lesiones Traumáticas del Encéfalo/diagnóstico , Coma/diagnóstico por imagen , Coma/etiología , Coma/fisiopatología , Estado de Conciencia/fisiología , Trastornos de la Conciencia/diagnóstico por imagen , Trastornos de la Conciencia/etiología , Trastornos de la Conciencia/fisiopatología , Imagen de Difusión Tensora , Femenino , Paro Cardíaco/complicaciones , Paro Cardíaco/diagnóstico , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Saturación de Oxígeno , Pronóstico , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnósticoRESUMEN
Consciousness transiently fades away during deep sleep, more stably under anesthesia, and sometimes permanently due to brain injury. The development of an index to quantify the level of consciousness across these different states is regarded as a key problem both in basic and clinical neuroscience. We argue that this problem is ill-defined since such an index would not exhaust all the relevant information about a given state of consciousness. While the level of consciousness can be taken to describe the actual brain state, a complete characterization should also include its potential behavior against external perturbations. We developed and analyzed whole-brain computational models to show that the stability of conscious states provides information complementary to their similarity to conscious wakefulness. Our work leads to a novel methodological framework to sort out different brain states by their stability and reversibility, and illustrates its usefulness to dissociate between physiological (sleep), pathological (brain-injured patients), and pharmacologically-induced (anesthesia) loss of consciousness.
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Encéfalo/fisiología , Estado de Conciencia , Encéfalo/diagnóstico por imagen , Biología Computacional , Estado de Conciencia/clasificación , Estado de Conciencia/fisiología , Humanos , Aprendizaje Automático , Imagen por Resonancia Magnética , Sueño/fisiología , Vigilia/clasificación , Vigilia/fisiologíaRESUMEN
Psychedelic drugs, including lysergic acid diethylamide and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain's anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.
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Encéfalo/fisiología , Estado de Conciencia/fisiología , Alucinógenos/farmacología , Dietilamida del Ácido Lisérgico/farmacología , Neuronas/efectos de los fármacos , Neuronas/fisiología , Agonistas del Receptor de Serotonina 5-HT2/farmacología , Encéfalo/efectos de los fármacos , Entropía , Humanos , Modelos Biológicos , Transmisión SinápticaRESUMEN
This review brings to light critical epistemological and theoretical considerations when studying complex emotional states in animals. We discuss anthropomorphic and Umwelt perspectives of nonhuman animals and the ways in which distinct theories of consciousness and neural processing may restrict the potential for the development of knowledge on the topic. Within the same line of argumentation, we consider influences of the debate between monism and dualism and psychology's behaviorism and cognitive theories. Finally, we contrast the affective consciousness, higher-order emotional consciousness, and constructed emotion theories to further our understanding of complex emotional states in animals.
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Estado de Conciencia/fisiología , Emociones/fisiología , Teoría Psicológica , AnimalesRESUMEN
Recent evidence on resting-state functional magnetic resonance imaging (rs-fMRI) suggests that healthy human brains have a temporal organization represented in a widely complex time-delay structure. This structure seems to underlie brain communication flow, integration/propagation of brain activity, as well as information processing. Therefore, it is probably linked to the emergence of highly coordinated complex brain phenomena, such as consciousness. Nevertheless, possible changes in this structure during an altered state of consciousness remain poorly investigated. In this work, we hypothesized that due to a disruption in high-order functions and alterations of the brain communication flow, patients with disorders of consciousness (DOC) might exhibit changes in their time-delay structure of spontaneous brain activity. We explored this hypothesis by comparing the time-delay projections from fMRI resting-state data acquired in resting state from 48 patients with DOC and 27 healthy controls (HC) subjects. Results suggest that time-delay structure modifies for patients with DOC conditions when compared with HC. Specifically, the average value and the directionality of latency inside the midcingulate cortex (mCC) shift with the level of consciousness. In particular, positive values of latency inside the mCC relate to preserved states of consciousness, whereas negative values change proportionally with the level of consciousness in patients with DOC. These results suggest that the mCC may play a critical role as an integrator of brain activity in HC subjects, but this role vanishes in an altered state of consciousness.
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Encéfalo/diagnóstico por imagen , Trastornos de la Conciencia/diagnóstico por imagen , Estado de Conciencia/fisiología , Imagen por Resonancia Magnética/métodos , Oxígeno/sangre , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/fisiopatología , Trastornos de la Conciencia/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Descanso , Índice de Severidad de la Enfermedad , Factores de Tiempo , Adulto JovenRESUMEN
INTRODUCTION: Functional connectivity alterations within individual resting state networks (RSNs) are linked to disorders of consciousness (DOC). If these alterations influence the interaction quality with other RNSs, then, brain alterations in patients with DOC would be characterized by connectivity changes in the large-scale model composed of RSNs. How are functional interactions between RSNs influenced by internal alterations of individual RSNs? Do the functional alterations induced by DOC change some key properties of the large-scale network, which have been suggested to be critical for the consciousness emergence? Here, we use network analysis to measure functional connectivity in patients with DOC and address these questions. We hypothesized that network properties provide descriptions of brain functional reconfiguration associated with consciousness alterations. METHODS: We apply nodal and global network measurements to study the reconfiguration linked with the disease severity. We study changes in integration, segregation, and centrality properties of the functional connectivity between the RSNs in subjects with different levels of consciousness. RESULTS: Our analysis indicates that nodal measurements are more sensitive to disease severity than global measurements, particularly, for functional connectivity of sensory and cognitively related RSNs. CONCLUSION: The network property alterations of functional connectivity in different consciousness levels suggest a whole-brain topological reorganization of the large-scale functional connectivity in patients with DOC.
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Encéfalo/fisiopatología , Trastornos de la Conciencia/fisiopatología , Red Nerviosa/fisiopatología , Adulto , Anciano , Encéfalo/diagnóstico por imagen , Estado de Conciencia/fisiología , Trastornos de la Conciencia/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Modelos Neurológicos , Red Nerviosa/diagnóstico por imagenRESUMEN
Interest in the causal relation between consciousness and the underlying neuronal activity has grown in recent decades. Numerous experimental studies have been carried out on the brain structures and networks underlying consciousness in animal models, in patients with brain damage and with very precise functional neuroimaging. In spite of the great multitude of findings, there is no theoretical proposal that integrates this knowledge under a coherent theoretical framework based on the evidence obtained. Existing theories offer a dismembered view of consciousness, since they pose causal explanations that do not include a global functional perspective of the interaction of the different brain networks involved in consciousness. This work offers a theoretical framework that integrates the empirical knowledge, generated in recent decades, into a neurofunctional model of consciousness. This model represents consciousness as an epiphenomenon resulting from the sequential activation of different neural loops that are formed by specific brain structures and networks which receive feedback from their own operations in order to reconfigure their own functional states and the entire system. The ascending reticular activating system, the thalamocortical networks and the cortico-cortical networks sustain cognitive processes that are differentiated, although highly dependent and fundamental for the final experience of consciousness. All these systems form a single physiological space where the individual can deploy different cognitive skills that allow the emergence of complex behaviours such as language, thought and social cognition.
TITLE: Modelo neurofuncional de la conciencia: bases neurofisiologicas y cognitivas.El interes por la relacion causal existente entre la conciencia y la actividad neuronal subyacente ha aumentado en las ultimas decadas. Se han llevado a cabo numerosos estudios experimentales en modelos animales, en pacientes con daño cerebral y con neuroimagen funcional con una excelente precision sobre las estructuras y redes cerebrales que subyacen a la conciencia. A pesar de la gran multitud de hallazgos, no existe una propuesta teorica que integre este conocimiento bajo un marco teorico coherente basado en las evidencias obtenidas. Las teorias existentes ofrecen una vision desmembrada de la conciencia, ya que plantean explicaciones causales que no incluyen una perspectiva funcional global sobre la interaccion del conjunto de redes cerebrales involucradas en la conciencia. Este trabajo ofrece un marco teorico que integra el conocimiento empirico, generado en las ultimas decadas, en un modelo neurofuncional de la conciencia. Este modelo representa la conciencia como un epifenomeno resultante de la activacion secuencial de diferentes bucles neuronales que estan formados por estructuras y redes cerebrales especificas retroalimentadas por sus propias operaciones para poder reconfigurar sus propios estados funcionales y todo el sistema. El sistema reticular activador ascendente, las redes talamocorticales y las redes corticocorticales sostienen procesos cognitivos diferenciados, aunque altamente dependientes y basicos para la experiencia final de conciencia. Todos estos sistemas forman un unico espacio fisiologico en donde el individuo puede desplegar diferentes habilidades cognitivas que permiten la emergencia de conductas complejas como el lenguaje, el pensamiento y la cognicion social.
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Estado de Conciencia/fisiología , Modelos Neurológicos , Modelos Psicológicos , Corteza Cerebral/fisiología , Emociones/fisiología , Retroalimentación Fisiológica , Actividad Nerviosa Superior/fisiología , Humanos , Memoria/fisiología , Vías Nerviosas/fisiología , Psicofisiología , Tálamo/fisiologíaRESUMEN
BACKGROUND: The Perturbational Complexity Index (PCI) was recently introduced to assess the capacity of thalamocortical circuits to engage in complex patterns of causal interactions. While showing high accuracy in detecting consciousness in brain-injured patients, PCI depends on elaborate experimental setups and offline processing, and has restricted applicability to other types of brain signals beyond transcranial magnetic stimulation and high-density EEG (TMS/hd-EEG) recordings. OBJECTIVE: We aim to address these limitations by introducing PCIST, a fast method for estimating perturbational complexity of any given brain response signal. METHODS: PCIST is based on dimensionality reduction and state transitions (ST) quantification of evoked potentials. The index was validated on a large dataset of TMS/hd-EEG recordings obtained from 108 healthy subjects and 108 brain-injured patients, and tested on sparse intracranial recordings (SEEG) of 9 patients undergoing intracranial single-pulse electrical stimulation (SPES) during wakefulness and sleep. RESULTS: When calculated on TMS/hd-EEG potentials, PCIST performed with the same accuracy as the original PCI, while improving on the previous method by being computed in less than a second and requiring a simpler set-up. In SPES/SEEG signals, the index was able to quantify a systematic reduction of intracranial complexity during sleep, confirming the occurrence of state-dependent changes in the effective connectivity of thalamocortical circuits, as originally assessed through TMS/hd-EEG. CONCLUSIONS: PCIST represents a fundamental advancement towards the implementation of a reliable and fast clinical tool for the bedside assessment of consciousness as well as a general measure to explore the neuronal mechanisms of loss/recovery of brain complexity across scales and models.
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Encéfalo/fisiología , Estado de Conciencia/fisiología , Electroencefalografía/métodos , Investigación Empírica , Estimulación Magnética Transcraneal/métodos , Adulto , Femenino , Humanos , Masculino , Sueño/fisiología , Factores de Tiempo , Vigilia/fisiologíaRESUMEN
INTRODUCTION: According to the High-order Theory of Emotional Consciousness (HOTEC), every emotional process is a conscious and high-order state of mind carried out by the General Networks of Cognition (GNC), which consists mainly of prefrontal mechanisms. This means that anxiety is also an emotional state of mind carried out by the GNC (positive correlation). However, numerous studies have suggested what is commonly called "hypofrontality" during states of anxiety (negative correlation), which seems to give rise to a theoretical and empirical contraction. METHODS: I present a theoretical review to address the following issue: how to advocate a HOTEC view of anxiety in the face of a growing paradigm of hypofrontality during states of anxiety? RESULTS: Here I propose that dmPFC, the dACC, and the anterior insula are GNC areas positively correlated with anxiety, which, along with the prefrontal areas responsible for regulating the activation of survival circuits and driving the attention to adaptive ways to overcome potential threats, form an interconnective model of anticipatory and regulatory mechanisms related to learned threats based on autobiographical memories. CONCLUSIONS: Through this model, I propose that HOTEC is still a valid way to approach and understand both healthy and unhealthy anxious states of mind.
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Ansiedad/diagnóstico por imagen , Estado de Conciencia/fisiología , Emociones/fisiología , Corteza Prefrontal/diagnóstico por imagen , Adulto , Ansiedad/fisiopatología , Atención/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Corteza Prefrontal/fisiopatologíaRESUMEN
Objective: The mind-brain problem (MBP) has marked implications for psychiatry, but has been poorly discussed in the psychiatric literature. This paper evaluates the presentation of the MBP in the three leading general psychiatry journals during the last 20 years. Methods: Systematic review of articles on the MBP published in the three general psychiatry journals with the highest impact factor from 1995 to 2015. The content of these articles was analyzed and discussed in the light of contemporary debates on the MBP. Results: Twenty-three papers, usually written by prestigious authors, explicitly discussed the MBP and received many citations (mean = 130). The two main categories were critiques of dualism and defenses of physicalism (mind as a brain product). These papers revealed several misrepresentations of theoretical positions and lacked relevant contemporary literature. Without further discussion or evidence, they presented the MBP as solved, dualism as an old-fashioned or superstitious idea, and physicalism as the only rational and empirically confirmed option. Conclusion: The MBP has not been properly presented and discussed in the three leading psychiatric journals in the last 20 years. The few articles on the topic have been highly cited, but reveal misrepresentations and lack of careful philosophical discussion, as well as a strong bias against dualism and toward a materialist/physicalist approach to psychiatry.
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Humanos , Psiquiatría/estadística & datos numéricos , Psicofisiología , Publicaciones/estadística & datos numéricos , Encéfalo/fisiología , Neurociencias , Estado de Conciencia/fisiología , Factor de Impacto de la RevistaRESUMEN
Desde la etapa neonatal, la detección temprana de marcadores conductuales de alteraciones sutiles en el neurodesarrollo, es un campo todavía en crecimiento. El objetivo de esta revisión es describir los mecanismos que subyacen a la conducta del neonato durante la aplicación de la subescala de habituación que forma parte de la Neonatal Behavioral Assessment Scale (NBAS), con especial énfasis en la vía visual. Se destacan el papel de la habituación y la regulación de los estados de conciencia como los mecanismos fundamentales durante el primer estímulo y del segundo al décimo estímulo, en dicha escala. Estos procesos representan una capacidad fundamental para la adaptación del recién nacido y se discuten sus posibles implicaciones en el desempeño cognitivo posterior.
Since the neonatal stage, early detection of behavioral markers of subtle impairments in neurodevelopment is a field still under growth. The objective of this review is to describe the mechanisms underlying neonatal behavior during the habituation scale of NBAS, that emphasizes the visual pathway. The role of habituation and the regulation of behavioral states are highlighted during the first stimuli and the second to ten stimuli, during performance of NBAS. Those processes represent a fundamental capacity for newborns´ adaptation and are discussed in line to later cognitive performance.
Asunto(s)
Humanos , Animales , Recién Nacido , Desarrollo Infantil/fisiología , Estado de Conciencia/fisiología , Técnicas de Observación Conductual , Habituación PsicofisiológicaRESUMEN
The current study investigated the effect of conscious intention to act on the Bereitschaftspotential. Situations in which the awareness of acting is minimally expressed were generated by asking 16 participants to press a button after performing a mental imagery task based on animal pictures (automatic condition). The affective responses induced by the pictures were controlled by selecting the animals according to different valences, threatening and neutral. The Bereitschaftspotential associated with the button presses was compared to the observed when similar movements were performed under the basic instructions of the self-paced movement paradigm (willed condition). Enhanced Bereitschaftspotential amplitudes were observed in the willed condition with respect to the automatic condition. This effect was manifested as a negative slope at medial frontocentral sites during the last 500 ms before movement onset. The valence of the pictures did not affect the motor preparatory potentials. The results suggest that significant part of the NS' subcomponent of the readiness potential is associated with the attention to-and, presumably, awareness of-intention to move, possibly reflecting cortical activation from supplementary motor areas. Secondarily, our findings supports that the feeling of threat does not influence the Bereitschaftspotential associated with automatic movements. Regarding methodological issues, the behavioural model of spontaneous voluntary movements proposed in automatic condition can benefit investigations on purely motor (or non-cognitive) subcomponents of the Bereitschaftspotential.
Asunto(s)
Atención/fisiología , Concienciación/fisiología , Corteza Cerebral/fisiología , Estado de Conciencia/fisiología , Variación Contingente Negativa/fisiología , Intención , Actividad Motora/fisiología , Reconocimiento Visual de Modelos/fisiología , Volición/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
OBJECTIVE: The mind-brain problem (MBP) has marked implications for psychiatry, but has been poorly discussed in the psychiatric literature. This paper evaluates the presentation of the MBP in the three leading general psychiatry journals during the last 20 years. METHODS: Systematic review of articles on the MBP published in the three general psychiatry journals with the highest impact factor from 1995 to 2015. The content of these articles was analyzed and discussed in the light of contemporary debates on the MBP. RESULTS: Twenty-three papers, usually written by prestigious authors, explicitly discussed the MBP and received many citations (mean = 130). The two main categories were critiques of dualism and defenses of physicalism (mind as a brain product). These papers revealed several misrepresentations of theoretical positions and lacked relevant contemporary literature. Without further discussion or evidence, they presented the MBP as solved, dualism as an old-fashioned or superstitious idea, and physicalism as the only rational and empirically confirmed option. CONCLUSION: The MBP has not been properly presented and discussed in the three leading psychiatric journals in the last 20 years. The few articles on the topic have been highly cited, but reveal misrepresentations and lack of careful philosophical discussion, as well as a strong bias against dualism and toward a materialist/physicalist approach to psychiatry.