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Trends in Cognitive Sciences Oct 2020How does consciousness vary across the animal kingdom? Are some animals 'more conscious' than others? This article presents a multidimensional framework for... (Review)
Review
How does consciousness vary across the animal kingdom? Are some animals 'more conscious' than others? This article presents a multidimensional framework for understanding interspecies variation in states of consciousness. The framework distinguishes five key dimensions of variation: perceptual richness, evaluative richness, integration at a time, integration across time, and self-consciousness. For each dimension, existing experiments that bear on it are reviewed and future experiments are suggested. By assessing a given species against each dimension, we can construct a consciousness profile for that species. On this framework, there is no single scale along which species can be ranked as more or less conscious. Rather, each species has its own distinctive consciousness profile.
Topics: Animals; Consciousness
PubMed: 32830051
DOI: 10.1016/j.tics.2020.07.007 -
Cold Spring Harbor Perspectives in... Mar 2015The idea that memory is not a single mental faculty has a long and interesting history but became a topic of experimental and biologic inquiry only in the mid-20th... (Review)
Review
The idea that memory is not a single mental faculty has a long and interesting history but became a topic of experimental and biologic inquiry only in the mid-20th century. It is now clear that there are different kinds of memory, which are supported by different brain systems. One major distinction can be drawn between working memory and long-term memory. Long-term memory can be separated into declarative (explicit) memory and a collection of nondeclarative (implicit) forms of memory that include habits, skills, priming, and simple forms of conditioning. These memory systems depend variously on the hippocampus and related structures in the parahippocampal gyrus, as well as on the amygdala, the striatum, cerebellum, and the neocortex. This work recounts the discovery of declarative and nondeclarative memory and then describes the nature of declarative memory, working memory, nondeclarative memory, and the relationship between memory systems.
Topics: Brain; Consciousness; Humans; Memory, Long-Term; Memory, Short-Term; Models, Neurological; Unconscious, Psychology
PubMed: 25731765
DOI: 10.1101/cshperspect.a021667 -
Journal of Integrative Neuroscience Mar 2021This article describes neural models of attention. Since attention is not a disembodied process, the article explains how brain processes of consciousness, learning,... (Review)
Review
This article describes neural models of attention. Since attention is not a disembodied process, the article explains how brain processes of consciousness, learning, expectation, attention, resonance, and synchrony interact. These processes show how attention plays a critical role in dynamically stabilizing perceptual and cognitive learning throughout our lives. Classical concepts of object and spatial attention are replaced by mechanistically precise processes of prototype, boundary, and surface attention. Adaptive resonances trigger learning of bottom-up recognition categories and top-down expectations that help to classify our experiences, and focus prototype attention upon the patterns of critical features that predict behavioral success. These feature-category resonances also maintain the stability of these learned memories. Different types of resonances induce functionally distinct conscious experiences during seeing, hearing, feeling, and knowing that are described and explained, along with their different attentional and anatomical correlates within different parts of the cerebral cortex. All parts of the cerebral cortex are organized into layered circuits. Laminar computing models show how attention is embodied within a canonical laminar neocortical circuit design that integrates bottom-up filtering, horizontal grouping, and top-down attentive matching. Spatial and motor processes obey matching and learning laws that are computationally complementary to those obeyed by perceptual and cognitive processes. Their laws adapt to bodily changes throughout life, and do not support attention or conscious states.
Topics: Attention; Brain; Cognition; Consciousness; Humans; Learning; Models, Theoretical
PubMed: 33834707
DOI: 10.31083/j.jin.2021.01.406 -
Neuron Mar 2020We review the central tenets and neuroanatomical basis of the global neuronal workspace (GNW) hypothesis, which attempts to account for the main scientific observations... (Review)
Review
We review the central tenets and neuroanatomical basis of the global neuronal workspace (GNW) hypothesis, which attempts to account for the main scientific observations regarding the elementary mechanisms of conscious processing in the human brain. The GNW hypothesis proposes that, in the conscious state, a non-linear network ignition associated with recurrent processing amplifies and sustains a neural representation, allowing the corresponding information to be globally accessed by local processors. We examine this hypothesis in light of recent data that contrast brain activity evoked by either conscious or non-conscious contents, as well as during conscious or non-conscious states, particularly general anesthesia. We also discuss the relationship between the intertwined concepts of conscious processing, attention, and working memory.
Topics: Anesthesia, General; Attention; Brain; Cognition; Consciousness; Humans; Memory, Short-Term; Neurons; Psychological Theory
PubMed: 32135090
DOI: 10.1016/j.neuron.2020.01.026 -
Neurosurgical Focus Aug 2018Traumatic brain injury (TBI) is a looming epidemic, growing most rapidly in the elderly population. Some of the most devastating sequelae of TBI are related to depressed... (Review)
Review
Traumatic brain injury (TBI) is a looming epidemic, growing most rapidly in the elderly population. Some of the most devastating sequelae of TBI are related to depressed levels of consciousness (e.g., coma, minimally conscious state) or deficits in executive function. To date, pharmacological and rehabilitative therapies to treat these sequelae are limited. Deep brain stimulation (DBS) has been used to treat a number of pathologies, including Parkinson disease, essential tremor, and epilepsy. Animal and clinical research shows that targets addressing depressed levels of consciousness include components of the ascending reticular activating system and areas of the thalamus. Targets for improving executive function are more varied and include areas that modulate attention and memory, such as the frontal and prefrontal cortex, fornix, nucleus accumbens, internal capsule, thalamus, and some brainstem nuclei. The authors review the literature addressing the use of DBS to treat higher-order cognitive dysfunction and disorders of consciousness in TBI patients, while also offering suggestions on directions for future research.
Topics: Animals; Brain Injuries, Traumatic; Cognition; Consciousness; Deep Brain Stimulation; Epilepsy; Humans; Thalamus
PubMed: 30064315
DOI: 10.3171/2018.5.FOCUS18168 -
Current Biology : CB Jan 2023An interview with Joseph LeDoux, who studies brain mechanisms of emotion, memory, and consciousness.
An interview with Joseph LeDoux, who studies brain mechanisms of emotion, memory, and consciousness.
Topics: Emotions; Brain; Consciousness
PubMed: 36693304
DOI: 10.1016/j.cub.2022.12.010 -
History and Philosophy of the Life... Nov 2021Peter Godfrey-Smith's Metazoa and Joseph LeDoux's The Deep History of Ourselves present radically different big pictures regarding the nature, evolution and distribution... (Review)
Review
Peter Godfrey-Smith's Metazoa and Joseph LeDoux's The Deep History of Ourselves present radically different big pictures regarding the nature, evolution and distribution of consciousness in animals. In this essay review, I discuss the motivations behind these big pictures and try to steer a course between them.
Topics: Animals; Consciousness
PubMed: 34807317
DOI: 10.1007/s40656-021-00472-w -
Science Translational Medicine Aug 2013One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the...
One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the subject's ability to interact with the external environment. Theoretical considerations suggest that consciousness depends on the brain's ability to support complex activity patterns that are, at once, distributed among interacting cortical areas (integrated) and differentiated in space and time (information-rich). We introduce and test a theory-driven index of the level of consciousness called the perturbational complexity index (PCI). PCI is calculated by (i) perturbing the cortex with transcranial magnetic stimulation (TMS) to engage distributed interactions in the brain (integration) and (ii) compressing the spatiotemporal pattern of these electrocortical responses to measure their algorithmic complexity (information). We test PCI on a large data set of TMS-evoked potentials recorded in healthy subjects during wakefulness, dreaming, nonrapid eye movement sleep, and different levels of sedation induced by anesthetic agents (midazolam, xenon, and propofol), as well as in patients who had emerged from coma (vegetative state, minimally conscious state, and locked-in syndrome). PCI reliably discriminated the level of consciousness in single individuals during wakefulness, sleep, and anesthesia, as well as in patients who had emerged from coma and recovered a minimal level of consciousness. PCI can potentially be used for objective determination of the level of consciousness at the bedside.
Topics: Anesthetics; Brain; Consciousness; Evoked Potentials; Female; Humans; Male; Midazolam; Propofol; Transcranial Magnetic Stimulation; Xenon
PubMed: 23946194
DOI: 10.1126/scitranslmed.3006294 -
Neuroscience and Biobehavioral Reviews Feb 2022This review seeks to combine advances in anthropology and neuroscience to investigate the adaptive value of human consciousness. It uses an interdisciplinary perspective... (Review)
Review
This review seeks to combine advances in anthropology and neuroscience to investigate the adaptive value of human consciousness. It uses an interdisciplinary perspective on the origin of consciousness to refute the most common fallacies in considering consciousness, particularly, disregarding the evolutionary origin of the subjective reality in looking for the neural correlates of consciousness and divorcing studies in neuroscience and behavioural sciences. Various explanations linked to consciousness in the field of neuroscience, supplemented with the theoretical explanation of an experience as an ongoing process of overlap between intrinsic neural dynamics and stimulation can be summarised as the stochastic dynamics of one's control system experienced by the individual in the form of subjective reality. This framework elaborates on the world-brain research program and lays foundation for the quantitative description of one's qualitative feelings and naturalistic science of consciousness. Furthermore, this study highlights the philosophical perspective of the inseparability between the physical correlates and the subjective reality contributing to the realistic ontology of conscious processes.
Topics: Brain; Consciousness; Humans; Neurosciences
PubMed: 34942266
DOI: 10.1016/j.neubiorev.2021.12.034 -
Anesthesia and Analgesia Jun 2022
Topics: Consciousness
PubMed: 35595688
DOI: 10.1213/ANE.0000000000005983