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Neuroscience and Biobehavioral Reviews May 2019Lucid dreaming refers to the phenomenon of becoming aware of the fact that one is dreaming during ongoing sleep. Despite having been physiologically validated for... (Review)
Review
Lucid dreaming refers to the phenomenon of becoming aware of the fact that one is dreaming during ongoing sleep. Despite having been physiologically validated for decades, the neurobiology of lucid dreaming is still incompletely characterized. Here we review the neuroscientific literature on lucid dreaming, including electroencephalographic, neuroimaging, brain lesion, pharmacological and brain stimulation studies. Electroencephalographic studies of lucid dreaming are mostly underpowered and show mixed results. Neuroimaging data is scant but preliminary results suggest that prefrontal and parietal regions are involved in lucid dreaming. A focus of research is also to develop methods to induce lucid dreams. Combining training in mental set with cholinergic stimulation has shown promising results, while it remains unclear whether electrical brain stimulation could be used to induce lucid dreams. Finally, we discuss strategies to measure lucid dreaming, including best-practice procedures for the sleep laboratory. Lucid dreaming has clinical and scientific applications, and shows emerging potential as a methodology in the cognitive neuroscience of consciousness. Further research with larger sample sizes and refined methodology is needed.
Topics: Awareness; Brain; Brain Mapping; Brain Waves; Cognitive Neuroscience; Dreams; Humans; Magnetic Resonance Imaging; Metacognition; Transcranial Direct Current Stimulation
PubMed: 30880167
DOI: 10.1016/j.neubiorev.2019.03.008 -
Trends in Neurosciences Jan 2020Ordinary human experience is embedded in a web of causal relations that link the brain to the body and the wider environment. However, there might be conditions in which... (Review)
Review
Ordinary human experience is embedded in a web of causal relations that link the brain to the body and the wider environment. However, there might be conditions in which brain activity supports consciousness even when that activity is fully causally isolated from the body and its environment. Such cases would involve what we call islands of awareness: conscious states that are neither shaped by sensory input nor able to be expressed by motor output. This Opinion paper considers conditions in which such islands might occur, including ex cranio brains, hemispherotomy, and in cerebral organoids. We examine possible methods for detecting islands of awareness, and consider their implications for ethics and for the nature of consciousness.
Topics: Awareness; Brain; Consciousness; Humans
PubMed: 31836316
DOI: 10.1016/j.tins.2019.11.003 -
Neuroscience and Biobehavioral Reviews Dec 2017Self-awareness is a pivotal component of conscious experience. It is correlated with a paralimbic network of medial prefrontal/anterior cingulate and medial... (Review)
Review
Self-awareness is a pivotal component of conscious experience. It is correlated with a paralimbic network of medial prefrontal/anterior cingulate and medial parietal/posterior cingulate cortical "hubs" and associated regions. Electromagnetic and transmitter manipulation have demonstrated that the network is not an epiphenomenon but instrumental in generation of self-awareness. Thus, transcranial magnetic stimulation (TMS) targeting the hubs impedes different aspects of self-awareness with a latency of 160ms. The network is linked by ∼40Hz oscillations and regulated by dopamine. The oscillations are generated by rhythmic GABA-ergic inhibitory activity in interneurons with an extraordinarily high metabolic rate. The hubs are richly endowed with interneurons and therefore highly vulnerable to disturbed energy supply. Consequently, deficient paralimbic activity and self-awareness are characteristic features of many disorders with impaired oxygen homeostasis. Such disorders may therefore be treated unconventionally by targeting interneuron function.
Topics: Awareness; Brain Waves; Cognition; Cognitive Neuroscience; Consciousness; Humans; Self Concept; Transcranial Magnetic Stimulation
PubMed: 27079562
DOI: 10.1016/j.neubiorev.2016.04.004 -
Neural Plasticity 2016Knowledge of the body is filtered by perceptual information, recalibrated through predominantly innate stored information, and neurally mediated by direct sensory motor... (Review)
Review
Knowledge of the body is filtered by perceptual information, recalibrated through predominantly innate stored information, and neurally mediated by direct sensory motor information. Despite multiple sources, the immediate prediction, construction, and evaluation of one's body are distorted. The origins of such distortions are unclear. In this review, we consider three possible sources of awareness that inform body distortion. First, the precision in the body metric may be based on the sight and positioning sense of a particular body segment. This view provides information on the dual nature of body representation, the reliability of a conscious body image, and implicit alterations in the metrics and positional correspondence of body parts. Second, body awareness may reflect an innate organizational experience of unity and continuity in the brain, with no strong isomorphism to body morphology. Third, body awareness may be based on efferent/afferent neural signals, suggesting that major body distortions may result from changes in neural sensorimotor experiences. All these views can be supported empirically, suggesting that body awareness is synthesized from multimodal integration and the temporal constancy of multiple body representations. For each of these views, we briefly discuss abnormalities and therapeutic strategies for correcting the bodily distortions in various clinical disorders.
Topics: Awareness; Body Dysmorphic Disorders; Body Image; Humans; Neuronal Plasticity; Transcranial Magnetic Stimulation
PubMed: 27630779
DOI: 10.1155/2016/9834340 -
Neuroscience and Biobehavioral Reviews Nov 2014Oral somatosensory awareness refers to the somatic sensations arising within the mouth, and to the information these sensations provide about the state and structure of... (Review)
Review
Oral somatosensory awareness refers to the somatic sensations arising within the mouth, and to the information these sensations provide about the state and structure of the mouth itself, and objects in the mouth. Because the oral tissues have a strong somatosensory innervation, they are the locus of some of our most intense and vivid bodily experiences. The salient pain of toothache, or the habit of running one's tongue over one's teeth when someone mentions "dentist", provide two very different indications of the power of oral somatosensory awareness in human experience and behaviour. This paper aims to review the origins and structure of oral somatosensory awareness, focussing on quantitative, mechanistic studies in humans. We first extend a model of levels of bodily awareness to the specific case of the mouth. We then briefly summarise the sensory innervation of oral tissues, and their projections in the brain. We next describe how these peripheral inputs give rise to perceptions of objects in the mouth, such as foods, liquids and oral devices, and also of the mouth tissues themselves. Finally, we consider the concept of a conscious mouth image, and the somatosensory basis of "mouth feel". The theoretical framework outlined in this paper is intended to facilitate scientific studies of this important site of human experience.
Topics: Awareness; Humans; Mouth; Touch; Touch Perception
PubMed: 25284337
DOI: 10.1016/j.neubiorev.2014.09.015 -
Cognitive, Affective & Behavioral... Jun 2021Monitoring for errors and behavioral adjustments after errors are essential for daily life. A question that has not been addressed systematically yet, is whether...
Monitoring for errors and behavioral adjustments after errors are essential for daily life. A question that has not been addressed systematically yet, is whether consciously perceived errors lead to different behavioral adjustments compared to unperceived errors. Our goal was to develop a task that would enable us to study different commonly observed neural correlates of error processing and post-error adjustments in their relation to error awareness and accuracy confidence in a single experiment. We assessed performance in a new number judgement error awareness task in 70 participants. We used multiple, robust, single-trial EEG regressions to investigate the link between neural correlates of error processing (e.g., error-related negativity (ERN) and error positivity (Pe)) and error awareness. We found that only aware errors had a slowing effect on reaction times in consecutive trials, but this slowing was not accompanied by post-error increases in accuracy. On a neural level, error awareness and confidence had a modulating effect on both the ERN and Pe, whereby the Pe was most predictive of participants' error awareness. Additionally, we found partial support for a mediating role of error awareness on the coupling between the ERN and behavioral adjustments in the following trial. Our results corroborate previous findings that show both an ERN/Pe and a post-error behavioral adaptation modulation by error awareness. This suggests that conscious error perception can support meta-control processes balancing the recruitment of proactive and reactive control. Furthermore, this study strengthens the role of the Pe as a robust neural index of error awareness.
Topics: Awareness; Electroencephalography; Evoked Potentials; Humans; Mental Processes; Psychomotor Performance; Reaction Time
PubMed: 33025512
DOI: 10.3758/s13415-020-00838-w -
Consciousness and Cognition May 2015Are individuals responsible for behaviour that is implicitly biased? Implicitly biased actions are those which manifest the distorting influence of implicit... (Review)
Review
Are individuals responsible for behaviour that is implicitly biased? Implicitly biased actions are those which manifest the distorting influence of implicit associations. That they express these 'implicit' features of our cognitive and motivational make up has been appealed to in support of the claim that, because individuals lack the relevant awareness of their morally problematic discriminatory behaviour, they are not responsible for behaving in ways that manifest implicit bias. However, the claim that such influences are implicit is, in fact, not straightforwardly related to the claim that individuals lack awareness of the morally problematic dimensions of their behaviour. Nor is it clear that lack of awareness does absolve from responsibility. This may depend on whether individuals culpably fail to know something that they should know. I propose that an answer to this question, in turn, depends on whether other imperfect cognitions are implicated in any lack of the relevant kind of awareness. In this paper I clarify our understanding of 'implicitly biased actions' and then argue that there are three different dimensions of awareness that might be at issue in the claim that individuals lack awareness of implicit bias. Having identified the relevant sense of awareness I argue that only one of these senses is defensibly incorporated into a condition for responsibility, rejecting recent arguments from Washington & Kelly for an 'externalist' epistemic condition. Having identified what individuals should - and can - know about their implicitly biased actions, I turn to the question of whether failures to know this are culpable. This brings us to consider the role of implicit biases in relation to other imperfect cognitions. I conclude that responsibility for implicitly biased actions may depend on answers to further questions about their relationship to other imperfect cognitions.
Topics: Awareness; Cognition; Humans; Knowledge; Morals
PubMed: 25467778
DOI: 10.1016/j.concog.2014.08.024 -
Journal of Neurophysiology Apr 2022In a recent article published in titled "Sensitivity to changes in rate of heartbeats as a measure of interoceptive ability," Larsson et al. ( 126: 1799-1813, 2021)... (Review)
Review
In a recent article published in titled "Sensitivity to changes in rate of heartbeats as a measure of interoceptive ability," Larsson et al. ( 126: 1799-1813, 2021) introduce a new method to evaluate the interoceptive ability and report a surprising tendency in humans to perceive fewer heartbeats during spontaneous increases in resting heart rate. The authors argue that this result reflects a reduction in the strength of the heartbeat during the inspiration periods. Here, we discuss this finding and propose a complementary interpretation grounded on consciousness research and an emerging literature showing the influence of the breathing phase on perception and brain activity at rest.
Topics: Awareness; Consciousness; Heart Rate; Humans; Interoception; Respiration; Respiratory Rate
PubMed: 35294271
DOI: 10.1152/jn.00027.2022 -
Neurobiology of Aging Jul 2020Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current...
Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults. Greater right parietal functional magnetic resonance imaging activation was associated with higher levels of contingency awareness for younger and older subjects. Cathodal transcranial direct current stimulation over the right parietal lobe led to lower levels of awareness in younger subjects without disrupting conditioned responses. Older adults exhibited hyperactivations in the parietal and medial temporal lobes, despite showing no conditioning deficits. These findings strongly support the idea that the parietal cortex serves as a substrate for contingency awareness and that age-related disruption of this region is sufficient to impair awareness, which may be a manifestation of some form of naturally occurring age-related neglect.
Topics: Adult; Aged; Aging; Awareness; Blinking; Conditioning, Classical; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parietal Lobe; Temporal Lobe; Transcranial Direct Current Stimulation; Young Adult
PubMed: 32241582
DOI: 10.1016/j.neurobiolaging.2020.02.024 -
Philosophical Transactions of the Royal... May 2014Understanding consciousness is a major scientific challenge of our times, and perceptual awareness is an integral part of that challenge. This Theme Issue aims to...
Understanding consciousness is a major scientific challenge of our times, and perceptual awareness is an integral part of that challenge. This Theme Issue aims to provide a timely focus on crucial insights from leading scientists on perceptual awareness and its neural basis. The issue refers to key research questions and findings in perceptual awareness research and aims to be a catalyst for further research, by bringing together the state-of-the-art. It shows how bridges are being built between empirical and theoretical research and proposes new directions for the study of multisensory awareness and the role of the states of the body therein. In this introduction, we highlight crucial problems that have characterized the development of the study of perceptual awareness. We then provide an overview of major experimental and theoretical paradigms related to perceptual awareness and its neural basis. Finally, we present an overview of the Theme Issue, with reference to the contributed articles and their relationships.
Topics: Awareness; Brain; Consciousness; Humans; Models, Psychological; Perception
PubMed: 24639576
DOI: 10.1098/rstb.2013.0203