Theoretical Models of Consciousness: A Scoping Review

The amount of knowledge on human consciousness has created a multitude of viewpoints and it is difficult to compare and synthesize all the recent scientific perspectives. Indeed, there are many definitions of consciousness and multiple approaches to study the neural correlates of consciousness (NCC). Therefore, the main aim of this article is to collect data on the various theories of consciousness published between 2007–2017 and to synthesize them to provide a general overview of this topic. To describe each theory, we developed a thematic grid called the dimensional model, which qualitatively and quantitatively analyzes how each article, related to one specific theory, debates/analyzes a specific issue. Among the 1130 articles assessed, 85 full texts were included in the prefinal step. Finally, this scoping review analyzed 68 articles that described 29 theories of consciousness. We found heterogeneous perspectives in the theories analyzed. Those with the highest grade of variability are as follows: subjectivity, NCC, and the consciousness/cognitive function. Among sub-cortical structures, thalamus, basal ganglia, and the hippocampus were the most indicated, whereas the cingulate, prefrontal, and temporal areas were the most reported for cortical ones also including the thalamo-cortical system. Moreover, we found several definitions of consciousness and 21 new sub-classifications.

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Behavioral and neural correlates of speech motor sequence learning in stuttering and neurotypical speakers: an fMRI investigation

10.31219/osf.io/62pty ◽

2020 ◽

Author(s):

Matthew Masapollo

Keyword(s):

Basal Ganglia ◽

Motor Learning ◽

Brain Activity ◽

Neurodevelopmental Disorder ◽

Motor Planning ◽

Theoretical Models ◽

Neural Correlates ◽

Motor Sequence ◽

Motor Practice ◽

Speech Motor

Stuttering is a neurodevelopmental disorder characterized by impaired execution of articulatory movements needed for fluent speech production. Existing theoretical models propose that these deficits reflect a malfunction in the cortico-basal-ganglia-thalamocortical (cortico-BG) loop that is responsible for selecting and initiating speech motor programs. However, the cortico-BG loop has also been hypothesized to play a role in speech motor learning. To distinguish motor execution impairments from motor learning impairments in stuttering, the authors examined the behavioral and neural correlates of learning to produce novel phoneme sequences in adults who stutter (AWS) and neurotypical controls. Participants intensively practiced producing pseudowords containing non-native consonant clusters over two days. Results showed that, behaviorally, both AWS and controls produced the words with increased speed and accuracy following motor practice, and the rate of improvement was comparable for the two groups. Using functional magnetic resonance imaging (fMRI), the authors compared brain activity during articulation of the practiced words and a set of novel pseudowords (matched in phonetic complexity). FMRI analyses revealed no differences between AWS and controls in cortical or subcortical regions; both groups showed comparable increases in activation in left-lateralized brain areas implicated in phonological working memory and speech motor planning during production of the novel sequences compared to the practiced sequences. Moreover, activation in left-lateralized basal ganglia sites was negatively correlated with stuttering severity in AWS. Collectively, these findings indicate that AWS exhibit no deficit in learning novel speech sequences but do show impaired execution of these sequences prior to and after learning.

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Somatosensory deficits and neural correlates in cerebral palsy: a scoping review

Developmental Medicine & Child Neurology ◽

10.1111/dmcn.14963 ◽

2021 ◽

Author(s):

Clémentine Brun ◽

Élodie Traverse ◽

Élyse Granger ◽

Catherine Mercier

Keyword(s):

Cerebral Palsy ◽

Scoping Review ◽

Neural Correlates

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Neural correlates of subsequent memory-related gaze reinstatement

10.1101/2021.02.23.432536 ◽

2021 ◽

Author(s):

Jordana S. Wynn ◽

Zhong-Xu Liu ◽

Jennifer D. Ryan

Keyword(s):

Eye Movements ◽

Basal Ganglia ◽

Recognition Memory ◽

Visual Processing ◽

Memory Task ◽

Neural Correlates ◽

Oculomotor Control ◽

Related Activity ◽

Pattern Similarity ◽

Occipital Pole

AbstractMounting evidence linking gaze reinstatement- the recapitulation of encoding-related gaze patterns during retrieval- to behavioral measures of memory suggests that eye movements play an important role in mnemonic processing. Yet, the nature of the gaze scanpath, including its informational content and neural correlates, has remained in question. In the present study, we examined eye movement and neural data from a recognition memory task to further elucidate the behavioral and neural bases of functional gaze reinstatement. Consistent with previous work, gaze reinstatement during retrieval of freely-viewed scene images was greater than chance and predictive of recognition memory performance. Gaze reinstatement was also associated with viewing of informationally salient image regions at encoding, suggesting that scanpaths may encode and contain high-level scene content. At the brain level, gaze reinstatement was predicted by encoding-related activity in the occipital pole and basal ganglia, neural regions associated with visual processing and oculomotor control. Finally, cross-voxel brain pattern similarity analysis revealed overlapping subsequent memory and subsequent gaze reinstatement modulation effects in the parahippocampal place area and hippocampus, in addition to the occipital pole and basal ganglia. Together, these findings suggest that encoding-related activity in brain regions associated with scene processing, oculomotor control, and memory supports the formation, and subsequent recapitulation, of functional scanpaths. More broadly, these findings lend support to Scanpath Theory’s assertion that eye movements both encode, and are themselves embedded in, mnemonic representations.

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Neural correlates of cognitive function and symptoms in attention-deficit/hyperactivity disorder in adults

NeuroImage Clinical ◽

10.1016/j.nicl.2018.04.035 ◽

2018 ◽

Vol 19 ◽

pp. 374-383 ◽

Cited By ~ 9

Author(s):

Kuaikuai Duan ◽

Jiayu Chen ◽

Vince D. Calhoun ◽

Dongdong Lin ◽

Wenhao Jiang ◽

...

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Cognitive Function ◽

Attention Deficit ◽

Neural Correlates ◽

Hyperactivity Disorder

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Cognitive and Affective Empathy in Huntington’s Disease

Journal of Huntington s Disease ◽

10.3233/jhd-210469 ◽

2021 ◽

pp. 1-12

Author(s):

Arnau Puig-Davi ◽

Saul Martinez-Horta ◽

Frederic Sampedro ◽

Andrea Horta-Barba ◽

Jesus Perez-Perez ◽

...

Keyword(s):

Basal Ganglia ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Cognitive Deficits ◽

Perspective Taking ◽

Neural Correlates ◽

Affective Empathy ◽

Grey Matter Volume ◽

Empathy Deficits ◽

Almost All

Background: Empathy is a multidimensional construct and a key component of social cognition. In Huntington’s disease (HD), little is known regarding the phenomenology and the neural correlates of cognitive and affective empathy, and regarding how empathic deficits interact with other behavioral and cognitive manifestations. Objective: To explore the cognitive and affective empathy disturbances and related behavioral and neural correlates in HD. Methods: Clinical and sociodemographic data were obtained from 36 healthy controls (HC) and 54 gene-mutation carriers (17 premanifest and 37 early-manifest HD). The Test of Cognitive and Affective Empathy (TECA) was used to characterize cognitive (CE) and affective empathy (AE), and to explore their associations with grey matter volume (GMV) and cortical thickness (Cth). Results: Compared to HC, premanifest participants performed significantly worse in perspective taking (CE) and empathic distress (AE). In symptomatic participants, scores were significantly lower in almost all the TECA subscales. Several empathy subscales were associated with the severity of apathy, irritability, and cognitive deficits. CE was associated with GMV in thalamic, temporal, and occipital regions, and with Cth in parietal and temporal areas. AE was associated with GMV in the basal ganglia, limbic, occipital, and medial orbitofrontal regions, and with Cth in parieto-occipital areas. Conclusion: Cognitive and affective empathy deficits are detectable early, are more severe in symptomatic participants, and involve the disruption of several fronto-temporal, parieto-occipital, basal ganglia, and limbic regions. These deficits are associated with disease severity and contribute to several behavioral symptoms, facilitating the presentation of maladaptive patterns of social interaction.

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The Effects of Cannabis Use on Cognitive Function in Healthy Aging: A Systematic Scoping Review

Archives of Clinical Neuropsychology ◽

10.1093/arclin/acaa105 ◽

2020 ◽

Author(s):

Nina Pocuca ◽

T Jordan Walter ◽

Arpi Minassian ◽

Jared W Young ◽

Mark A Geyer ◽

...

Keyword(s):

Cognitive Function ◽

Scoping Review ◽

Healthy Aging ◽

Web Of Science ◽

Cannabis Use ◽

Future Research ◽

Meta Analyses ◽

Older Populations ◽

The Relationship ◽

Chronic Doses

Abstract Background Older adults (≥50 years) represent the fastest-growing population of people who use cannabis, potentially due to the increasing promotion of cannabis as medicine by dispensaries and cannabis websites. Given healthy aging and cannabis use are both associated with cognitive decline, it is important to establish the effects of cannabis on cognition in healthy aging. Objective This systematic scoping review used preferred reporting items for systematic reviews and meta-analyses guidelines to critically examine the extent of literature on this topic and highlight areas for future research. Method A search of six databases (PubMed, EMBASE, PsycINFO, Web of Science, Family and Society Studies Worldwide, and CINAHL) for articles published by September 2019, yielded 1,014 unique results. Results Six articles reported findings for older populations (three human and three rodent studies), highlighting the paucity of research in this area. Human studies revealed largely null results, likely due to several methodological limitations. Better-controlled rodent studies indicate that the relationship between ∆9-tetrahydrocannabinol (THC) and cognitive function in healthy aging depends on age and level of THC exposure. Extremely low doses of THC improved cognition in very old rodents. Somewhat higher chronic doses improved cognition in moderately aged rodents. No studies examined the effects of cannabidiol (CBD) or high-CBD cannabis on cognition. Conclusions This systematic scoping review provides crucial, timely direction for future research on this emerging issue. Future research that combines neuroimaging and cognitive assessment would serve to advance understanding of the effects of age and quantity of THC and CBD on cognition in healthy aging.

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Are dietary supplements and nutraceuticals effective for musculoskeletal health and cognitive function? A scoping review

The journal of nutrition health & aging ◽

10.1007/s12603-016-0823-x ◽

2016 ◽

Vol 21 (5) ◽

pp. 527-538 ◽

Cited By ~ 25

Author(s):

G. Iolascon ◽

R. Gimigliano ◽

M. Bianco ◽

A. de Sire ◽

A. Moretti ◽

...

Keyword(s):

Cognitive Function ◽

Dietary Supplements ◽

Scoping Review ◽

Musculoskeletal Health

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Pathophysiological Mechanisms

10.1093/med/9780190259600.003.0008 ◽

2016 ◽

Author(s):

Erwin B. Montgomery

Keyword(s):

Nervous System ◽

Basal Ganglia ◽

Mechanisms Of Action ◽

Normal Function ◽

Pathophysiological Mechanisms ◽

Loosely Coupled ◽

Therapeutic Mechanism ◽

Novel Theory ◽

Cortical System ◽

High Beta

Pathophysiology is central to neuroscience and psychiatry for a number of reasons. Indeed, nearly every inference to normal function of the nervous system is derived from notions of pathophysiology. Understanding DBS’s mechanisms of action—a therapeutic mechanism, particularly—greatly depends on the prior informing conception of pathophysiology. Several current theories of pathophysiology are critically reviewed such as the GPi Rate, high beta oscillations, excessive bursting and hypersynchronization theories. A novel theory offered that introduces the concept of the basal ganglia-thalamic-cortical system as a network of loosely coupled nonlinear polysynaptic reentrant oscillators.

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