scholarly journals Regulating the Access to Awareness: Brain Activity Related to Probe-related and Spontaneous Reversals in Binocular Rivalry

2017 ◽  
Vol 29 (6) ◽  
pp. 1089-1102 ◽  
Author(s):  
Brian A. Metzger ◽  
Kyle E. Mathewson ◽  
Evelina Tapia ◽  
Monica Fabiani ◽  
Gabriele Gratton ◽  
...  
Keyword(s):  
Binocular Rivalry ◽  
Stimulus Change ◽  
Brain Activity ◽  
Visual Awareness ◽  
Intermediate Stage ◽  
Neural Correlates ◽  
Brain Regions ◽  
Conscious Awareness ◽  
Network Properties ◽  
Per Se

Research on the neural correlates of consciousness (NCC) has implicated an assortment of brain regions, ERP components, and network properties associated with visual awareness. Recently, the P3b ERP component has emerged as a leading NCC candidate. However, typical P3b paradigms depend on the detection of some stimulus change, making it difficult to separate brain processes elicited by the stimulus itself from those associated with updates or changes in visual awareness. Here we used binocular rivalry to ask whether the P3b is associated with changes in awareness even in the absence of changes in the object of awareness. We recorded ERPs during a probe-mediated binocular rivalry paradigm in which brief probes were presented over the image in either the suppressed or dominant eye to determine whether the elicited P3b activity is probe or reversal related. We found that the timing of P3b (but not its amplitude) was closely related to the timing of the report of a perceptual change rather than to the onset of the probe. This is consistent with the proposal that P3b indexes updates in conscious awareness, rather than being related to stimulus processing per se. Conversely, the probe-related P1 amplitude (but not its latency) was associated with reversal latency, suggesting that the degree to which the probe is processed increases the likelihood of a fast perceptual reversal. Finally, the response-locked P3b amplitude (but not its latency) was associated with the duration of an intermediate stage between reversals in which parts of both percepts coexist (piecemeal period). Together, the data suggest that the P3b reflects an update in consciousness and that the intensity of that process (as indexed by P3b amplitude) predicts how immediate that update is.

Auditory verbal hallucinations: neuroimaging and treatment

2016 ◽  
Vol 47 (2) ◽  
pp. 199-208 ◽  
Author(s):  
M. M. Bohlken ◽  
K. Hugdahl ◽  
I. E. C. Sommer
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Neural Correlates ◽  
Brain Regions ◽  
Behavioural Therapy ◽  
Special Focus ◽  
Comprehensive Overview ◽  
Auditory Verbal Hallucinations ◽  
Research Areas ◽  
Control Functions

Auditory verbal hallucinations (AVH) are a frequently occurring phenomenon in the general population and are considered a psychotic symptom when presented in the context of a psychiatric disorder. Neuroimaging literature has shown that AVH are subserved by a variety of alterations in brain structure and function, which primarily concentrate around brain regions associated with the processing of auditory verbal stimuli and with executive control functions. However, the direction of association between AVH and brain function remains equivocal in certain research areas and needs to be carefully reviewed and interpreted. When AVH have significant impact on daily functioning, several efficacious treatments can be attempted such as antipsychotic medication, brain stimulation and cognitive–behavioural therapy. Interestingly, the neural correlates of these treatments largely overlap with brain regions involved in AVH. This suggests that the efficacy of treatment corresponds to a normalization of AVH-related brain activity. In this selected review, we give a compact yet comprehensive overview of the structural and functional neuroimaging literature on AVH, with a special focus on the neural correlates of efficacious treatment.

Simulated Driving and Brain Imaging: Combining Behavior, Brain Activity, and Virtual Reality

CNS Spectrums ◽  
2006 ◽  
Vol 11 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Kara N. Carvalho ◽  
Godfrey D. Pearlson ◽  
Robert S. Astur ◽  
Vince D. Calhoun
Keyword(s):  
Virtual Reality ◽  
Brain Function ◽  
Driving Simulator ◽  
Alcohol Intoxication ◽  
Brain Activity ◽  
Neural Correlates ◽  
Brain Regions ◽  
Blood Levels ◽  
Imaging Data ◽  
Simulated Driving

ABSTRACTIntroduction:Virtual reality in the form of simulated driving is a useful tool for studying the brain. Various clinical questions can be addressed, including both the role of alcohol as a modulator of brain function and regional brain activation related to elements of driving.Objective:We reviewed a study of the neural correlates of alcohol intoxication through the use of a simulated-driving paradigm and wished to demonstrate the utility of recording continuous-driving behavior through a new study using a programmable driving simulator developed at our center.Methods:Functional magnetic resonance imaging data was collected from subjects while operating a driving simulator. Independent component analysis (ICA) was used to analyze the data. Specific brain regions modulated by alcohol, and relationships between behavior, brain function, and alcohol blood levels were examined with aggregate behavioral measures. Fifteen driving epochs taken from two subjects while also recording continuously recorded driving variables were analyzed with ICA.Results:Preliminary findings reveal that four independent components correlate with various aspects of behavior. An increase in braking while driving was found to increase activation in motor areas, while cerebellar areas showed signal increases during steering maintenance, yet signal decreases during steering changes. Additional components and significant findings are further outlined.Conclusion:In summary, continuous behavioral variables conjoined with ICA may offer new insight into the neural correlates of complex human behavior.

scholarly journals Early and Contemporary Human Neuroimaging Studies of Serotonergic Psychedelics

2020 ◽  
Author(s):  
Enzo Tagliazucchi
Keyword(s):  
Human Subjects ◽  
Brain Activity ◽  
Neural Correlates ◽  
The Self ◽  
Conscious Awareness ◽  
Altered Consciousness ◽  
Healthy Human ◽  
Non Invasive ◽  
Healthy Human Subjects ◽  
Human Neuroimaging

Serotonergic psychedelics are known to elicit changes in conscious awareness, including perception of the environment and the self, as well as in mood, emotion and different aspects of cognition (Nichols, 2016). The effect of these compounds is complex and resists a straightforward classification that is useful for other drugs, such as “stimulants” or “sedatives”. While the effects of certain psychedelics do have a stimulant dimension, their defining characteristic is the capacity to temporarily induce a state of altered consciousness. Because of this, the study of psychedelics cannot be based only on animal models, since humans are alone in their capacity to explicitly report the contents of their conscious awareness. Psychedelic research with healthy human subjects necessitates techniques for the non-invasive recording of brain activity or its physiological and metabolic correlates. These techniques are referred to as “neuroimaging”, and here we review their application in the study of the neural correlates of altered consciousness induced by serotonergic psychedelics.

scholarly journals Neuronal Oscillatory Signatures of Joint Attention and Intersubjectivity in Arrhythmic Coaction

2021 ◽  
Vol 15 ◽  
Author(s):  
Alexander Maÿe ◽  
Tiezhi Wang ◽  
Andreas K. Engel
Keyword(s):  
Executive Control ◽  
Emotional Processing ◽  
Subjective Experience ◽  
Phase Synchronization ◽  
Specific Activity ◽  
Brain Activity ◽  
Neural Correlates ◽  
Brain Regions ◽  
Music Making ◽  
The Brain

Hyper-brain studies analyze the brain activity of two or more individuals during some form of interaction. Several studies found signs of inter-subject brain activity coordination, such as power and phase synchronization or information flow. This hyper-brain coordination is frequently studied in paradigms which induce rhythms or even synchronization, e.g., by mirroring movements, turn-based activity in card or economic games, or joint music making. It is therefore interesting to figure out in how far coordinated brain activity may be induced by a rhythmicity in the task and/or the sensory feedback that the partners receive. We therefore studied the EEG brain activity of dyads in a task that required the smooth pursuit of a target and did not involve any extrinsic rhythms. Partners controlled orthogonal axes of the two-dimensional motion of an object that had to be kept on the target. Using several methods for analyzing hyper-brain coupling, we could not detect signs of coordinated brain activity. However, we found several brain regions in which the frequency-specific activity significantly correlated with the objective task performance, the subjective experience thereof, and of the collaboration. Activity in these regions has been linked to motor control, sensorimotor integration, executive control and emotional processing. Our results suggest that neural correlates of intersubjectivity encompass large parts of brain areas that are considered to be involved in sensorimotor control without necessarily coordinating their activity across agents.

scholarly journals Alpha fluctuations regulate the accrual of visual information to awareness

2020 ◽  
Author(s):  
Mireia Torralba ◽  
Alice Drew ◽  
Alba Sabaté San José ◽  
Luis Morís Fernández ◽  
Salvador Soto-Faraco
Keyword(s):  
Binocular Rivalry ◽  
Visual Information ◽  
Brain Activity ◽  
Visual Awareness ◽  
Sensory Information ◽  
Occipital Cortex ◽  
Visual Inputs ◽  
Perceptual Alternation ◽  
Eeg Recordings ◽  
The Individual

AbstractEndogenous brain processes play a paramount role in shaping up perceptual phenomenology, as illustrated by the alternations experienced by humans (and other animals) when watching perceptually ambiguous, static images. Here, we hypothesised that endogenous alpha fluctuations in the visual cortex pace the accumulation of sensory information leading to perceptual outcomes. We addressed this hypothesis using binocular rivalry combined with visual entrainment and electroencephalography in humans (42 female, 40 male). The results revealed a correlation between the individual frequency of alpha oscillations in the occipital cortex and perceptual alternation rates experienced during binocular rivalry. In subsequent experiments we show that regulating endogenous brain activity via entrainment produced corresponding changes in perceptual alternation rate, which were observed only in the alpha range but not at lower entrainment frequencies. Overall, rhythmic alpha stimulation resulted in faster perceptual alternation rates, compared to arrhythmic or no stimulation. These findings support the notion that visual information is accumulated via alpha cycles to promote the emergence of conscious perceptual representations. We suggest that models of binocular rivalry incorporating posterior alpha as a pacemaker can provide an important advance in the comprehension of the dynamics of visual awareness.Significance statementMainstream theories in cognitive neuroscience agree that endogenous brain processes play a paramount role in shaping our perceptual experience of sensory inputs. In vision, endogenous fluctuations in the alpha rhythm have been pointed out to regulate visual inputs to perception. In support of this hypothesis, here we used EEG recordings and visual entrainment to demonstrate that inter-individual differences in the speed of endogenous alpha fluctuations in the brain are causally related to the accrual of visual information to awareness. These findings provide, for the first time, evidence for alpha-gated regulation of the dynamics of alternations in conscious visual perception.

scholarly journals Parcellation-induced variation of empirical and simulated brain connectomes at group and subject levels

2021 ◽  
pp. 1-56
Author(s):  
Justin W.M. Domhof ◽  
Kyesam Jung ◽  
Simon B. Eickhoff ◽  
Oleksandr V. Popovych
Keyword(s):  
Functional Connectivity ◽  
Goodness Of Fit ◽  
Brain Activity ◽  
Brain Regions ◽  
Single Subject ◽  
Whole Brain ◽  
Clear Cut ◽  
Recent Developments ◽  
Network Properties ◽  
Brain Models

Abstract Recent developments of whole-brain models have demonstrated their potential when investigating resting-state brain activity. However, it has not been systematically investigated how alternating derivations of the empirical structural and functional connectivity, serving as the model input, from MRI data influence modelling results. Here, we study the influence from one major element: the brain parcellation scheme that reduces the dimensionality of brain networks by grouping thousands of voxels into a few hundred brain regions. We show graph-theoretical statistics derived from the empirical data and modelling results exhibiting a high heterogeneity across parcellations. Furthermore, the network properties of empirical brain connectomes explain the lion’s share of the variance in the modelling results with respect to the parcellation variation. Such a clear-cut relationship is not observed at the subject-resolved level per parcellation. Finally, the graph-theoretical statistics of the simulated connectome correlate with those of the empirical functional connectivity across parcellations. However, this relation is not one-to-one, and its precision can vary between models. Our results imply that network properties of both empirical connectomes can explain the goodness-of-fit of whole-brain models toempirical data at a global group but not a single-subject level, which provides further insights into the personalisation of whole-brain models.

Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Processes ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Semantic Retrieval ◽  
Age Related ◽  
The Face ◽  
Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

No impact of affective person knowledge on visual awareness: Evidence from binocular rivalry and continuous flash suppression.

Emotion ◽  
2017 ◽  
Vol 17 (8) ◽  
pp. 1199-1207 ◽  
Author(s):  
Timo Stein ◽  
Caitlyn Grubb ◽  
Maria Bertrand ◽  
Seh Min Suh ◽  
Sara C. Verosky
Keyword(s):  
Binocular Rivalry ◽  
Visual Awareness ◽  
Continuous Flash Suppression

Comparative analysis of changes of bioelectrical activity of the brain during the neutral touch and during the performance of the myofascial release technique

2018 ◽  
pp. 46-55
Author(s):  
A. F. Belyaev ◽  
G. E. Piskunova
Keyword(s):  
Soft Tissue ◽  
Brain Activity ◽  
Direct Action ◽  
Brain Regions ◽  
Therapeutic Touch ◽  
Bioelectrical Activity ◽  
Therapeutic Action ◽  
Osteopathic Treatment ◽  
The Difference ◽  
Multiparameter Analysis

Introduction. One of the main tools of an osteopath are soft tissue techniques, which have a number of particular qualities such as minimization of force and duration of indirect techniques with an emphasis on muscle and ligamentous structures; combination of gestures, tendency to maximal relaxation and exclusion of direct action on pathological symptoms such as tension, overtone and pain. Minimization of the force applied during the performance of soft tissue techniques often invites a question whether there are differences between the usual touch and the therapeutic touch of an osteopath.Goal of research - to reveal the changes in the bioelectrical activity of the cerebral cortex arising in the process of osteopathic treatment in order to prove its specifi city in comparison with nonspecifi c tactile stimulation (neutral touch).Materials and methods. 75 people were examined with the use of multiparameter analysis of multichannel EEG in different times. 25 patients were clinically healthy adults, whereas 50 patients had signs of somatic dysfunctions.Results. Computer encephalography permits to perceive the difference between the neutral touch and the therapeutic action. An identifi cation reaction is a response to the neutral touch (changes in brain bioelectrical activity with an increase in statistically signifi cant connections in the temporal lobes), whereas the therapeutic action provokes the state of purposeful brain activity during still point (intensifi cation of frontooccipital interactions).Conclusions. Osteopathic action causes additional tension in the processing of incoming information, which requires participation of different brain regions, including interhemispheric mechanisms associated with analysis, maintenance of attention and regulation of targeted activities.

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