scholarly journals From visual awareness to consciousness without sensory input: The role of spontaneous brain activity

2020 ◽  
Vol 37 (3-4) ◽  
pp. 216-219
Author(s):  
Marine Vernet ◽  
Romain Quentin ◽  
Shruti Japee ◽  
Leslie G. Ungerleider
Keyword(s):  
Sensory Input ◽  
Brain Activity ◽  
Visual Awareness ◽  
Spontaneous Brain Activity

The role of sub-second neural events in spontaneous brain activity

2015 ◽  
Vol 32 ◽  
pp. 24-30 ◽  
Author(s):  
Esther Florin ◽  
Masataka Watanabe ◽  
Nikos K Logothetis
Keyword(s):  
Brain Activity ◽  
Spontaneous Brain Activity

The Bodily Self in Schizophrenia

2018 ◽  
pp. 1108-1124
Author(s):  
Francesca Ferri ◽  
Vittorio Gallese
Keyword(s):  
Empirical Evidence ◽  
Multisensory Processing ◽  
Brain Activity ◽  
Sense Of Agency ◽  
Body Ownership ◽  
Temporal Binding ◽  
Spontaneous Brain Activity ◽  
Temporal Binding Window ◽  
Body Experiences

This chapter illustrates the most recent empirical evidence of anomalies of body experiences in schizophrenia and schizotypy, with a specific focus on body ownership, sense of agency, and self-other boundary. The authors link these anomalies of body experiences to a reduced temporal sensitivity of multisensory processing, as indexed by an abnormally wide temporal binding window, which has been reported in both schizophrenia and schizotypy. Then, the authors propose specific neurobiological markers possibly associated with temporal anomalies of multisensory processing and, consequently, body experiences in schizophrenia and schizotypy. They refer specifically to the role of disorganized patterns of spontaneous brain activity, and the underlying excitation/inhibition imbalance, as a possible key to understanding anomalies of bodily-self experiences in self-disorders.

scholarly journals How do the blind ‘see’? The role of spontaneous brain activity in self-generated perception

Brain ◽  
2020 ◽  
Author(s):  
Avital Hahamy ◽  
Meytal Wilf ◽  
Boris Rosin ◽  
Marlene Behrmann ◽  
Rafael Malach
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Brain Activity ◽  
Visual Hallucinations ◽  
Charles Bonnet Syndrome ◽  
Spontaneous Brain Activity ◽  
Visual Hierarchy ◽  
Early Visual Cortex ◽  
Spontaneous Fluctuations

Abstract Spontaneous activity of the human brain has been well documented, but little is known about the functional role of this ubiquitous neural phenomenon. It has previously been hypothesized that spontaneous brain activity underlies unprompted (internally generated) behaviour. We tested whether spontaneous brain activity might underlie internally-generated vision by studying the cortical visual system of five blind/visually-impaired individuals who experience vivid visual hallucinations (Charles Bonnet syndrome). Neural populations in the visual system of these individuals are deprived of external input, which may lead to their hyper-sensitization to spontaneous activity fluctuations. To test whether these spontaneous fluctuations can subserve visual hallucinations, the functional MRI brain activity of participants with Charles Bonnet syndrome obtained while they reported their hallucinations (spontaneous internally-generated vision) was compared to the: (i) brain activity evoked by veridical vision (externally-triggered vision) in sighted controls who were presented with a visual simulation of the hallucinatory streams; and (ii) brain activity of non-hallucinating blind controls during visual imagery (cued internally-generated vision). All conditions showed activity spanning large portions of the visual system. However, only the hallucination condition in the Charles Bonnet syndrome participants demonstrated unique temporal dynamics, characterized by a slow build-up of neural activity prior to the reported onset of hallucinations. This build-up was most pronounced in early visual cortex and then decayed along the visual hierarchy. These results suggest that, in the absence of external visual input, a build-up of spontaneous fluctuations in early visual cortex may activate the visual hierarchy, thereby triggering the experience of vision.

scholarly journals Increased insula activity precedes the formation of subjective Gestalt

2022 ◽  
Author(s):  
Marilena Wilding ◽  
Christof Koerner ◽  
Anja Ischebeck ◽  
Natalia Zaretskaya
Keyword(s):  
Sensory Input ◽  
Brain Activity ◽  
Human Perception ◽  
Resting State Fmri ◽  
Stimulus Onset ◽  
Neural Mechanisms ◽  
Superior Parietal Cortex ◽  
Increased Activity ◽  
Rare Opportunity

The constructive nature of human perception sometimes leads us to perceiving rather complex impressions from simple sensory input. Bistable stimuli give us a rare opportunity to study the neural mechanisms behind this process. Such stimuli can be visually interpreted as simple or as more complex on the basis of the same sensory input. Previous studies demonstrated increased activity in the superior parietal cortex when participants perceived an illusory Gestalt impression compared to a simpler interpretation of individual elements. Here we tested whether activity related to the illusory Gestalt can be detected not only during, but also prior to it, by examining the slow fluctuations of resting-state-fMRI activity before the stimulus onset. We presented 31 participants with a bistable motion stimulus, which can be perceived either as four moving dot pairs (local) or two moving illusory squares (global). This allowed us to isolate the specific neural mechanisms that accompany the experience of an illusion under matched sensory input. fMRI was used to measure brain activity in a sparse event-related design. We observed stronger IPS and putamen responses to the stimulus when participants perceived the global interpretation compared to local, confirming the previously reported role of these areas in perceptual grouping. Most importantly, we also observed that the global stimulus interpretation was preceded by an increased activity of the bilateral dorsal insula, which is known to process saliency and gate information for conscious access. Our data suggest an important role of the dorsal insula in shaping an internally generated illusory Gestalt percept.

Modality and folk psychology

2019 ◽  
Vol 28 (1) ◽  
pp. 19-27
Author(s):  
Ja. O. Petik
Keyword(s):  
Modal Logic ◽  
Brain Activity ◽  
Formal System ◽  
Philosophy Of Logic ◽  
Psychological States ◽  
Formal Systems ◽  
Modern Psychology ◽  
Philosophical Interpretation ◽  
Important Direction

The connection of the modern psychology and formal systems remains an important direction of research. This paper is centered on philosophical problems surrounding relations between mental and logic. Main attention is given to philosophy of logic but certain ideas are introduced that can be incorporated into the practical philosophical logic. The definition and properties of basic modal logic and descending ones which are used in study of mental activity are in view. The defining role of philosophical interpretation of modality for the particular formal system used for research in the field of psychological states of agents is postulated. Different semantics of modal logic are studied. The hypothesis about the connection of research in cognitive psychology (semantics of brain activity) and formal systems connected to research of psychological states is stated.

Presence, Environment, and Sound and the Role of Imagination

2019 ◽  
pp. 667-681
Author(s):  
Mark Grimshaw-Aagaard
Keyword(s):  
Computer Games ◽  
Virtual World ◽  
Actual World ◽  
Sensory Input ◽  
The World ◽  
Visual Dimension ◽  
The Creation ◽  
First Person Shooter ◽  
Selection Of

Mark Grimshaw-Aagaard addresses the role of sound in the creation of presence in virtual and actual worlds. He argues that imagination is a central part of the generation and selection of perceptual hypotheses—models of the world in which we can act—that emerge from what Grimshaw-Aagaard calls the “exo-environment” (the sensory input) and the “endo-environment” (the cognitive input). Grimshaw-Aagaard further divides the exo-environment into a primarily auditory and a primarily visual dimension and he deals with the actual world of his own apartment and the virtual world of first-person-shooter computer games in order to exemplify how we perceptually construct an environment that allows for the creation of presence.

scholarly journals Delta band activity contributes to the identification of command following in disorder of consciousness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gonzalo Rivera-Lillo ◽  
Emmanuel A. Stamatakis ◽  
Tristan A. Bekinschtein ◽  
David K. Menon ◽  
Srivas Chennu
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Disorder Of Consciousness ◽  
Fine Grained ◽  
Electrical Brain Activity ◽  
Delta Band ◽  
Delta Modulation ◽  
Command Following ◽  
Band Activity

AbstractThe overt or covert ability to follow commands in patients with disorders of consciousness is considered a sign of awareness and has recently been defined as cortically mediated behaviour. Despite its clinical relevance, the brain signatures of the perceptual processing supporting command following have been elusive. This multimodal study investigates the temporal spectral pattern of electrical brain activity to identify features that differentiated healthy controls from patients both able and unable to follow commands. We combined evidence from behavioural assessment, functional neuroimaging during mental imagery and high-density electroencephalography collected during auditory prediction, from 21 patients and 10 controls. We used a penalised regression model to identify command following using features from electroencephalography. We identified seven well-defined spatiotemporal signatures in the delta, theta and alpha bands that together contribute to identify DoC subjects with and without the ability to follow command, and further distinguished these groups of patients from controls. A fine-grained analysis of these seven signatures enabled us to determine that increased delta modulation at the frontal sensors was the main feature in command following patients. In contrast, higher frequency theta and alpha modulations differentiated controls from both groups of patients. Our findings highlight a key role of spatiotemporally specific delta modulation in supporting cortically mediated behaviour including the ability to follow command. However, patients able to follow commands nevertheless have marked differences in brain activity in comparison with healthy volunteers.

scholarly journals Jumping over baselines with new methods to predict activation maps from resting-state fMRI

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eric Lacosse ◽  
Klaus Scheffler ◽  
Gabriele Lohmann ◽  
Georg Martius
Keyword(s):  
Resting State ◽  
Brain Activity ◽  
Resting State Fmri ◽  
Behavioral Differences ◽  
Large Variability ◽  
Single Vertex ◽  
Spontaneous Brain Activity ◽  
New Methods ◽  
Group Averaging ◽  
Proposed Modification

AbstractCognitive fMRI research primarily relies on task-averaged responses over many subjects to describe general principles of brain function. Nonetheless, there exists a large variability between subjects that is also reflected in spontaneous brain activity as measured by resting state fMRI (rsfMRI). Leveraging this fact, several recent studies have therefore aimed at predicting task activation from rsfMRI using various machine learning methods within a growing literature on ‘connectome fingerprinting’. In reviewing these results, we found lack of an evaluation against robust baselines that reliably supports a novelty of predictions for this task. On closer examination to reported methods, we found most underperform against trivial baseline model performances based on massive group averaging when whole-cortex prediction is considered. Here we present a modification to published methods that remedies this problem to large extent. Our proposed modification is based on a single-vertex approach that replaces commonly used brain parcellations. We further provide a summary of this model evaluation by characterizing empirical properties of where prediction for this task appears possible, explaining why some predictions largely fail for certain targets. Finally, with these empirical observations we investigate whether individual prediction scores explain individual behavioral differences in a task.

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