scholarly journals The SSVEP tool as a marker of subjective visibility

2019 ◽  
Author(s):  
Adélaïde de Heering ◽  
Arnaud Beauny ◽  
Laurène Vuillaume ◽  
Leila Salvesen ◽  
Axel Cleeremans
Keyword(s):  
Conscious Experience ◽  
Visual Images ◽  
Phenomenal Experience ◽  
Brain Response ◽  
Scalp Topography ◽  
The Face ◽  
Neural Signature ◽  
Face Stimuli ◽  
The Brain ◽  
Shed Light

ABSTRACTThis study is part of a larger attempt to explore how the brain produces conscious experience. Our main objective here was to take advantage of a neural signature conveyed by the steady-state visual evoked potentials (SSVEP) technique (1) to explore the extent to which complex visual images can be processed in the absence of consciousness and (2) to determine whether this tool can be used to shed light on participants’ phenomenal experience of these images. To this end, we embedded faces within sequences of non-face stimuli and manipulated their contrast to create a subliminal condition. Our results were threefold. First, we show that a significant brain activation can be delineated with the SSVEP tool even when participants report being unable to see the stimuli. In this subliminal condition, the brain response was confined to the back of the scalp. Second, we observe that the face signal increases in magnitude and propagates bilaterally along a posterior-to-anterior axis as image contrast increases. Third, we suggest that SSVEP could be used as a novel instance of a no-report paradigm because it requires no overt behavioural response, and because at some contrast levels and electrodes, its outputs (signal magnitude and scalp topography) predict people’s self-reported phenomenal experience.

scholarly journals Comparison between Daytime and Nighttime Scenery Focusing on Restorative and Recovery Effect

2019 ◽  
Vol 11 (12) ◽  
pp. 3326
Author(s):  
SangHyun Cheon ◽  
Soyoung Han ◽  
Mintai Kim ◽  
Yoonku Kwon
Keyword(s):  
Psychological Impact ◽  
Brain Regions ◽  
Visual Images ◽  
Built Environments ◽  
Brain Response ◽  
Reported Data ◽  
Physiological Variations ◽  
Negative Relationships ◽  
Electroencephalogram Eeg ◽  
The Brain

The overall purpose of this study was to investigate psycho-physiological variations in human bodies by observing visual images of daytime and nighttime scenery to focus on restorative and recovery effects. Unlike previous studies that have focused on the natural versus built environments, this study aims to compare restorative and recovery potentials between daytime and nighttime. The experiment was conducted by showing a total of 12 images to 60 participants in order to measure the brain response with an electroencephalogram (EEG). As measures of the psychological impact of the images, perceived restorative and recovery scales were used. The self-reported data indicates that daytime sceneries are rated more positively than nighttime sceneries in terms of restorative and recovery effects. According to the EEG results, restorative and recovery feelings have negative relationships with the relative theta band, while positive relationships are shown with the relative alpha band. The correlation analysis between EEG bands and brain regions showed a significant correlation (p < 0.05) with 46 pairs for the daytime scenery stimuli and 52 pairs for the nighttime scenery stimuli. Through the results of the study, we conclude that daytime and nighttime scenery affect restorative feelings and the human brain response through both verbal and non-verbal methods.

scholarly journals Functional Connectivity within and beyond the Face Network Is Related to Reduced Discrimination of Degraded Faces in Young and Older Adults

2020 ◽  
Vol 30 (12) ◽  
pp. 6206-6223
Author(s):  
Cheryl L Grady ◽  
Jenny R Rieck ◽  
Daniel Nichol ◽  
Douglas D Garrett
Keyword(s):  
Older Adults ◽  
Functional Connectivity ◽  
Brain Networks ◽  
Brain Network ◽  
Whole Brain ◽  
The Face ◽  
Brain Correlates ◽  
Brain And Behavior ◽  
Face Stimuli ◽  
The Brain

Abstract Degrading face stimuli reduces face discrimination in both young and older adults, but the brain correlates of this decline in performance are not fully understood. We used functional magnetic resonance imaging to examine the effects of degraded face stimuli on face and nonface brain networks and tested whether these changes would predict the linear declines seen in performance. We found decreased activity in the face network (FN) and a decrease in the similarity of functional connectivity (FC) in the FN across conditions as degradation increased but no effect of age. FC in whole-brain networks also changed with increasing degradation, including increasing FC between the visual network and cognitive control networks. Older adults showed reduced modulation of this whole-brain FC pattern. The strongest predictors of within-participant decline in accuracy were changes in whole-brain network FC and FC similarity of the FN. There was no influence of age on these brain-behavior relations. These results suggest that a systems-level approach beyond the FN is required to understand the brain correlates of performance decline when faces are obscured with noise. In addition, the association between brain and behavior changes was maintained into older age, despite the dampened FC response to face degradation seen in older adults.

Humility, Free Will Beliefs, and Existential Angst

2018 ◽  
Author(s):  
Thomas Nadelhoffer ◽  
Jennifer Cole Wright
Keyword(s):  
Free Will ◽  
Existential Anxiety ◽  
The Face ◽  
The Mind ◽  
The Relationship ◽  
The Brain ◽  
Shed Light

In Chapter 15, Thomas Nadelhoffer and Jennifer Cole Wright investigate the relationship between free will beliefs (or the lack thereof) and existential anxiety. In an attempt to shed light on this relationship, they set out to test whether trait humility can serve as a “buffer” between the two—that is, are people who are high in dispositional humility less likely to experience existential anxiety in the face of skepticism about free will? Given the perspectival and attitudinal nature of humility, Nadelhoffer and Wright predict that humble people will be less anxious in the face of stories about the purported death of free will (or the reduction of the mind to the brain). In a series of four studies, they test their hypothesis, with mixed results.,The findings, however, tell us something important about the current use of primes in studies designed to manipulate people’s belief in free will (usually to measure their pro- or antisocial effects).

scholarly journals Electrophysiological correlates of unconscious processes of race

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francesca Pesciarelli ◽  
Irene Leo ◽  
Luana Serafini
Keyword(s):  
Reaction Times ◽  
Event Related Potentials ◽  
Neural Mechanisms ◽  
Unconscious Processes ◽  
Race Effect ◽  
The Face ◽  
Related Potentials ◽  
Face Stimuli ◽  
The Brain ◽  
Prime Target

AbstractThe study aimed to examine the neural mechanisms underlying implicit other-race face processing by the use of the masked and unmasked priming manipulation. Two types of prime-target pairs were presented while recording Event-related potentials (ERPs): Same face pairs (prime-target were identical faces), and Different face pairs (prime-target were different faces). Prime-target pairs were half Asian (other-race) and half Caucasian (own-race) faces. The face stimuli on each pair were of the same gender and race. Participants (all Caucasians) had to decide whether the target was a male or a female face (gender task). The prime face could be unmasked or masked. On the behavioral side, our findings showed a race effect, that is slower reaction times (RTs) for other-race than own-race face stimuli, regardless of masking. On the ERPs side, our data showed a race effect across all components analyzed (P100, N100, N200, P300), under both the unmasked and masked manipulations. Besides, we found, in the unmasked condition, a priming effect as a function of race on the N100, N200, and P300 components; but, interestingly, in the masked condition, only on the P300. Overall, our findings provide evidence that race information is available very early in the brain and can strongly activate and influence people’s behaviors even without conscious awareness.

Turning the Face Inversion Effect on its Head: Violated Expectations of Orientation, Lighting and Gravity Enhance N170 Amplitudes.

2019 ◽  
Author(s):  
Yasmin Allen-Davidian ◽  
Manuela Russo ◽  
Naohide Yamamoto ◽  
Jordy Kaufman ◽  
Alan J. Pegna ◽  
...  
Keyword(s):  
Event Related Potential ◽  
N170 Amplitude ◽  
Face Inversion Effect ◽  
Face Inversion ◽  
Electrophysiological Responses ◽  
The Face ◽  
Face Stimuli ◽  
Violated Expectations ◽  
Processing Mechanisms ◽  
The Brain

Face Inversion Effects (FIEs) – differences in response to upside down faces compared to upright faces – occur for both behavioural and electrophysiological responses when people view face stimuli. In EEG, the inversion of a face is often reported to evoke an enhanced amplitude and delayed latency of the N170 event-related potential. This response has historically been attributed to the indexing of specialised face processing mechanisms within the brain. However, inspection of the literature revealed that while the N170 is consistently delayed to photographed, schematic, Mooney and line drawn face stimuli, only naturally photographed faces enhance the amplitude upon inversion. This raises the possibility that the increased N170 amplitudes to inverted faces may have other origins than the inversion of the face’s structural components. In line with previous research establishing the N170 as a prediction error signal, we hypothesise that the unique N170 amplitude response to inverted photographed faces stems from multiple expectation violations, over and above structural inversion. For instance, rotating an image of a face upside down not only violates the expectation that faces appear upright, but also lifelong priors that illumination comes from above and gravity pulls from below. To test this hypothesis, we recorded EEG whilst participants viewed face stimuli (upright versus inverted), where the faces were illuminated from above versus below, and where the models were photographed upright versus hanging upside down. The N170 amplitudes were found to be modulated by a complex interaction between orientation, lighting and gravity factors, with the amplitudes largest when faces consistently violated all three expectations and smallest when all these factors concurred with expectations. These results confirm our hypothesis that FIEs on N170 amplitudes are driven by a violation of the viewer’s expectations across several parameters that characterise faces, rather than a disruption in the configurational disposition of its features.

scholarly journals Turning the Face Inversion Effect on Its Head: Violated Expectations of Orientation, Lighting, and Gravity Enhance N170 Amplitudes

2021 ◽  
Vol 33 (2) ◽  
pp. 303-314
Author(s):  
Yasmin Allen-Davidian ◽  
Manuela Russo ◽  
Naohide Yamamoto ◽  
Jordy Kaufman ◽  
Alan J. Pegna ◽  
...  
Keyword(s):  
N170 Amplitude ◽  
Face Inversion Effect ◽  
Face Inversion ◽  
Electrophysiological Responses ◽  
The Face ◽  
Face Stimuli ◽  
Violated Expectations ◽  
Processing Mechanisms ◽  
The Brain ◽  
Inversion Effects

Face inversion effects occur for both behavioral and electrophysiological responses when people view faces. In EEG, inverted faces are often reported to evoke an enhanced amplitude and delayed latency of the N170 ERP. This response has been attributed to the indexing of specialized face processing mechanisms within the brain. However, inspection of the literature revealed that, although N170 is consistently delayed to a variety of face representations, only photographed faces invoke enhanced N170 amplitudes upon inversion. This suggests that the increased N170 amplitudes to inverted faces may have other origins than the inversion of the face's structure. We hypothesize that the unique N170 amplitude response to inverted photographed faces stems from multiple expectation violations, over and above structural inversion. For instance, rotating an image of a face upside–down not only violates the expectation that faces appear upright but also lifelong priors about illumination and gravity. We recorded EEG while participants viewed face stimuli (upright vs. inverted), where the faces were illuminated from above versus below, and where the models were photographed upright versus hanging upside–down. The N170 amplitudes were found to be modulated by a complex interaction between orientation, lighting, and gravity factors, with the amplitudes largest when faces consistently violated all three expectations. These results confirm our hypothesis that face inversion effects on N170 amplitudes are driven by a violation of the viewer's expectations across several parameters that characterize faces, rather than a disruption in the configurational disposition of its features.

scholarly journals Decoding the auditory brain with canonical component analysis

2017 ◽  
Author(s):  
Alain de Cheveigné ◽  
Daniel Wong ◽  
Giovanni M. Di Liberto ◽  
Jens Hjortkjaer ◽  
Malcolm Slaney ◽  
...  
Keyword(s):  
Event Related Potential ◽  
Computer Interface ◽  
Brain Response ◽  
Response Mapping ◽  
Stimulus Response ◽  
Stimulus Representation ◽  
Brain Signals ◽  
Increased Sensitivity ◽  
The Brain ◽  
Shed Light

AbstractThe relation between a stimulus and the evoked brain response can shed light on perceptual processes within the brain. Signals derived from this relation can also be harnessed to control external devices for Brain Computer Interface (BCI) appli-cations. While the classic event-related potential (ERP) is appropriate for isolated stimuli, more sophisticated “decoding” strategies are needed to address continuous stimuli such as speech, music or environmental sounds. Here we describe an approach based on Canonical Correlation Analysis (CCA) that finds the optimal transform to apply to both the stimulus and the response to reveal correlations between the two. Compared to prior methods based on forward or backward models for stimulus-response mapping, CCA finds significantly higher correlation scores, thus providing increased sensitivity to relatively small effects, and supports classifier schemes that yield higher classification scores. CCA strips the brain response of variance unrelated to the stimulus, and the stimulus representation of variance that does not affect the response, and thus improves observations of the relation between stimulus and response.

About the Brain, the Face, and Emotion

1984 ◽  
Vol 29 (7) ◽  
pp. 567-568
Author(s):  
Gilles Kirouac
Keyword(s):  
The Face ◽  
The Brain

Consciousness

2018 ◽  
Author(s):  
Anil K. Seth
Keyword(s):  
Conscious Experience ◽  
Real Problem ◽  
Active Inference ◽  
Biological Mechanisms ◽  
Specific Content ◽  
Brain Responses ◽  
Biomimetic Approach ◽  
Multiple Levels ◽  
In Virtue Of ◽  
The Brain

Consciousness is perhaps the most familiar aspect of our existence, yet we still do not know its biological basis. This chapter outlines a biomimetic approach to consciousness science, identifying three principles linking properties of conscious experience to potential biological mechanisms. First, conscious experiences generate large quantities of information in virtue of being simultaneously integrated and differentiated. Second, the brain continuously generates predictions about the world and self, which account for the specific content of conscious scenes. Third, the conscious self depends on active inference of self-related signals at multiple levels. Research following these principles helps move from establishing correlations between brain responses and consciousness towards explanations which account for phenomenological properties—addressing what can be called the “real problem” of consciousness. The picture that emerges is one in which consciousness, mind, and life, are tightly bound together—with implications for any possible future “conscious machines.”

scholarly journals Time to Be SHY? Some Comments on Sleep and Synaptic Homeostasis

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Giulio Tononi ◽  
Chiara Cirelli
Keyword(s):  
Synaptic Strength ◽  
Universal Function ◽  
Systematic Bias ◽  
Synaptic Homeostasis ◽  
The Face ◽  
Essential Function ◽  
Function Of Sleep ◽  
The Brain

Sleep must serve an essential, universal function, one that offsets the risk of being disconnected from the environment. The synaptic homeostasis hypothesis (SHY) is an attempt to identify this essential function. Its core claim is that sleep is needed to reestablish synaptic homeostasis, which is challenged by the remarkable plasticity of the brain. In other words, sleep is “the price we pay for plasticity.” In this issue, M. G. Frank reviewed several aspects of the hypothesis and raised several issues. The comments below provide a brief summary of the motivations underlying SHY and clarify that SHY is a hypothesis not about specific mechanisms, but about a universal, essential function of sleep. This function is the preservation of synaptic homeostasis in the face of a systematic bias toward a net increase in synaptic strength—a challenge that is posed by learning during adult wake, and by massive synaptogenesis during development.

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