Probing Electrophysiological Indices of Perceptual Awareness across Unisensory and Multisensory Modalities

2018 ◽  
Vol 30 (6) ◽  
pp. 814-828 ◽  
Author(s):  
Jean-Paul Noel ◽  
David Simon ◽  
Antonia Thelen ◽  
Alexander Maier ◽  
Randolph Blake ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Multisensory Processing ◽  
Neural Correlates ◽  
Perceptual Awareness ◽  
Neural Signals ◽  
Neural Architecture ◽  
Brain Responses ◽  
Sensory Modalities ◽  
Audiovisual Stimuli ◽  
Neural Underpinnings

The neural underpinnings of perceptual awareness have been extensively studied using unisensory (e.g., visual alone) stimuli. However, perception is generally multisensory, and it is unclear whether the neural architecture uncovered in these studies directly translates to the multisensory domain. Here, we use EEG to examine brain responses associated with the processing of visual, auditory, and audiovisual stimuli presented near threshold levels of detectability, with the aim of deciphering similarities and differences in the neural signals indexing the transition into perceptual awareness across vision, audition, and combined visual–auditory (multisensory) processing. More specifically, we examine (1) the presence of late evoked potentials (∼>300 msec), (2) the across-trial reproducibility, and (3) the evoked complexity associated with perceived versus nonperceived stimuli. Results reveal that, although perceived stimuli are associated with the presence of late evoked potentials across each of the examined sensory modalities, between-trial variability and EEG complexity differed for unisensory versus multisensory conditions. Whereas across-trial variability and complexity differed for perceived versus nonperceived stimuli in the visual and auditory conditions, this was not the case for the multisensory condition. Taken together, these results suggest that there are fundamental differences in the neural correlates of perceptual awareness for unisensory versus multisensory stimuli. Specifically, the work argues that the presence of late evoked potentials, as opposed to neural reproducibility or complexity, most closely tracks perceptual awareness regardless of the nature of the sensory stimulus. In addition, the current findings suggest a greater similarity between the neural correlates of perceptual awareness of unisensory (visual and auditory) stimuli when compared with multisensory stimuli.

scholarly journals Associative learning and extinction of conditioned threat predictors across sensory modalities

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Laura. R. Koenen ◽  
Robert. J. Pawlik ◽  
Adriane Icenhour ◽  
Ljubov Petrakova ◽  
Katarina Forkmann ◽  
...  
Keyword(s):  
Visceral Pain ◽  
Neural Correlates ◽  
Imaging Studies ◽  
Somatic Pain ◽  
Healthy Humans ◽  
Sensory Modalities ◽  
The Face ◽  
Nocebo Effects ◽  
Conditioned Responses ◽  
Clinical Conditions

AbstractThe formation and persistence of negative pain-related expectations by classical conditioning remain incompletely understood. We elucidated behavioural and neural correlates involved in the acquisition and extinction of negative expectations towards different threats across sensory modalities. In two complementary functional magnetic resonance imaging studies in healthy humans, differential conditioning paradigms combined interoceptive visceral pain with somatic pain (study 1) and aversive tone (study 2) as exteroceptive threats. Conditioned responses to interoceptive threat predictors were enhanced in both studies, consistently involving the insula and cingulate cortex. Interoceptive threats had a greater impact on extinction efficacy, resulting in disruption of ongoing extinction (study 1), and selective resurgence of interoceptive CS-US associations after complete extinction (study 2). In the face of multiple threats, we preferentially learn, store, and remember interoceptive danger signals. As key mediators of nocebo effects, conditioned responses may be particularly relevant to clinical conditions involving disturbed interoception and chronic visceral pain.

Don't tell anyone: the importance of no-report paradigms in neuroscience of consciousness

2021 ◽  
Author(s):  
Maria Del Vecchio
Keyword(s):  
Neural Correlates ◽  
Neural Responses ◽  
Perceptual Awareness ◽  
Experimental Conditions ◽  
Conscious Processing

The neural correlates of perceptual awareness are usually investigated by comparing experimental conditions in which subjects are aware or not aware of the delivered stimulus. This, however implies that subjects report their experience, possibly biasing the neural responses with the post-perceptual processes involved. This Neuro Forum article reviews evidence from an electroencephalography (EEG) study by Cohen and colleagues (Cohen M. et al. Journal of Neuroscience 40 (25) 4925-4935) addressing the importance of no-report paradigms in the neuroscience of consciousness. In particular, authors shows of P3b, one of the proposed canonical "signatures" of the conscious processing, is strongly elicited only when subjects have to report their experience, proposing a reconsideration in the approach to the neuroscience of consciousness.

scholarly journals Conceptual Priming and Familiarity: Different Expressions of Memory during Recognition Testing with Distinct Neurophysiological Correlates

2010 ◽  
Vol 22 (11) ◽  
pp. 2638-2651 ◽  
Author(s):  
Joel L. Voss ◽  
Heather D. Lucas ◽  
Ken A. Paller
Keyword(s):  
Implicit Memory ◽  
Explicit Memory ◽  
Neural Correlates ◽  
Neural Responses ◽  
Neural Signals ◽  
Conceptual Information ◽  
Conceptual Priming ◽  
Familiarity And Recollection ◽  
Recognition Testing ◽  
Different Characteristics

Familiarity and recollection are qualitatively different explicit-memory phenomena evident during recognition testing. Investigations of the neurocognitive substrates of familiarity and recollection, however, have typically disregarded implicit-memory processes likely to be engaged during recognition tests. We reasoned that differential neural responses to old and new items in a recognition test may reflect either explicit or implicit memory. Putative neural correlates of familiarity in prior experiments, for example, may actually reflect contamination by implicit memory. In two experiments, we used obscure words that subjects could not formally define to tease apart electrophysiological correlates of familiarity and one form of implicit memory, conceptual priming. In Experiment 1, conceptual priming was observed for words only if they elicited meaningful associations. In Experiment 2, two distinct neural signals were observed in conjunction with familiarity-based recognition: late posterior potentials for words that both did and did not elicit meaningful associations and FN400 potentials only for the former. Given that symbolic meaning is a prerequisite for conceptual priming, the combined results specifically link late posterior potentials and FN400 potentials with familiarity and conceptual priming, respectively. These findings contradict previous interpretations of FN400 potentials as generic signals of familiarity and show that repeated stimuli in recognition tests can engender facilitated processing of conceptual information in addition to retrieval processing that leads to the awareness of memory retrieval. The different characteristics of the electrical markers of these two types of process further underscore the biological validity of the distinction between implicit memory and explicit memory.

scholarly journals Application of Referencing Techniques in EEG-Based Recordings of Contact Heat Evoked Potentials (CHEPS)

2020 ◽  
Vol 14 ◽  
Author(s):  
Malte Anders ◽  
Björn Anders ◽  
Matthias Kreuzer ◽  
Sebastian Zinn ◽  
Carmen Walter
Keyword(s):  
Evoked Potentials ◽  
Reference Electrode ◽  
Objective Measure ◽  
Time Spectrum ◽  
Electrode Site ◽  
Contact Heat ◽  
Theoretical Terms ◽  
Average Reference ◽  
Brain Responses ◽  
Contact Heat Evoked Potentials

Evoked potentials in the amplitude-time spectrum of the electroencephalogram are commonly used to assess the extent of brain responses to stimulation with noxious contact heat. The magnitude of the N- and P-waves are used as a semi-objective measure of the response to the painful stimulus: the higher the magnitude, the more painful the stimulus has been perceived. The strength of the N-P-wave response is also largely dependent on the chosen reference electrode site. The goal of this study was to examine which reference technique excels both in practical and theoretical terms when analyzing noxious contact heat evoked potentials (CHEPS) in the amplitude-time spectrum. We recruited 21 subjects (10 male, 11 female, mean age of 55.79 years). We applied seven noxious contact heat stimuli using two temperatures, 51°C, and 54°C, to each subject. During EEG analysis, we aimed to identify the referencing technique which produces the highest N-wave and P-wave amplitudes with as little artifactual influence as possible. For this purpose, we applied the following six referencing techniques: mathematically linked A1/A2 (earlobes), average reference, REST, AFz, Pz, and mathematically linked PO7/PO8. We evaluated how these techniques impact the N-P amplitudes of CHEPS based on our data from healthy subjects. Considering all factors, we found that mathematically linked earlobes to be the ideal referencing site to use when displaying and evaluating CHEPS in the amplitude-time spectrum.

Testing domain-general theories of perceptual awareness with auditory brain responses

2015 ◽  
Vol 19 (6) ◽  
pp. 295-297 ◽  
Author(s):  
Joel S. Snyder ◽  
Breanne D. Yerkes ◽  
Michael A. Pitts
Keyword(s):  
Perceptual Awareness ◽  
Brain Responses

scholarly journals Physiological Correlates of Sensory Consciousness: Evidence for a Generalized Awareness Negativity

2021 ◽  
Author(s):  
Cole Dembski ◽  
Christof Koch ◽  
Michael Pitts
Keyword(s):  
Experimental Studies ◽  
Neural Correlates ◽  
Stimulus Onset ◽  
Convincing Evidence ◽  
Future Research ◽  
Neural Signals ◽  
Tactile Stimuli ◽  
Neurological Patients ◽  
Sensory Cortices ◽  
Sensory Consciousness

We critically review the recent literature on six EEG and MEG markers of the neural correlates of consciousness (NCC) for visual, auditory and tactile stimuli in neurotypical volunteers and neurological patients. After ruling out four of these as candidate NCC, we focus on two prominent evoked signals: an early, modality-specific negativity, termed the visual or auditory awareness negativity (VAN and AAN, respectively) and a late, modality-independent positivity termed the P3b. More than twelve diverse experimental studies found that the P3b is absent despite consciously seeing, hearing, or feeling stimuli, ruling out the P3b as a true NCC. In contrast, no convincing evidence for a dissociation between the awareness negativities and consciousness has been reported thus far. Furthermore, there is evidence for an equivalent signal in the tactile domain, which we term the somatosensory awareness negativity (SAN). These three neural signals are usually maximal on the side of the scalp contralateral to the evoking stimulus, above the associated sensory cortices. We conclude that the data from these three modalities is consistent with a generalized awareness negativity (GAN) correlated with perceptual consciousness that arises 120-200 ms following stimulus onset and originates from the underlying sensory cortices. The identification of this GAN points towards new, promising avenues for future research and raises an array of concrete questions that can be empirically investigated.

Sign in / Sign up

Export Citation Format

Share Document