scholarly journals Should a few null findings falsify prefrontal theories of conscious perception?

2017 ◽  
Author(s):  
Brian Odegaard ◽  
Robert T. Knight ◽  
Hakwan Lau
Keyword(s):  
Essential Role ◽  
Subjective Experience ◽  
Perceptual Content ◽  
Subjective Perception ◽  
Conscious Perception ◽  
Perceptual Awareness ◽  
Visual Tasks ◽  
Common Misconceptions ◽  
Limited Sensitivity

AbstractIs activity in prefrontal cortex (PFC) critical for conscious perception? Major theories of consciousness make distinct predictions about the role of PFC, providing an opportunity to arbitrate between these views empirically. Here we address three common misconceptions: i) PFC lesions do not affect subjective perception; ii) PFC activity does not reflect specific perceptual content; iii) PFC involvement in studies of perceptual awareness is solely driven by the need to make reports required by the experimental tasks, rather than subjective experience per se. These claims are incompatible with empirical findings, unless one focuses only on studies using methods with limited sensitivity. The literature highlights PFC’s essential role in enabling the subjective experience in perception, contra the objective capacity to perform visual tasks; conflating the two can also be a source of confusion.

scholarly journals Subjective visual perception: from local processing to emergent phenomena of brain activity

2014 ◽  
Vol 369 (1641) ◽  
pp. 20130534 ◽  
Author(s):  
Theofanis I. Panagiotaropoulos ◽  
Vishal Kapoor ◽  
Nikos K. Logothetis
Keyword(s):  
Visual Perception ◽  
Visual Stimulation ◽  
Brain Activity ◽  
Sensory Information ◽  
Brain Regions ◽  
Intrinsic Activity ◽  
Subjective Perception ◽  
Conscious Perception ◽  
Perceptual Awareness ◽  
Sensory Stimuli

The combination of electrophysiological recordings with ambiguous visual stimulation made possible the detection of neurons that represent the content of subjective visual perception and perceptual suppression in multiple cortical and subcortical brain regions. These neuronal populations, commonly referred to as the neural correlates of consciousness , are more likely to be found in the temporal and prefrontal cortices as well as the pulvinar, indicating that the content of perceptual awareness is represented with higher fidelity in higher-order association areas of the cortical and thalamic hierarchy, reflecting the outcome of competitive interactions between conflicting sensory information resolved in earlier stages. However, despite the significant insights into conscious perception gained through monitoring the activities of single neurons and small, local populations, the immense functional complexity of the brain arising from correlations in the activity of its constituent parts suggests that local, microscopic activity could only partially reveal the mechanisms involved in perceptual awareness. Rather, the dynamics of functional connectivity patterns on a mesoscopic and macroscopic level could be critical for conscious perception. Understanding these emergent spatio-temporal patterns could be informative not only for the stability of subjective perception but also for spontaneous perceptual transitions suggested to depend either on the dynamics of antagonistic ensembles or on global intrinsic activity fluctuations that may act upon explicit neural representations of sensory stimuli and induce perceptual reorganization. Here, we review the most recent results from local activity recordings and discuss the potential role of effective, correlated interactions during perceptual awareness.

The Role of Distress Disclosure Tendencies in the Experience and Expression of Laboratory-Induced Sadness

2017 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Jeffrey H. Kahn ◽  
Daniel W. Cox ◽  
A. Myfanwy Bakker ◽  
Julia I. O’Loughlin ◽  
Agnieszka M. Kotlarczyk
Keyword(s):  
Individual Differences ◽  
Emotional Reactivity ◽  
Subjective Experience ◽  
Negative Emotion ◽  
Theoretical Models ◽  
Laboratory Research ◽  
Emotion Words ◽  
Distress Disclosure ◽  
Computerized Text Analysis

Abstract. The benefits of talking with others about unpleasant emotions have been thoroughly investigated, but individual differences in distress disclosure tendencies have not been adequately integrated within theoretical models of emotion. The purpose of this laboratory research was to determine whether distress disclosure tendencies stem from differences in emotional reactivity or differences in emotion regulation. After completing measures of distress disclosure tendencies, social desirability, and positive and negative affect, 84 participants (74% women) were video recorded while viewing a sadness-inducing film clip. Participants completed post-film measures of affect and were then interviewed about their reactions to the film; these interviews were audio recorded for later coding and computerized text analysis. Distress disclosure tendencies were not predictive of the subjective experience of emotion, but they were positively related to facial expressions of sadness and happiness. Distress disclosure tendencies also predicted judges’ ratings of the verbal disclosure of emotion during the interview, but self-reported disclosure and use of positive and negative emotion words were not associated with distress disclosure tendencies. The authors present implications of this research for integrating individual differences in distress disclosure with models of emotion.

Essential role of Sharpin in TNFα dependent NFκB activation in primary hepatocytes

2012 ◽  
Vol 50 (01) ◽  
Author(s):  
N Lange ◽  
S Sieber ◽  
A Erhardt ◽  
G Sass ◽  
HJ Kreienkamp ◽  
...  
Keyword(s):  
Essential Role ◽  
Primary Hepatocytes

Different Abilities of Thrombin Receptor Activating Peptide and Thrombin to Induce Platelet Calcium Rise and Full Release Reaction

1995 ◽  
Vol 74 (05) ◽  
pp. 1323-1328 ◽  
Author(s):  
Dominique Lasne ◽  
José Donato ◽  
Hervé Falet ◽  
Francine Rendu
Keyword(s):  
Essential Role ◽  
Calcium Influx ◽  
Dense Granule ◽  
Receptor Interaction ◽  
Thrombin Receptor ◽  
Release Reaction ◽  
External Calcium ◽  
Maximum Rise ◽  
Granule Release

SummarySynthetic peptides (TRAP or Thrombin Receptor Activating Peptide) corresponding to at least the first five aminoacids of the new N-terminal tail generated after thrombin proteolysis of its receptor are effective to mimic thrombin. We have studied two different TRAPs (SFLLR, and SFLLRN) in their effectiveness to induce the different platelet responses in comparison with thrombin. Using Indo-1/AM- labelled platelets, the maximum rise in cytoplasmic ionized calcium was lower with TRAPs than with thrombin. At threshold concentrations allowing maximal aggregation (50 μM SFLLR, 5 μM SFLLRN and 1 nM thrombin) the TRAPs-induced release reaction was about the same level as with thrombin, except when external calcium was removed by addition of 1 mM EDTA. In these conditions, the dense granule release induced by TRAPs was reduced by over 60%, that of lysosome release by 75%, compared to only 15% of reduction in the presence of thrombin. Thus calcium influx was more important for TRAPs-induced release than for thrombin-induced release. At strong concentrations giving maximal aggregation and release in the absence of secondary mediators (by pretreatment with ADP scavengers plus aspirin), SFLLRN mobilized less calcium, with a fast return towards the basal level and induced smaller lysosome release than did thrombin. The results further demonstrate the essential role of external calcium in triggering sustained and full platelet responses, and emphasize the major difference between TRAP and thrombin in mobilizing [Ca2+]j. Thus, apart from the proteolysis of the seven transmembrane receptor, another thrombin binding site or thrombin receptor interaction is required to obtain full and complete responses.

Collagen-Induced Platelet Aggregation: -Evidence Against the Essential Role of Platelet Adenosine Diphosphate

1979 ◽  
Vol 42 (04) ◽  
pp. 1193-1206 ◽  
Author(s):  
Barbara Nunn
Keyword(s):  
Platelet Aggregation ◽  
Time Course ◽  
Essential Role ◽  
Atp Release ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
High Doses ◽  
Induced Aggregation

SummaryThe hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 μM ADP, were not inhibited by 500 pM adenosine, a concentration that greatly reduced the effect of 300 μM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.

Le premier moment de l’art dans À la recherche du temps perdu de Marcel Proust – une « leçon d’idéalisme » ?

2020 ◽  
pp. 25-40
Author(s):  
Larisa Botnari
Keyword(s):  
Essential Role ◽  
Marcel Proust ◽  
The Self ◽  
Philosophy Of Art ◽  
The Novel ◽  
Philosophical Interpretation ◽  
German Philosopher ◽  
Lost Time ◽  
Aesthetic Thinking

Although very famous, some key moments of the novel In Search of Lost Time, such as those of the madeleine or the uneven pavement, often remain enigmatic for the reader. Our article attempts to formulate a possible philosophical interpretation of the narrator's experiences during these scenes, through a confrontation of the Proustian text with the ideas found in the System of Transcendental Idealism (1800) of the German philosopher F. W. J. Schelling. We thus try to highlight the essential role of the self in Marcel Proust's aesthetic thinking, by showing that the mysterious happiness felt by the narrator, and from which the project of creating a work of art is ultimately born, is similar to the experiences of pure self-consciousness evoked and analyzed by Schellingian philosophy of art.

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