scholarly journals A structural constraint on neural correlates of consciousness

2021 ◽  
Vol 2 ◽  
Author(s):  
Sascha Benjamin Fink ◽  
Holger Lyre ◽  
Lukas Kob

Researchers on the neural correlates of consciousness (NCC) need to distinguish mere statisticalNCCs from NCCs proper. Some neural events may be co-occurrent, probabilistically coupled,or coincidental with a type of conscious experience but lack any deeper connection to it, whilein other cases, the relation between neural states and a type of experience hints at a strongmetaphysical relation, which distinguishes such NCCs proper from mere statistical NCCs. In orderto address this issue of how to distinguish NCCs proper from mere statistical NCCs, we proposea position we call neurophenomenal structuralism. The position hinges on the uncontroversialidea that phenomenal experiences relate to each other in degrees of similarity and difference.These complex structures are used to identify and individuate experiences in the methods ofneuroscience, psychophysics, and phenomenology. Such individuation by structure leads to phenomenalholism, which has implications for how to investigate consciousness neuroscientificallyand generates a constraint by which we can distinguish NCCs proper from mere statistical NCCs:the structural similarity constraint. Neural activation must preserve the structure governing thedomain of experiences it is associated with in order to count as that domain’s NCC proper. Anyactivation that fails to preserve phenomenal structure fails to be an NCC proper. We illustratehow this constraint works with a study by Brouwer & Heeger (2009) as an example.

2021 ◽  
Vol 2 ◽  
Author(s):  
Morten S. Overgaard ◽  
Asger Kirkeby-Hinrup

Subjective experience has often taken center stage in debates between competing conceptual theories of the mind. This is also a central object of concern in the empirical domain, and especially in the search for the neural correlates of consciousness (NCCs). By now, most of the competing conceptual theories of consciousness have become aligned with distinct hypotheses about the NCCs. These hypotheses are usually distinguished by reference to their proposed location of the NCCs. This difference in hypothesized location of the NCCs has tempted participants in these debates to infer that evidence indicating the location of the NCCs in one or the other brain region can be taken as direct evidence for or against a given conceptual theory of consciousness. We argue that this is an overestimation of the work finding the NCCs can do for us, and that there are principled reasons to resist this kind of inference. To show this we point out the lack of both an isomorphism and a homomorphism between the conceptual frameworks in which most theories are cached, and the kind of data we can get from neuroimaging. The upshot is that neural activation profiles are insufficient to distinguish between competing theories in the conceptual domain. We suggest two ways to go about ameliorating this issue.


2014 ◽  
Vol 369 (1641) ◽  
pp. 20130211 ◽  
Author(s):  
Randolph Blake ◽  
Jan Brascamp ◽  
David J. Heeger

This essay critically examines the extent to which binocular rivalry can provide important clues about the neural correlates of conscious visual perception. Our ideas are presented within the framework of four questions about the use of rivalry for this purpose: (i) what constitutes an adequate comparison condition for gauging rivalry's impact on awareness, (ii) how can one distinguish abolished awareness from inattention, (iii) when one obtains unequivocal evidence for a causal link between a fluctuating measure of neural activity and fluctuating perceptual states during rivalry, will it generalize to other stimulus conditions and perceptual phenomena and (iv) does such evidence necessarily indicate that this neural activity constitutes a neural correlate of consciousness? While arriving at sceptical answers to these four questions, the essay nonetheless offers some ideas about how a more nuanced utilization of binocular rivalry may still provide fundamental insights about neural dynamics, and glimpses of at least some of the ingredients comprising neural correlates of consciousness, including those involved in perceptual decision-making.


Author(s):  
Ali Motavalli ◽  
◽  
Javad Mahmoudi ◽  
Alireza Majdi ◽  
Saeed Sadigh-Eteghad ◽  
...  

Although there are numerous views about the concept of consciousness, no consensus exists regarding the meaning. However, with the aid of the latest neuroscientific developments, the misleading obstacles related to consciousness have been removed. Over the last few decades, neuroscientific efforts in determining the function of the brain and merging these findings with philosophical theories, have brought a more comprehensive perception of the notion of consciousness. In addition to metaphysical/ontological views of consciousness e.g., higher-order theories, reflexive theories, and representationalist theories, there are some brain directed topics in this matter which include but not are limited to neural correlates of consciousness (NCC), brain loop connectivity, and lateralization. This narrative review sheds light on cultural and historical aspects of consciousness in old and middle ages and introduces some of the prominent philosophical discussions related to mind and body. Also, it illustrates the correlation of brain function with states of consciousness with a focus on the roles of function and connectivity.


2018 ◽  
Vol 14 ◽  
pp. 747-755 ◽  
Author(s):  
Márton Bojtár ◽  
Péter Zoltán Janzsó-Berend ◽  
Dávid Mester ◽  
Dóra Hessz ◽  
Mihály Kállay ◽  
...  

Background: Nucleotides are essential molecules in living systems due to their paramount importance in various physiological processes. In the past years, numerous attempts were made to selectively recognize and detect these analytes, especially ATP using small-molecule fluorescent chemosensors. Despite the various solutions, the selective detection of ATP is still challenging due to the structural similarity of various nucleotides. In this paper, we report the conjugation of a uracil nucleobase to the known 4’-dimethylamino-hydroxyflavone fluorophore. Results: The complexation of this scaffold with ATP is already known. The complex is held together by stacking and electrostatic interactions. To achieve multi-point recognition, we designed the uracil-appended version of this probe to include complementary base-pairing interactions. The theoretical calculations revealed the availability of multiple complex structures. The synthesis was performed using click chemistry and the nucleotide recognition properties of the probe were evaluated using fluorescence spectroscopy. Conclusions: The first, uracil-containing fluorescent ATP probe based on a hydroxyflavone fluorophore was synthesized and evaluated. A selective complexation with ATP was observed and a ratiometric response in the excitation spectrum.


2021 ◽  
Vol 15 ◽  
Author(s):  
Jesse J. Winters

In recent years, there has been a proliferation of neuroscientific theories of consciousness. These include theories which explicitly point to EM fields, notably Operational Architectonics and, more recently, the General Resonance Theory. In phenomenological terms, human consciousness is a unified composition of contents. These contents are specific and meaningful, and they exist from a subjective point of view. Human conscious experience is temporally continuous, limited in content, and coherent. Based upon those phenomenal observations, pre-existing theories of consciousness, and a large body of experimental evidence, I derived the Temporally-Integrated Causality Landscape (TICL). In brief, the TICL proposes that the neural correlate of consciousness is a structure of temporally integrated causality occurring over a large portion of the thalamocortical system. This structure is composed of a large, integrated set of neuronal elements (the System), which contains some subsystems, defined as having a higher level of temporally-integrated causality than the System as a whole. Each Subsystem exists from the point of view of the System, in the form of meaningful content. In this article, I review the TICL and consider the importance of EM forces as a mechanism of neural causality. I compare the fundamentals of TICL to those of several other neuroscientific theories. Using five major characteristics of phenomenal consciousness as a standard, I compare the basic tenets of Integrated Information Theory, Global Neuronal Workspace, General Resonance Theory, Operational Architectonics, and the Temporo-spatial Theory of Consciousness with the framework of the TICL. While the literature concerned with these theories tends to focus on different lines of evidence, there are fundamental areas of agreement. This means that, in time, it may be possible for many of them to converge upon the truth. In this analysis, I conclude that a primary distinction which divides these theories is the feature of spatial and temporal nesting. Interestingly, this distinction does not separate along the fault line between theories explicitly concerned with EM fields and those which are not. I believe that reconciliation is possible, at least in principle, among those theories that recognize the following: just as the contents of consciousness are distinctions within consciousness, the neural correlates of conscious content should be distinguishable from but fall within the spatial and temporal boundaries of the full neural correlates of consciousness.


Cortex ◽  
2019 ◽  
Vol 120 ◽  
pp. 539-555
Author(s):  
María Hernández-Lorca ◽  
Kristian Sandberg ◽  
Dominique Kessel ◽  
Uxía Fernández-Folgueiras ◽  
Morten Overgaard ◽  
...  

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