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  1. Article: The Nature of Illusions: A New Synthesis Based on Verifiability.

    Tyler, Christopher W

    Frontiers in human neuroscience

    2022  Volume 16, Page(s) 875829

    Abstract: This overview discusses the nature of perceptual illusions with particular reference to the theory that illusions represent the operation of a sensory code for which there is no meaningful ground truth against which the illusory percepts can be compared, ...

    Abstract This overview discusses the nature of perceptual illusions with particular reference to the theory that illusions represent the operation of a sensory code for which there is no meaningful ground truth against which the illusory percepts can be compared, and therefore there are no illusions as such. This view corresponds to the Bayesian theory that "illusions" reflect unusual aspects of the core strategies of adapting to the natural world, again implying that illusions are simply an information processing characteristic. Instead, it is argued that a more meaningful approach to the field that we call illusions is the Ebbinghaus approach of comparing the illusory percept with a ground truth that is directly verifiable as aberrant by the observer in the domain of the illusory phenomenology (as opposed to relying on the authority of other experts). This concept of direct verifiability not only provides an operational definition of "illusion"; it also makes their interactive observation more effective and informative as to the perceptual processes underlying the illusory appearance. An expanded version of Gregory's categorization of types of illusion is developed, and a range of classic and more recent illusions that illustrate the differences between these philosophical viewpoints is considered in detail. Such cases make it clear that the discrepancies from the measurable image structure cannot be simply regarded as idiosyncrasies of sensory coding, but are categorical exemplars of perceptual illusions. The widespread existence of such illusory percepts is indicative of the evolutionary limits of adaptive sensory coding.
    Language English
    Publishing date 2022-05-31
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2425477-0
    ISSN 1662-5161
    ISSN 1662-5161
    DOI 10.3389/fnhum.2022.875829
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online: Neural Signal Estimation in the Human Brain

    Howarth, Clare / Tyler, Christopher W. / Likova, Lora T.

    2016  

    Abstract: The ultimate goal of functional brain imaging is to provide optimal estimates of the neural signals flowing through the long-range and local pathways mediating all behavioral performance and conscious experience. In functional MRI (Magnetic Resonance ... ...

    Abstract The ultimate goal of functional brain imaging is to provide optimal estimates of the neural signals flowing through the long-range and local pathways mediating all behavioral performance and conscious experience. In functional MRI (Magnetic Resonance Imaging), despite its impressive spatial resolution, this goal has been somewhat undermined by the fact that the fMRI response is essentially a blood-oxygenation level dependent (BOLD) signal that only indirectly reflects the nearby neural activity. The vast majority of fMRI studies restrict themselves to describing the details of these BOLD signals and deriving non-quantitative inferences about their implications for the underlying neural activity. This Frontiers Research Topic welcomed empirical and theoretical contributions that focus on the explicit relationship of non-invasive brain imaging signals to the causative neural activity. The articles presented within this resulting eBook aim to both highlight the importance and improve the non-invasive estimation of neural signals in the human brain. To achieve this aim, the following issues are targeted:(1) The spatial limitations of source localization when using MEG/EEG.(2) The coupling of the BOLD signal to neural activity. Articles discuss how animal studies are fundamental in increasing our understanding of BOLD fMRI signals, analyze how non-neuronal cell types may contribute to the modulation of cerebral blood flow, and use modeling to improve our understanding of how local field potentials are linked to the BOLD signal.(3) The contribution of excitatory and inhibitory neuronal activity to the BOLD signal.(4) Assessment of neural connectivity through the use of resting state data, computational modeling and functional Diffusion Tensor Imaging (fDTI) approaches
    Keywords Science (General) ; Neurosciences. Biological psychiatry. Neuropsychiatry
    Size 1 electronic resource (142 p.)
    Publisher Frontiers Media SA
    Document type Book ; Online
    Note English ; Open Access
    HBZ-ID HT020090643
    ISBN 9782889199235 ; 2889199231
    Database ZB MED Catalogue: Medicine, Health, Nutrition, Environment, Agriculture

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  3. Article ; Online: A Live Experience of Four-Dimensional Structure.

    Tyler, Christopher W

    Perception

    2021  Volume 50, Issue 2, Page(s) 165–169

    Abstract: Selective attention is well known for 2D patterns and perceptual alternations are well established for 3D structures projected into 2D, such as the Necker cube. Here, these concepts are extended to the spatial fourth dimension in the form of the ... ...

    Abstract Selective attention is well known for 2D patterns and perceptual alternations are well established for 3D structures projected into 2D, such as the Necker cube. Here, these concepts are extended to the spatial fourth dimension in the form of the mathematical structure of the 4D hypercube. In orthographic projection, its 2D outline figure has multiple and highly dynamic percepts of up to 28 different 3D interpretations, which correspond to local 3D views of the 4D hypercube. Thus, the spontaneous operations of perceptual processing can provide direct insight into conceptual structure in the fourth dimension.
    MeSH term(s) Attention ; Humans
    Language English
    Publishing date 2021-01-17
    Publishing country United States
    Document type Journal Article
    ZDB-ID 185533-5
    ISSN 1468-4233 ; 0301-0066
    ISSN (online) 1468-4233
    ISSN 0301-0066
    DOI 10.1177/0301006620985387
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: The Interstitial Pathways as the Substrate of Consciousness: A New Synthesis.

    Tyler, Christopher W

    Entropy (Basel, Switzerland)

    2021  Volume 23, Issue 11

    Abstract: This paper considers three classes of analyses of the nature of consciousness: abstract theories of the functional organization of consciousness, and concrete proposals as to the neural substrate of consciousness, while providing a rationale for ... ...

    Abstract This paper considers three classes of analyses of the nature of consciousness: abstract theories of the functional organization of consciousness, and concrete proposals as to the neural substrate of consciousness, while providing a rationale for contesting non-neural and transcendental conceptualizations of consciousness. It indicates that abstract theories of the dynamic core of consciousness have no force unless they are grounded in the physiology of the brain, since the organization of dynamic systems, such as the Sun, could equally well qualify as conscious under such theories. In reviewing the wealth of studies of human consciousness since the mid-20th century, it concludes that many proposals for the particular neural substrate of consciousness are insufficient in various respects, but that the results can be integrated into a novel scheme that consciousness extends through a subcortical network of interlaminar structures from the brainstem to the claustrum. This interstitial structure has both the specificity and the extended connectivity to account for the array of reportable conscious experiences.
    Language English
    Publishing date 2021-10-31
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2014734-X
    ISSN 1099-4300 ; 1099-4300
    ISSN (online) 1099-4300
    ISSN 1099-4300
    DOI 10.3390/e23111443
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Cartography as Spatial Representation: A new assessment of the competing advantages and drawbacks across fields of science.

    Tyler, Christopher W

    Journal of perceptual imaging

    2021  Volume Human Vision and Electronic Imaging 2021, Page(s) 1561–15610

    Abstract: The history of cartography has been marked by the endless search for the perfect form for the representation of the information on a spherical surface manifold into the flat planar format of the printed page or computer screen. Dozens of cartographic ... ...

    Abstract The history of cartography has been marked by the endless search for the perfect form for the representation of the information on a spherical surface manifold into the flat planar format of the printed page or computer screen. Dozens of cartographic formats have been proposed over the centuries from ancient Greek times to the present. This is an issue not just for the mapping of the globe, but in all fields of science where spherical entities are found. The perceptual and representational advantages and drawbacks of many of these formats are considered, particularly in the tension between a unified representation, which is always distorted in some dimension, and a minimally distorted representation, which can only be obtained by segmentation into sectorial patches. The use of these same formats for the mapping of spherical manifolds are evaluated, from quantum physics through the mapping of the brain to the large-scale representation of the cosmos.
    Language English
    Publishing date 2021-01-18
    Publishing country United States
    Document type Journal Article
    ISSN 2575-8144
    ISSN (online) 2575-8144
    DOI 10.2352/ISSN.2470-1173.2021.11.HVEI-156
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Spatial summation for motion detection.

    Solomon, Joshua A / Nagle, Fintan / Tyler, Christopher W

    Vision research

    2024  Volume 221, Page(s) 108422

    Abstract: We used the psychophysical summation paradigm to reveal some spatial characteristics of the mechanism responsible for detecting a motion-defined visual target in central vision. There has been much previous work on spatial summation for motion detection ... ...

    Abstract We used the psychophysical summation paradigm to reveal some spatial characteristics of the mechanism responsible for detecting a motion-defined visual target in central vision. There has been much previous work on spatial summation for motion detection and direction discrimination, but none has assessed it in terms of the velocity threshold or used velocity noise to provide a measure of the efficiency of the velocity processing mechanism. Motion-defined targets were centered within square fields of randomly selected gray levels. The motion was produced within the disk-shaped target region by shifting the pixels rightwards for 0.2 s. The uniform target motion was perturbed by Gaussian motion noise in horizontal strips of 16 pixels. Independent variables were field size, the diameter of the disk target, and the variance of an independent perturbation added to the (signed) velocity of each 16-pixel strip. The dependent variable was the threshold velocity for target detection. Velocity thresholds formed swoosh-shaped (descending, then ascending) functions of target diameter. Minimum values were obtained when targets subtended approximately 2 degrees of visual angle. The data were fit with a continuum of models, extending from the theoretically ideal observer through various inefficient and noisy refinements thereof. In particular, we introduce the concept of sparse sampling to account for the relative inefficiency of the velocity thresholds. The best fits were obtained from a model observer whose responses were determined by comparing the velocity profile of each stimulus with a limited set of sparsely sampled "DoG" templates, each of which is the product of a random binary array and the difference between two 2-D Gaussian density functions.
    Language English
    Publishing date 2024-05-07
    Publishing country England
    Document type Journal Article
    ZDB-ID 200427-6
    ISSN 1878-5646 ; 0042-6989
    ISSN (online) 1878-5646
    ISSN 0042-6989
    DOI 10.1016/j.visres.2024.108422
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Leonardo da Vinci Probably Did Not Have Strabismus-Reply.

    Tyler, Christopher W

    JAMA ophthalmology

    2019  Volume 137, Issue 11, Page(s) 1332–1333

    Language English
    Publishing date 2019-11-14
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2701705-9
    ISSN 2168-6173 ; 2168-6165
    ISSN (online) 2168-6173
    ISSN 2168-6165
    DOI 10.1001/jamaophthalmol.2019.2218
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Ten Testable Properties of Consciousness.

    Tyler, Christopher W

    Frontiers in psychology

    2020  Volume 11, Page(s) 1144

    Abstract: This article develops a view of consciousness in the context of a new philosophical approach that invokes the concept of emergence, through which the operative principles of each level of organization of physical energy flow are functionally dissociated ... ...

    Abstract This article develops a view of consciousness in the context of a new philosophical approach that invokes the concept of emergence, through which the operative principles of each level of organization of physical energy flow are functionally dissociated from those of the levels below it, despite the continuity of the physical laws that govern them. The particular form of emergence that is the focus of the present analysis is the emergence of conscious mental processing from neural activity carried by the underlying biochemical principles of brain organization. Within this framework, a process model of consciousness is developed to account for many of the experienced aspects of consciousness, many that are rarely considered in the philosophical discourse. Each of these aspects is rigorously specified in terms of its definable properties. It is then analyzed in terms of specific empirical tests that can be used to determine its neural substrate and relevant data that implement such tests. The article concludes with an analysis of the evolutionary function of consciousness, and a critique of the Integrated Information Theory approach to defining its properties.
    Language English
    Publishing date 2020-06-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2563826-9
    ISSN 1664-1078
    ISSN 1664-1078
    DOI 10.3389/fpsyg.2020.01144
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: The Intersection of Visual Science and Art in Renaissance Italy.

    Tyler, Christopher W

    Perception

    2020  Volume 49, Issue 12, Page(s) 1265–1282

    Abstract: In the time of the Renaissance, a major aspect of vision science was understanding how spatial information projected to the viewpoint of the observer, that is, visual perspective, which is one of the primary cues to depth perception. Perspective ... ...

    Abstract In the time of the Renaissance, a major aspect of vision science was understanding how spatial information projected to the viewpoint of the observer, that is, visual perspective, which is one of the primary cues to depth perception. Perspective representation was thus an early form of virtual reality. Although accurate perspective representation was developed earlier in the 15th century, the first analytic perspective scheme was developed by Piero della Francesca, whose chef d'oeuvre is in the Church of San Francesco, Arezzo, in which the present lecture took place. The focus of the lecture was to evaluate some of the contributions of Piero della Francesca and his 15th-century contemporaries to the visual science, art and symbolism of his era, and its significance for the perception of depth structure from two-dimensional images.
    MeSH term(s) Art/history ; Cues ; History, 15th Century ; History, 16th Century ; Humans ; Italy ; Science/history ; Vision, Ocular
    Language English
    Publishing date 2020-12-10
    Publishing country United States
    Document type Historical Article ; Journal Article
    ZDB-ID 185533-5
    ISSN 1468-4233 ; 0301-0066
    ISSN (online) 1468-4233
    ISSN 0301-0066
    DOI 10.1177/0301006620974973
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Depth Cue Combination: A Quantitative Critique.

    Tyler, Christopher W

    Perception

    2019  Volume 48, Issue 9, Page(s) 765–768

    MeSH term(s) Bayes Theorem ; Cues ; Depth Perception ; Humans ; Pattern Recognition, Visual ; Visual Perception
    Language English
    Publishing date 2019-07-26
    Publishing country United States
    Document type Journal Article
    ZDB-ID 185533-5
    ISSN 1468-4233 ; 0301-0066
    ISSN (online) 1468-4233
    ISSN 0301-0066
    DOI 10.1177/0301006619865899
    Database MEDical Literature Analysis and Retrieval System OnLINE

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