In two experiments we examined the role of visual horizon information on absolute egocentric distance judgments to on-ground targets. Sedgwick [1983, in Human and Machine Vision (New York: Academic Press) pp 425-458] suggested that the visual system may utilize the angle of declination from a horizontal line of sight to the target location (horizon distance relation) to determine absolute distances on infinite ground surfaces. While studies have supported this hypothesis, less is known about the specific cues (vestibular, visual) used to determine horizontal line of sight. We investigated this question by requiring observers to judge distances under degraded vision given an unaltered or raised visual horizon. The results suggest that visual horizon information does influence perception of absolute distances as evident through two different action-based measures: walking or throwing without vision to previously viewed targets. Distances were judged as shorter in the presence of a raised visual horizon. The results are discussed with respect to how the visual system accurately determines absolute distance to objects on a finite ground plane and for their implications for understanding space perception in low-vision individuals.
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http://dx.doi.org/10.1068/p6843 | DOI Listing |
Sensors (Basel)
December 2024
Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Conventional Fourier domain Optical Coherence Tomography (FD-OCT) systems depend on resampling into a wavenumber () domain to extract the depth profile. This either necessitates additional hardware resources or amplifies the existing computational complexity. Moreover, the OCT images also suffer from speckle noise, due to systemic reliance on low-coherence interferometry.
View Article and Find Full Text PDFElife
January 2025
Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.
Data-driven models of neurons and circuits are important for understanding how the properties of membrane conductances, synapses, dendrites, and the anatomical connectivity between neurons generate the complex dynamical behaviors of brain circuits in health and disease. However, the inherent complexity of these biological processes makes the construction and reuse of biologically detailed models challenging. A wide range of tools have been developed to aid their construction and simulation, but differences in design and internal representation act as technical barriers to those who wish to use data-driven models in their research workflows.
View Article and Find Full Text PDFAccounting for why discrimination between different perceptual contents is not always accompanied conscious detection of that content remains a challenge for predictive processing theories of perception. Here, we test a hypothesis that detection is supported by a distinct inference within generative models of perceptual content. We develop a novel visual perception paradigm that probes such inferences by manipulating both expectations about stimulus content (stimulus identity) and detection of content (stimulus presence).
View Article and Find Full Text PDFEur J Neurosci
January 2025
Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany.
Within the reductionist framework, researchers in the special sciences formulate key terms and concepts and try to explain them with lower-level science terms and concepts. For example, behavioural vision scientists describe contrast perception with a psychometric function, in which the perceived brightness increases logarithmically with the physical contrast of a light patch (the Weber-Fechner law). Visual neuroscientists describe the output of neural circuits with neurometric functions.
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January 2025
Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
Functional compensation is a common notion in the neuroscience of healthy ageing, whereby older adults are proposed to recruit additional brain activity to compensate for reduced cognitive function. However, whether this additional brain activity in older participants actually helps their cognitive performance remains debated. We examined brain activity and cognitive performance in a human lifespan sample ( = 223) while they performed a problem-solving task (based on Cattell's test of fluid intelligence) during functional magnetic resonance imaging.
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