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Learning to see (better): Improving visual deficits with perceptual learning

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196036 Year: Pages: 95 DOI: 10.3389/978-2-88919-603-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Psychology
Added to DOAB on : 2016-08-16 10:34:25
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Perceptual learning can be defined as a long lasting improvement in a perceptual skill following a systematic training, due to changes in brain plasticity at the level of sensory or perceptual areas. Its efficacy has been reported for a number of visual tasks, such as detection or discrimination of visual gratings (De Valois, 1977; Fiorentini & Berardi, 1980, 1981; Mayer, 1983), motion direction discrimination (Ball & Sekuler, 1982, 1987; Ball, Sekuler, & Machamer, 1983), orientation judgments (Fahle, 1997; Shiu & Pashler, 1992; Vogels & Orban, 1985), hyperacuity (Beard, Levi, & Reich, 1995; Bennett & Westheimer, 1991; Fahle, 1997; Fahle & Edelman, 1993; Kumar & Glaser, 1993; McKee & Westheimer, 1978; Saarinen & Levi, 1995), visual search tasks (Ahissar & Hochstein, 1996; Casco, Campana, & Gidiuli, 2001; Campana & Casco, 2003; Ellison & Walsh, 1998; Sireteanu & Rettenbach, 1995) or texture discrimination (Casco et al., 2004; Karni & Sagi, 1991, 1993). Perceptual learning is long-lasting and specific for basic stimulus features (orientation, retinal position, eye of presentation) suggesting a long-term modification at early stages of visual analysis, such as in the striate (Karni & Sagi, 1991; 1993; Saarinen & Levi, 1995; Pourtois et al., 2008) and extrastriate (Ahissar & Hochstein, 1996) visual cortex. Not confined to a basic research paradigm, perceptual learning has recently found application outside the laboratory environment, being used for clinical treatment of a series of visually impairing conditions such as amblyopia (Levi & Polat, 1996; Levi, 2005; Levi & Li, 2009, Polat et al., 2004; Zhou et al., 2006), myopia (Tan & Fong, 2008) or presbyopia (Polat, 2009). Different authors adopted different paradigms and stimuli in order to improve malfunctioning visual abilities, such as Vernier Acuity (Levi, Polat & Hu, 1997), Gratings detection (Zhou et al., 2006), oculomotor training (Rosengarth et al., 2013) and lateral interactions (Polat et al., 2004). The common result of these studies is that a specific training produces not only improvements in trained functions, but also in other, untrained and higher-level visual functions, such as visual acuity, contrast sensitivity and reading speed (Levi et al, 1997a, 1997b; Polat et al., 2004; Polat, 2009; Tan & Fong, 2008). More recently (Maniglia et al. 2011), perceptual learning with the lateral interactions paradigm has been successfully used for improving peripheral vision in normal people (by improving contrast sensitivity and reducing crowding, the interference in target discrimination due to the presence of close elements), offering fascinating new perspectives in the rehabilitation of people who suffer of central vision loss, such as maculopathy patients, partially overcoming the structural differences between fovea and periphery that limit the vision outside the fovea. One of the strongest point, and a distinguishing feature of perceptual learning, is that it does not just improve the subject’s performance, but produces changes in brain’s connectivity and efficiency, resulting in long-lasting, enduring neural changes. By tailoring the paradigms on each subject’s needs, perceptual learning could become the treatment of choice for the rehabilitation of visual functions, emerging as a simple procedure that doesn’t need expensive equipment.

Neurovision: Neural bases of binocular vision and coordination and their implications in visual training programs

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196555 Year: Pages: 264 DOI: 10.3389/978-2-88919-655-5 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
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Binocular vision is achieved by five neurovisual systems originating in the retina but varying in their destination within the brain. Two systems have been widely studied: the retino-tectal or retino-collicular route, which subserves an expedient and raw estimate of the visual scene through the magnocellular pathway, and the retino-occipital or retino-cortical route, which allows slower but refined analysis of the visual scene through the parvocellular pathway. But there also exist further neurovisual systems: the retino-hypothalamic, retino-pretectal, and accessory optic systems, which play a crucial role in vision though they are less understood. The retino-pretectal pathway projecting onto the pretectum is critical for the pupillary or photomotor reflex. The retino-hypothalamic pathway projecting onto the suprachiasmatic nucleus regulates numerous behavioral and biological functions as well as circadian rhythms. The accessory optic system targeting terminal lateral, medial and dorsal nuclei through the paraoptic fasciculus plays a role in head and gaze orientation as well as slow movements. Taken together, these neurovisual systems involve 60% of brain activity, thus highlighting the importance of vision in the functioning and regulation of the central nervous system. But vision is first and foremost action, which makes perception impossible without movement. Binocular coordination is a prerequisite for binocular fusion of the object of interest on the two foveas, thus ensuring visual perception. The retino-collicular pathway is sufficient to elicit reflexive eye movements with short latencies. Thanks to its motor neurons, the superior colliculus activates premotor neurons, which themselves activate motor neurons of the oculomotor, trochlear and abducens nuclei. At a higher level, a cascade of neural mechanisms participates in the control of decisional eye movements. The superior colliculus is controlled by the substancia nigra pars reticulata, which is itself gated by subcortical structures such as the dorsal striatum. The superior colliculus is also inhibited by the dorsolateral prefrontal cortex through a direct prefrontotectal tract. Cortical areas are crucial for the triggering of eye movements: the frontal eye field, supplementary eye field, and parietal eye field. Finally the cerebellum maintains accuracy. The focus of the present research topic, entitled Neural bases of binocular vision and coordination and their implications in visual training programs, is to review the most recent findings in brain imaging and neurophysiology of binocular vision and coordination in humans and animals with frontally-placed eyes. The emphasis is put on studies that enable transfer of knowledge toward visual training programs targeting visual field defects (e.g., hemianopia) and binocular functional disorders (e.g., amblyopia).

What can simple brains teach us about how vision works

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196784 Year: Pages: 290 DOI: 10.3389/978-2-88919-678-4 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
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Vision is the process of extracting behaviorally-relevant information from patterns of light that fall on retina as the eyes sample the outside world. Traditionally, nonhuman primates (macaque monkeys, in particular) have been viewed by many as the animal model-of-choice for investigating the neuronal substrates of visual processing, not only because their visual systems closely mirror our own, but also because it is often assumed that “simpler” brains lack advanced visual processing machinery. However, this narrow view of visual neuroscience ignores the fact that vision is widely distributed throughout the animal kingdom, enabling a wide repertoire of complex behaviors in species from insects to birds, fish, and mammals. Recent years have seen a resurgence of interest in alternative animal models for vision research, especially rodents. This resurgence is partly due to the availability of increasingly powerful experimental approaches (e.g., optogenetics and two-photon imaging) that are challenging to apply to their full potential in primates. Meanwhile, even more phylogenetically distant species such as birds, fish, and insects have long been workhorse animal models for gaining insight into the core computations underlying visual processing. In many cases, these animal models are valuable precisely because their visual systems are simpler than the primate visual system. Simpler systems are often easier to understand, and studying a diversity of neuronal systems that achieve similar functions can focus attention on those computational principles that are universal and essential. This Research Topic provides a survey of the state of the art in the use of animal models of visual functions that are alternative to macaques. It includes original research, methods articles, reviews, and opinions that exploit a variety of animal models (including rodents, birds, fishes and insects, as well as small New World monkey, the marmoset) to investigate visual function. The experimental approaches covered by these studies range from psychophysics and electrophysiology to histology and genetics, testifying to the richness and depth of visual neuroscience in non-macaque species.

Hierarchical Object Representations in the Visual Cortex and Computer Vision

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197989 Year: Pages: 290 DOI: 10.3389/978-2-88919-798-9 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-02-03 17:04:57
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Over the past 40 years, neurobiology and computational neuroscience has proved that deeper understanding of visual processes in humans and non-human primates can lead to important advancements in computational perception theories and systems. One of the main difficulties that arises when designing automatic vision systems is developing a mechanism that can recognize - or simply find - an object when faced with all the possible variations that may occur in a natural scene, with the ease of the primate visual system. The area of the brain in primates that is dedicated at analyzing visual information is the visual cortex. The visual cortex performs a wide variety of complex tasks by means of simple operations. These seemingly simple operations are applied to several layers of neurons organized into a hierarchy, the layers representing increasingly complex, abstract intermediate processing stages. In this Research Topic we propose to bring together current efforts in neurophysiology and computer vision in order 1) To understand how the visual cortex encodes an object from a starting point where neurons respond to lines, bars or edges to the representation of an object at the top of the hierarchy that is invariant to illumination, size, location, viewpoint, rotation and robust to occlusions and clutter; and 2) How the design of automatic vision systems benefit from that knowledge to get closer to human accuracy, efficiency and robustness to variations.

Perceiving and Acting in the Real World: From Neural Activity to Behavior

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450282 Year: Pages: 280 DOI: 10.3389/978-2-88945-028-2 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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One remarkable ability of the human brain is to process large amounts of information about our surroundings to allow us to interact effectively with them. In everyday life, the most common way to interact with objects is by reaching, grasping, lifting and manipulating them. Although these may sound like simple tasks, the perceptual properties of the target object, such as its location, size, shape, and orientation all need to be processed in order to set the movement parameters that allow an accurate reach-to-grasp-to lift movement. Several brain areas work in concert to process this outstanding amount of visual information and drive the execution of a motor plan in just a few hundred milliseconds. How are these processes orchestrated? In developing this type of comprehensive knowledge about the interactions between objects perception and goal-directed actions, we have a window into the mechanisms underlying the functioning of the visuo-motor system. With this research topic we aim to further understand the neural mechanisms that mediate our interactions with the world. Therefore, we particularly encourage submission of papers that attempt to relate such findings to real-world situations by investigating behavioural and neural correlates of information processing related to eye-hand coordination and visually-guided actions, including reaching, grasping, and lifting movements. This topic welcomes submissions of original research using any relevant techniques and methods, from behavioural kinematics/kinetics, to neuroimaging and transcranial magnetic stimulation (TMS), as well as neuropsychological studies.One remarkable ability of the human brain is to process large amounts of information about our surroundings to allow us to interact effectively with them. In everyday life, the most common way to interact with objects is by reaching, grasping, lifting and manipulating them. Although these may sound like simple tasks, the perceptual properties of the target object, such as its location, size, shape, and orientation all need to be processed in order to set the movement parameters that allow an accurate reach-to-grasp-to lift movement. Several brain areas work in concert to process this outstanding amount of visual information and drive the execution of a motor plan in just a few hundred milliseconds. How are these processes orchestrated? In developing this type of comprehensive knowledge about the interactions between objects perception and goal-directed actions, we have a window into the mechanisms underlying the functioning of the visuo-motor system. With this research topic we aim to further understand the neural mechanisms that mediate our interactions with the world. Therefore, we particularly encourage submission of papers that attempt to relate such findings to real-world situations by investigating behavioural and neural correlates of information processing related to eye-hand coordination and visually-guided actions, including reaching, grasping, and lifting movements. This topic welcomes submissions of original research using any relevant techniques and methods, from behavioural kinematics/kinetics, to neuroimaging and transcranial magnetic stimulation (TMS), as well as neuropsychological studies.

Coding Properties in Invertebrate Sensory Systems

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451067 Year: Pages: 227 DOI: 10.3389/978-2-88945-106-7 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Animals rely on sensory input from their environment for survival and reproduction. Depending on the importance of a signal for a given species, accuracy of sensory coding might vary from pure detection up to precise coding of intensity, quality and temporal features of the signal. Highly sophisticated sense organs and related central nervous sensory pathways can be of utmost importance for animals in a complex environment and when using advanced communication systems. In sensory systems different anatomical and physiological features have evolved to optimally encode behaviourally relevant signals at the level of sense organs and central processing. The wide range of organizational complexity, in combination with their relatively simple and accessible nervous systems, makes invertebrates excellent models to study general sensory coding principles. The contributions to this e-book illustrate on one hand particular features of specific sensory systems, and on the other hand indicate not only common features of sensory coding across invertebrate phyla, but also similar processing principles of complex stimuli between different sensory modalities. The chapters show that the extraction of behaviourally relevant signals from all environmental stimuli, as well as the detection of low intensity signals and the analysis of temporal features can be similar across sensory modalities, including olfaction, vision, mechanoreception, and heat perception.

Modeling of Visual Cognition, Body Sense, Motor Control and Their Integrations

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451098 Year: Pages: 134 DOI: 10.3389/978-2-88945-109-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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The interdisciplinary studies between neuroscience and information science have greatly promoted the development of these two fields. The achievements of these studies can help humans understand the essence of biological systems, provide computational platforms for biological experiments, and improve the intelligence and performance of the algorithms in information science. This research topic is focused on the computational modeling of visual cognition, body sense, motor control and their integrations. Firstly, the modeling and simulation of vision and body sense are achieved by 1) understanding neural mechanism underlying sensory perception and cognition, and 2) mimicking accordingly the structures and mechanisms of their signal propagation pathways. The achievement of this procedure could provide neural findings for better encoding and decoding visual and somatosensory perception of humans, and help robots or systems build humanoid robust vision, body sensing, and various emotions. Secondly, the modeling and simulation of the motor system of the primate are achieved by mimicking the coordination of bones, muscles and joints and the control mechanisms of the neural system in the brain and spinal cord. This procedure could help robots achieve fast, robust and accurate manipulations and be used for safe human-computer interaction. Finally, by integrating them, more complete and intelligent systems/robots could be built to accomplish various tasks self-adaptively and automatically.

Alexander von Humboldt, da 250 anni il teorizzatore dello studio interdisciplinare dell’ambiente (Book chapter)

Book title: Eighth International Symposium “Monitoring of Mediterranean Coastal Areas. Problems and Measurement Techniques”

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Book Series: Proceedings e report ISSN: 27045846 ISBN: 9788855181471 Year: Volume: 126 DOI: 10.36253/978-88-5518-147-1.01
Publisher: Firenze University Press
Subject: Forestry
Added to DOAB on : 2020-11-26 11:35:25
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In 19th century birth of the term scientist led to beginning of Sciences professionalization and end of Nature eclectic scholar, of which Humboldt was the last exponent. Humboldt managed to connect all disciplines in a holistic vision of the world: organic and inorganic nature form a single system of active forces; all the organisms of Earth are linked as a family sharing same home. Today, given the anthropogenic damage caused to Nature, it needs to reconsider his unified vision, establishing connections between scholars of various disciplines, for an organic and global vision of Environment.

Visual perception and visual cognition in healthy and pathological ageing

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192533 Year: Pages: 183 DOI: 10.3389/978-2-88919-253-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Psychology
Added to DOAB on : 2015-11-16 15:44:59
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Our understanding of visual perception and visual cognition has advanced considerably over the last decades. The effects of ageing on visual perception and visual cognition are less well understood. This Research Topic features state-of-the-art approaches to determining the effects of ageing on visual perception, visual attention, visual memory and visually guided behaviour. Studies using methods that incorporate psychophysics, eye movements, electrophysiology, structural and functional neuroimaging, as well as computational modelling are included. In addition to the focus on how ageing effects normal vision, the topic also includes studies on the effects of pathological ageing in the retina (e.g., age-related macular degeneration) and the brain (e.g., neurodegenerative disorders) on vision and visual cognition.

Integrating Computational and Neural Findings in Visual Object Perception

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198733 Year: Pages: 137 DOI: 10.3389/978-2-88919-873-3 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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The articles in this Research Topic provide a state-of-the-art overview of the current progress in integrating computational and empirical research on visual object recognition. Developments in this exciting multidisciplinary field have recently gained momentum: High performance computing enabled breakthroughs in computer vision and computational neuroscience. In parallel, innovative machine learning applications have recently become available for datamining the large-scale, high resolution brain data acquired with (ultra-high field) fMRI and dense multi-unit recordings. Finally, new techniques to integrate such rich simulated and empirical datasets for direct model testing could aid the development of a comprehensive brain model. We hope that this Research Topic contributes to these encouraging advances and inspires future research avenues in computational and empirical neuroscience.

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