Cortical Mechanisms Of Selective Attention To Spatial And Non Spatial Stimulus Features
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Cortical Mechanisms Of Selective Attention To Spatial And Non Spatial Stimulus Features
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Author : Antigona Martinez-Quintero
language : en
Publisher:
Release Date : 1999
Cortical Mechanisms Of Selective Attention To Spatial And Non Spatial Stimulus Features written by Antigona Martinez-Quintero and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Neural circuitry categories.
Mechanisms Of Visual Attention
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Author : Werner X. Schneider
language : en
Publisher: Psychology Press
Release Date : 1998
Mechanisms Of Visual Attention written by Werner X. Schneider and has been published by Psychology Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Psychology categories.
In order to produce coherent behaviour in a complex world, forms of visual attention are necessary in order for us to select appropriate objects for action. Over the past ten years, there have been considerable advances in research into visual attention, with many of these advances linked to interdisciplinary research in experimental psychology, neuropsychology, neurophysiology and functional imaging. This work has begun to allow us to understand not only the functional properties of visual attention, but also how attentional processes are localized in the brain: the cognitive neuroscience of visual attention. This special issue draws together research from leading figures in this field, to highlight recent progress in understanding how selective processes operate in perception and action.
Neural Mechanisms Of Spatial Attention
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Author : Ashley Royston
language : en
Publisher:
Release Date : 2018
Neural Mechanisms Of Spatial Attention written by Ashley Royston and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
Elucidating the neural bases of selective attention continues to be a key challenge for psychologists, vision scientists and cognitive neuroscientists. It also represents an essential aim in translational efforts to measure, treat and prevent visual and attentional deficits, to improve teaching and learning, and to tailor automated situational awareness and alerting systems to human capabilities. Past human functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) studies, as well as animal electrophysiological studies, have provided considerable information about the temporal properties, neuroanatomical substrates, and cellular- and synaptic-level mechanisms underlying attention. Despite substantial convergence in the mechanisms of attention revealed by these different approaches, there remain significant unresolved quandaries in the scientific literature. In particular, it is currently debated whether attention can influence neural activity during the initial feedforward wave of visual processing in human primary visual cortex (V1). FMRI in humans and cellular recordings in monkeys both suggest spatial attention can influence afferent sensory processing in V1. In sharp contrast, however, such effects of attention have not been reliably reported for human EEG recordings; the short-latency C1 component of the visually evoked event-related potential (ERP) that is generated in V1 is typically not affected by selective attention. Given the fMRI findings and the animal studies, what can explain this discrepancy? FMRI activations are tied to slow changes in cerebral hemodynamics that cannot distinguish between attention effects on incoming signals and activations due to longer-latency feedback activation of V1 from higher stages of visual processing—therefore, fMRI evidence is equivocal regarding whether attention-related V1 activations represent modulations of feedforward or feedback V1 activity. However, human and animal electrophysiology both provide the temporal resolution to distinguished between initial afferent volleys and feedback activity, making it difficult to reconcile the positive findings in monkeys and the negative findings in humans. The overarching hypothesis of this dissertation is that differences in the methods and paradigms between monkey and human studies could contribute to the differences in attention effects in V1. Specifically, monkey studies typically use continuous stimulation that is arguably more similar to natural vision than the punctate stimulation paradigms (e.g., trial-by-trial spatial cuing) often used in humans to study the effects of attention on sensory processing. Ongoing stimulation may trigger attention-related feedback signals from higher areas onto V1 that might not arise, or might not be observable, when simple, single, isolated stimuli are used. To investigate whether the nature of ongoing visual stimulation may account for some of the discrepancies reported in the literature, this dissertation examines human ERPs recorded during selective attention in six variations of a novel spatial attention task that builds on a paradigm successfully used to reveal V1 attention effects in nonhuman primates. Using this task, significant effects of spatial attention were observed on the amplitude of the C1 ERP in humans (Chapter 2). The addition of high-resolution eye gaze monitoring, however, demonstrated that small, systematic deviations of eye gaze in the direction of the cue hemifield likely contributed to the Chapter 2 finding, and when data from trials with deviations of eye gaze were eliminated, no attentional modulation on the C1 ERP remained (Chapter 3). Therefore, the main hypothesis that stimulus-triggered feedback attentional modulation of V1 signals should be observed as changes in C1 ERP amplitude, was not supported. Although the present findings do not explain the differences between spatial attention effects in monkey and human V1, they do provide additional support for the model that spatial attention effects observed using fMRI in humans is likely not the result of changes in input signal processing in V1, but instead reflects later recurrent activation of V1 that serves other computational purposes.
Neurobiology Of Attention
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Author : Laurent Itti
language : en
Publisher: Elsevier
Release Date : 2005-03-31
Neurobiology Of Attention written by Laurent Itti and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-03-31 with Psychology categories.
A key property of neural processing in higher mammals is the ability to focus resources by selectively directing attention to relevant perceptions, thoughts or actions. Research into attention has grown rapidly over the past two decades, as new techniques have become available to study higher brain function in humans, non-human primates, and other mammals. Neurobiology of Attention is the first encyclopedic volume to summarize the latest developments in attention research.An authoritative collection of over 100 chapters organized into thematic sections provides both broad coverage and access to focused, up-to-date research findings. This book presents a state-of-the-art multidisciplinary perspective on psychological, physiological and computational approaches to understanding the neurobiology of attention. Ideal for students, as a reference handbook or for rapid browsing, the book has a wide appeal to anybody interested in attention research. * Contains numerous quick-reference articles covering the breadth of investigation into the subject of attention* Provides extensive introductory commentary to orient and guide the reader* Includes the most recent research results in this field of study
Posterior Parietal Cortex And Non Spatial Attention Control
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Author : Luana Caselli
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2010-06
Posterior Parietal Cortex And Non Spatial Attention Control written by Luana Caselli and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-06 with categories.
Goals dominate primate behavior. Almost all intended behaviors depend on the acquisition of "cognitive sets" endowing us with expectations about classes of stimuli and responses (S-R sets) appropriate to achieve a particular goal in a given context. Selective attention allows to switch between competing cognitive sets by focusing onto the currently relevant S-R sets while disengaging from other interfering S-R sets. The question whether non- human primates provide an appropriate model for human task-switching has not been completely answered. Posterior Parietal Cortex (PPC) has long been known to be fundamental to spatial attention. The aim of this study was to explore the role of PPC in non- spatial forms of attention, with particular interest in the representation of cognitive sets. To tackle this issue, the activity of single neurons was recorded from area 7a of one monkey tested with a task-switching paradigm. The obtained results support the idea that PPC is undoubtedly involved in cognitive domains well beyond spatial processing, contributing to the encoding of cognitive sets essential to primate goal-directed behaviors.
The Neuropsychology Of Attention
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Author : Ronald A. Cohen
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-03-09
The Neuropsychology Of Attention written by Ronald A. Cohen and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-03-09 with Medical categories.
As you read this, you are probably unaware of how your left foot feels in your shoe. Although your brain was receiving sensory input from this foot, you were not aware of your foot because you were reading and not attending to it. However, this discussion led you to move your attention to your left foot and to become aware of it. When I was a medical student, I saw a patient who was unaware of both the left side of his body and the left side of his environment. Unlike people in normal health, who when instructed can become aware of the left side of the body; this patient could not be made aware of his left arm or the left side of his environment. The patient's defect was so profound that despite being hungry he was unaware of food on the left side of his tray and did not recognize that his left arm belonged to him. This left-sided body and spatial unawareness could not be accounted for by a primary sensory defect. Although I knew that this man suffered from a large right-hemisphere stroke, I did not know the brain mechanisms that accounted for this profound example of unawareness. It was not until I had almost completed my neurology training in 1969 that I was able to return to this problem. At that time, most neuropsychological research was directed at understanding the language disorders associated with brain disease.
The Functional Role Of Spatial Selective Attention In Spatial Working Memory
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Author : Amishi Parag Jha
language : en
Publisher:
Release Date : 1998
The Functional Role Of Spatial Selective Attention In Spatial Working Memory written by Amishi Parag Jha and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
Attention Voluntary Contraction And Event Related Cerebral Potentials
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Author : John E. Desmedt
language : en
Publisher: S. Karger AG (Switzerland)
Release Date : 1977
Attention Voluntary Contraction And Event Related Cerebral Potentials written by John E. Desmedt and has been published by S. Karger AG (Switzerland) this book supported file pdf, txt, epub, kindle and other format this book has been release on 1977 with Medical categories.
The Neuropsychology Of Mental Illness
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Author : Stephen J. Wood
language : en
Publisher: Cambridge University Press
Release Date : 2009-10
The Neuropsychology Of Mental Illness written by Stephen J. Wood and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009-10 with Medical categories.
Describes neuropsychological approaches to the investigation, description, measurement and management of a wide range of mental illnesses.
Mechanisms Of Attentional Filtering In Neuronal Ensembles Of Primate Prefrontal Cortex
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Author : Theda Backen
language : en
Publisher:
Release Date : 2017
Mechanisms Of Attentional Filtering In Neuronal Ensembles Of Primate Prefrontal Cortex written by Theda Backen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
"Visual attention describes the cognitive mechanism that selectively filters behaviorally relevant from irrelevant information. Neurophysiological studies using single unit recordings have uncovered a network of fronto-parietal brain areas involved in the allocation of attention. However, important details regarding how ensembles of simultaneously active neurons support this behavior remain poorly documented. In this doctoral thesis, I investigated how neuronal ensembles within the primate lateral prefrontal cortex (LPFC) underlie attentional filtering under varying behavioral conditions. I first showed that ensemble activity correlates with behavior in a task during which the task difficulty was manipulated by changing the distance between ordinally-ranked stimuli. Behavioral performance improved with decreasing task difficulty and similarly, neuronal ensembles encoded the spatial location of the attended stimulus more accurately for easier trials. Furthermore, interactions between similarly and dissimilarly tuned neurons also co-varied with task difficulty. However, these patterns of spike count correlations had no measurable effect on information coding in the neuronal population. Instead, I postulate a model that describes all measured ensemble properties, in which these spike count correlations reflect anatomical and functional connectivity patterns of the underlying neuronal circuits. Second, I investigated how LPFC neurons encode different task-relevant stimulus parameters. I found evidence that neuronal ensembles encode both spatial and non-spatial features of attended stimuli more accurately than single units. Those results indicate that LPFC may be relevant for both types of attention but also highlight that the information contained in such maps cannot be predicted from the responses of individual units. Finally, I examined how the spatial arrangement of stimuli modulates attention. When two stimuli were presented within the same hemifield, behavioral performance as well as neuronal attentional filtering performance was impaired. I offer evidence that a change in the underlying correlational structure of the ensemble may affect information coding. These results give credence to the hypothesis that attentional capacities are hemifield-independent. Taken together, these results provide important new insight into the neural ensemble correlates of visual attention. Ensemble activity in the lateral prefrontal cortex of primates appears to be critically involved in attentional filtering under a variety of behavioral conditions. " --