Download or read book Electrophysiological Correlates of Processing Unattended Objects in Visual Cognition written by Elley Wakui and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrophysiological Correlates of Object based Selective Attention written by Marla Raye Zinni and published by . This book was released on 2010 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: A visual stimulus may be selectively attended on the basis of its location in space, a specific feature, or as a whole object. While a relatively large amount of research has examined the neural basis of location-based and feature-based attentional selection, few studies have examined the neural correlates of the spread of attention from one feature of an object to another, reflecting the selection of an object as an "integrated feature ensemble" (Schoenfeld et al., 2003; O'Craven, Downing, & Kanwisher, 1999). The research in this dissertation examined the electrophysiological correlates of the spread of selective attention to a task-irrelevant color feature of an object using the event-related potential (ERP) brain imaging technique. The temporal dynamics of this spread of attention were examined for two classes of objects, grouped-arrays of lines (Study 1) and geometric shapes (Study 2). In each study, overlapping objects were presented and the participants' task was to sustain attention to one object versus another to judge a change in the thickness of one of the lines of the grid (Study 1) or a change in object shape (Study 2). On some trials, either the attended object or the unattended object was colored, and color was irrelevant to the task. Difference ERPs indicated that color was first encoded in the visual cortex by 100 ms. However, the effect of attention on the task-irrelevant color feature was evident in later ERP modulations. A bilateral parietal/occipital positivity beginning at 200 ms (Study 2) and a midline occipital negativity beginning at 280 ms (Studies 1 & 2) were associated with the selection of the irrelevant color of the attended object. Source localization analyses suggested that the neural generators of the attention-related facilitation of the irrelevant color feature were situated in ventral occipital cortical regions near color-selective cortical areas. These data provide further evidence for the "integrated competition" model (Duncan, 1996; 1997), which posits that the neural basis for the perceptual integration of an attended object consists of enhanced activity in the network of specialized modules that encode its individual features, including those that are not relevant to the immediate task.

Download or read book Visual Mismatch Negativity vMMN a Prediction Error Signal in the Visual Modality written by Gabor Stefanics and published by Frontiers Media SA. This book was released on 2015-06-04 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current theories of visual change detection emphasize the importance of conscious attention to detect unexpected changes in the visual environment. However, an increasing body of studies shows that the human brain is capable of detecting even small visual changes, especially if such changes violate non-conscious probabilistic expectations based on repeating experiences. In other words, our brain automatically represents statistical regularities of our visual environmental. Since the discovery of the auditory mismatch negativity (MMN) event-related potential (ERP) component, the majority of research in the field has focused on auditory deviance detection. Such automatic change detection mechanisms operate in the visual modality too, as indicated by the visual mismatch negativity (vMMN) brain potential to rare changes. VMMN is typically elicited by stimuli with infrequent (deviant) features embedded in a stream of frequent (standard) stimuli, outside the focus of attention. In this research topic we aim to present vMMN as a prediction error signal. Predictive coding theories account for phenomena such as mismatch negativity and repetition suppression, and place them in a broader context of a general theory of cortical responses. A wide range of vMMN studies has been presented in this Research Topic. Twelve articles address roughly four general sub-themes including attention, language, face processing, and psychiatric disorders. Additionally, four articles focused on particular subjects such as the oblique effect, object formation, and development and time-frequency analysis of vMMN. Furthermore, a review paper presented vMMN in a hierarchical predictive coding framework. Each paper in this Research Topic is a valuable contribution to the field of automatic visual change detection and deepens our understanding of the short term plasticity underlying predictive processes of visual perceptual learning.

Download or read book Cognitive Electrophysiology of Attention written by George R. Mangun and published by Academic Press. This book was released on 2013-08-31 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive Electrophysiology of Attention explores the fundamental mechanisms of attention and related cognitive functions from cognitive neuroscience perspectives. Attention is an essential cognitive ability that enables humans to process and act upon relevant information while ignoring distracting information, and the capacity to focus attention is at the core of mental functioning. Understanding the neural bases of human attention remains a key challenge for neuroscientists and psychologists, and is essential for translational efforts to treat attentional deficits in a variety of neurological and psychiatric disorders. Cognitive electrophysiology is at the center of a multidisciplinary approach that involves the efforts of psychologists, neuroscientists, neuropsychologists, psychiatrists, and neurologists to identify basic brain mechanisms and develop translational approaches to improve mental health. This edited volume is authored by leading investigators in the field and discusses methods focused on electrophysiological recordings in humans, including electroencephalography (EEG) and event-related potential (ERP) methods, and also incorporates evidence from functional magnetic resonance imaging (fMRI). Cognitive Electrophysiology of Attention illuminates specific models about attentional mechanisms in vision, audition, multisensory integration, memory, and semantic processing in humans. Provides an exhaustive overview of attention processes, going from normal functioning to the pathological, and using a combination of methodological tools An important reference for electrophysiology researchers looking at underlying attention processes rather than the methods themselves Enables researchers across a broad range of cognitive-process and methodological specialties to stay current on particular hypotheses, findings, and methods Edited and authored by the worldwide leaders in the field, affording the broadest, most expert coverage available

Download or read book Electrophysiological Investigation of Feature based Attention During Object Perception written by Boge Bobby Stojanoski and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Electrophysiological Correlate of Figure ground Organization in Human Visual Cortex written by Joseph Lloyd Brooks and published by . This book was released on 2006 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Localising the Electrophysiological Correlates Selective Attention Using High density Electroencephalography written by Dion Terry Henare and published by . This book was released on 2013 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: A typical visual scene includes many objects, but we are only aware of a small subset at any given time. In order to function in the world in spite of this limitation, we must selectively attend to goal-relevant objects while ignoring or suppressing irrelevant information. Previous research has used electroencephalography (EEG) to isolate brain potentials related to the selection of visual "targets", the suppression of "distractors", and processing in visual short term memory. Target selection is associated with the N2pc component of the visual evoked potential. N2pc typically occurs 180-250ms post-stimulus and manifests as increased negative voltage at posterior scalp electrodes contralateral to visual targets. A later potential with a more temporal scalp distribution, the Ptc, has been associated with the suppression of distractors, and a third final component, the SPCN, is believed to index visual short term memory processing. Here, we employed high-density EEG to provide evidence for the dissociation of N2pc, Ptc, and SPCN as well as estimates of their likely cortical generators. Participants responded to the orientation of a coloured target in amongst a circle of gray fillers while ignoring a coloured distractor. In half of the trials the target was lateralised while the distractor was on the midline, in the remaining trials this was reversed. This allowed us to dissociate the effects of targets and distractors. Our data show that the neural generators of the N2pc and Ptc are spatially dissociable, while the SPCN co-localises with the N2pc. This confirms previous indications that the N2pc, Ptc, and SPCN are functionally independent components of the VEP which index attentional selection, distractor suppression, and visual short term memory respectively.

Download or read book Interference Processing Within Visual Working Memory written by Marlene Rösner and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Inhibition in the process of feature binding written by Snehlata Jaswal and published by Frontiers E-books. This book was released on with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Feature binding is the process whereby different features such as shape, colour, size, orientation, location, etc. are linked together to form a coherent representation of the object. It is a ubiquitous physiological sequence and an essential phase in information processing, for it provides the basis of mental representations, which in turn, are requisite for all cognitive functions. It is important to realize though, that binding is not an isolated process. There are myriad stimuli impinging on our senses at all times, vying to gain entry into our consciousness. Further, not only does sensory input emanate from a complex, dynamic environment, but it also enters a neural system that is already activated by previous inputs and is oriented towards future goals. Which aspects of the momentary sensory input are selected for further processing depends as much on the state of the system as it does on the sensory input itself. Indeed, some fundamental questions one may ask about binding are whether, why, and how, some features are selected for binding at the cost of others. The bottom-up view of information processing is that the input received by the brain is processed in a largely automatic way to the higher centers in the brain. The physiological basis of binding is postulated to be either conjunctively coding neurons, or synchrony among participating neural networks to encode features and out of phase neural activity to encode separate objects. But, mere perceptual integration of features, whether by synchrony or by specialized neurons, does not even begin to capture the implication that binding results in coherent objects, fundamental for further information processing. An object is not only a bundle of features. At the very least, the features need to be integrated so that the object can be distinguished from other objects. This implies selection and manipulation of the basic information supplied by separate features. The top-down view of information processing contends that binding is more influenced by the reentrant processes (the downward and lateral feedback to the lower areas, emanating from the higher centers of the brain). Reentrant processes not only help to confirm what is correct but also resolve competition. These top-down processes are linked to attention and higher cognitive functions help select relevant input. We aim to debate what happens to the irrelevant information in the process of binding. Are irrelevant features simply lost from the system over time, or are they deliberately deleted? Is there any inhibitory process involved in binding? What is the empirical evidence for such a process at the behavioral level? Is such a process active and resource-demanding or relatively passive and automatic? What do neuropsychological studies show? What are the physiological underpinnings of such a process? How is it incorporated in computational models to increase our understanding of the binding process? The idea is to bring together diverse views on ‘Inhibition in Feature Binding’ with the ultimate aim of better understanding the process of binding and invoking informed and insightful future research.

Download or read book Encyclopedia of Neuroscience written by Marc D. Binder and published by Springer. This book was released on 2008-10-13 with total page 4398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 5000-page masterwork is literally the last word on the topic and will be an essential resource for many. Unique in its breadth and detail, this encyclopedia offers a comprehensive and highly readable guide to a complex and fast-expanding field. The five-volume reference work gathers more than 10,000 entries, including in-depth essays by internationally known experts, and short keynotes explaining essential terms and phrases. In addition, expert editors contribute detailed introductory chapters to each of 43 topic fields ranging from the fundamentals of neuroscience to fascinating developments in the new, inter-disciplinary fields of Computational Neuroscience and Neurophilosophy. Some 1,000 multi-color illustrations enhance and expand the writings.

Download or read book Electrophysiological Correlates of Cognitive Processing in Adolescents Reporting Psychotic like Experiences written by Caroline Rawdon and published by . This book was released on 2013 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrophysiological Correlates of the Influences of Past Experience on Conscious and Unconscious Figure Ground Perception written by Logan Thomas Trujillo and published by . This book was released on 2007 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Figure-ground perception can be modeled as a competitive process with mutual inhibition between shape properties on opposite sides of an edge. This dissertation reports brain-based evidence that such competitive inhibition can be induced by access to preexisting object memory representations during figure assignment. Silhouette stimuli were used in which the balance of properties along an edge biased the inner, bounded, region to be seen as a novel figure. Experimental silhouettes (EXP) suggested familiar objects on their outside edges, which nonetheless appeared as shapeless grounds. Control silhouettes (CON) suggested novel shapes on the outside. In an initial task, human observers categorized masked EXP and CON silhouettes (175 ms exposure) as"novel"versus a third group of silhouettes depicting"familiar"objects on the inside. Signal detection measures verified that observers were unconscious of the familiar shapes within the EXP stimuli. Across three experiments, novel categorizations were highly accurate with shorter RTs for EXP than CON. Event-related potential (ERP) indices of observers' brain activity (Experiments 2 and 3) revealed a Late Potential (3̃00 ms) to be less positive for EXP than CON, a reduction in neural activity consistent with the presence of greater competitive inhibition for EXP stimuli. After controlling for stimulus confounds (Experiment 3), the P1 ERP (1̃00 ms) was larger for EXP than CON conditions, perhaps reflecting unconscious access to object memories. In a second task, observers were informed about familiar shapes suggested on the outsides of the EXP silhouettes before viewing masked (Experiments 1 and 2) or unmasked (Experiment 3) EXP and CON silhouettes to report whether they saw familiar shapes on the outside. Experiment 3 observers were more accurate to categorize CON vs. EXP stimuli as novel vs. familiar, with shorter RTs for EXP than CON. Task 2 N170 ERPs (1̃70 ms) were larger for EXP than CON in Experiments 2 and 3, reflecting the conscious perception of familiar shape in the outsides of EXP silhouettes. LP magnitudes were greater for CON than EXP, although ERP polarity was dependent on the presence/absence of a mask. Task 2 LPs may reflect competitive inhibition or longer processing times for CON stimuli.

Download or read book Electrophysiological Correlates of Visual Object Category Formation in a Prototype distortion Task written by Stephanie M. Long and published by . This book was released on 2019 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: In perceptual learning studies, participants engage in extensive training in the discrimination of visual stimuli in order to modulate perceptual performance. Much of the literature in perceptual learning has looked at the induction of the reorganization of low-level representations in V1. However, much remains to be understood about the mechanisms behind how the adult brain (an expert in visual object categorization) extracts high-level visual objects from the environment and categorically represents them in the cortical visual hierarchy. Here, I used event-related potentials (ERPs) to investigate the neural mechanisms involved in object representation formation during a hybrid visual search and prototype distortion category learning task. EEG was continuously recorded while participants performed the hybrid task, in which a peripheral array of four dot patterns was briefly flashed on a computer screen. In half of the trials, one of the four dot patterns of the array contained the target, a distorted prototype pattern. The remaining trials contained only randomly generated patterns. After hundreds of trials, participants learned to discriminate the target pattern through corrective feedback. A multilevel modeling approach was used to examine the predictive relationship between behavioral performance over time and two ERP components, the N1 and the N250. The N1 is an early sensory component related to changes in visual attention and discrimination (Hopf et al., 2002; Vogel & Luck, 2000). The N250 is a component related to category learning and expertise (Krigolson et al., 2009; Scott et al., 2008; Tanaka et al., 2006). Results indicated that while N1 amplitudes did not change with improved performance, increasingly negative N250 amplitudes did develop over time and were predictive of improvements in pattern detection accuracy.

Download or read book Cognitive mechanisms of visual attention working memory emotion and their interactions written by Chaoxiong Ye and published by Frontiers Media SA. This book was released on 2023-08-17 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrophysiological Correlates of Information Processing in Visual Hemineglect microform written by Christopher A. Dywan and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2002 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Neural Bases of Multisensory Processes written by Micah M. Murray and published by CRC Press. This book was released on 2011-08-25 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has become accepted in the neuroscience community that perception and performance are quintessentially multisensory by nature. Using the full palette of modern brain imaging and neuroscience methods, The Neural Bases of Multisensory Processes details current understanding in the neural bases for these phenomena as studied across species, stages of development, and clinical statuses. Organized thematically into nine sub-sections, the book is a collection of contributions by leading scientists in the field. Chapters build generally from basic to applied, allowing readers to ascertain how fundamental science informs the clinical and applied sciences. Topics discussed include: Anatomy, essential for understanding the neural substrates of multisensory processing Neurophysiological bases and how multisensory stimuli can dramatically change the encoding processes for sensory information Combinatorial principles and modeling, focusing on efforts to gain a better mechanistic handle on multisensory operations and their network dynamics Development and plasticity Clinical manifestations and how perception and action are affected by altered sensory experience Attention and spatial representations The last sections of the book focus on naturalistic multisensory processes in three separate contexts: motion signals, multisensory contributions to the perception and generation of communication signals, and how the perception of flavor is generated. The text provides a solid introduction for newcomers and a strong overview of the current state of the field for experts.

Download or read book The Oxford Handbook of Event Related Potential Components written by Steven J. Luck and published by OUP USA. This book was released on 2012-01-12 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oxford Handbook of Event-Related Potential Components provides a detailed and comprehensive overview of the major ERP components. It covers components related to multiple research domains, including perception, cognition, emotion, neurological and psychiatric disorders, and lifespan development.