Download or read book Representation of Natural Image Sequences in the Primate Visual System written by Yoon Ho Bai and published by . This book was released on 2020 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental goal of sensory processing is predicting the future state of the environment. Visual prediction is difficult because the stream of images on the retina evolves according to irregular, curved trajectories. We posit that the visual system seeks to transform natural inputs such that neural representations follow straighter and more predictable trajectories. Previous work has provided psychophysical evidence for this hypothesis by showing that the human visual system selectively straightens the temporal trajectories of natural movies, thus facilitating their extrapolation. In this thesis, I investigate the neural basis of perceptual straightening. We hypothesize that perceptual straightening is achieved through a series of cascaded transformations and found supporting evidence from psychophysical and neurophysiological measurements. We estimated the curvature of internal trajectories from human perceptual judgements across distinct sub-regions of the visual field. Perceptual results suggest that computations that underlie object recognition overlap with those that straighten natural movies, thereby revealing deficits in both processes--crowding and absence of straightening in the periphery. We posit that straightening occurs at multiple stages in the ventral stream as it is linked to recognizing objects. Next, we investigated if straightening occurs as early as the primary visual cortex (V1). We developed a novel computational tool to infer trajectories from neural populations and found robust straightening in V1 recordings from anesthetized macaques. Next, we explored the computational basis of V1 results with an image-computable model. We built a model to describe well-known computations of V1 cells and tested the model with the same movie stimuli. Model-predictions reveal that these computations only partially engage the mechanisms for straightening, revealing the involvement of more complex visual mechanisms. To further test our hypothesis, we asked if additional straightening occurs across the V1-V2 cascade. We recorded populations in areas V1 and V2 from awake fixating monkeys. Consistent with our hypothesis, we find incremental straightening between V1 and V2 elicited by the same natural movies. Together, we find collective evidence of neural straightening as an emergent property that contributes to perceptual straightening in a progressive manner starting from the early stages of vision

Download or read book The Primate Visual System written by Jon H. Kaas and published by CRC Press. This book was released on 2004 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discussing the neural behavior of visuomotor processing in the primate brain, this book synthesizes current knowledge on the anatomical and functional organization of the primate visual system and proposes new directions for research. It describes state-of-the-art methods for investigating the visual system and includes coverage of how the visual system is formed during development. Contributed by a multidisciplinary group of leading researchers, chapters consider a range of topics concerning various primates, including humans, and cover processing from the eye to neural codes for action, and from basic perception to memory.

Download or read book The Primate Visual System written by Jan Kremers and published by John Wiley & Sons. This book was released on 2005-12-13 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many recent developments in the field in recording, staining, genetic and stimulation techniques, in vivo, and in vitro have significantly increased the amount of available data on the primate visual system. Written with contributions from key neurobiologists in the field, The Primate Visual System will provide the reader with the latest developments, examining the structure, function and evolution of the primate visual system. The book takes a comparative approach as a basis for studying the physiological properties of primate vision and examines the phylogenetic relationship between the visual systems of different primate species. Taken from a neurobiologist’s perspective this book provides a unique approach to the study of primate vision as a basis for further study into the human visual system. Altogether an important overview of the structure, function and evolution of the primate visual system from a neurobiologist’s perspective, written specifically for higher level undergraduate and graduate students taking courses in neuroscience, physiology, optics/ visual science, as well as a valuable read to researchers new to the field.

Download or read book Natural Image Processing in the Primate Retina written by Nora Jane Brackbill and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The retina is the first stage of the visual system, where light is absorbed and encoded in the spikes of neurons. Information from roughly 100 million photoreceptors is compressed to the outputs of roughly 1 million neurons, called retinal ganglion cells, that make up the optic nerve. This is the brain's only source of visual information, yet how the retina uses this limited bandwidth is not well understood. This is particularly true for natural vision in primates, despite its relevance for human health applications, as retinal research is primarily done in non-primate species using targeted, artificial stimuli. Here, large-scale, multi-electrode recordings are used to investigate natural image processing in the primate retina through the complementary lenses of encoding, where computational models are used to predict the responses of RGCs to natural stimuli, and decoding, or reconstruction, where the stimulus is estimated from the RGC responses.

Download or read book Segmentation of Moving Images by the Primate Visual System written by Gene R. Stoner and published by . This book was released on 1992 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High level Visual Object Representation in Juvenile and Adult Primates written by Darren Allen Seibert and published by . This book was released on 2018 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite being reflexive, primate view invariant object recognition is a complex computational task. These computations are thought to reside in the ventral visual stream, specifically culminating in inferior temporal (IT) cortex. Recent research in machine learning has made great progress in modeling primate ventral visual stream computations. While the end result of current machine learning approaches produces models that are highly predictive of the adult state of the ventral stream, the learning approaches themselves are not biologically plausible, requiring tens of thousands to millions of human-labeled training points. Understanding primate visual development is therefore not only interesting from the perspective of neuroscience, but also has practical value in building more robust learning algorithms capable of functioning in domains where large amounts of human-labeled training information may be difficult or impossible to create. Better learning algorithms may also produce agents capable of adapting and behaving in the world not unlike humans. This thesis first describes work on predicting visual responses across the human ventral stream using convolutional neural networks (CNNs). We then describe a set of natural image statistics automatically incorporated into high-performing CNNs from supervised training-it is possible primate development incorporates these or similar natural image statistics into its synaptic strengths. Finally, we describe the first-large scale characterization of IT in 19-32 week old macaques. While we find longer response latencies in these younger animals, we do not find any differences in representation between adults and juveniles suggesting that, at 19-32 weeks of age, IT already supports robust object recognition consistent with adults. Our data provide an upper limit on the amount of training data needed to reach adult-level performance-approximately 2,800 hours of waking visual experience.

Download or read book Representation and Spatial Organization of Color and Orientation in Primate Primary Visual Cortex written by Anupam Kumar Garg and published by . This book was released on 2019 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under the longstanding model of the primate primary visual cortex (V1), color and form are processed by distinct neurons that are clustered according to cytochrome oxidase (CO) expression. Previous studies have demonstrated that there is not strict spatial segregation but have continued to support the model at single neuron level; previous studies have failed to identify neurons selective for both orientation and color that respond much more strongly to their preferred color (on an equiluminant background) than to achromatic stimuli. But previous studies have been limited in their spatial resolution and sampling of stimulus space, leaving several outstanding questions. We overcame limitations of previous studies by utilizing GCaMP6f 2-photon calcium imaging, which enabled long-term recording from large populations of neurons with single neuron resolution. We displayed a variety of stimuli, including equiluminant colored gratings and luminance-modulated achromatic gratings at a variety of orientations and spatial frequencies. We also conducted reverse correlation using cone-isolating gratings to map the cone inputs individual neurons. Finally, we aligned our calcium imaging results with intrinsic signal imaging (ISI) and postmortem histology to relate the responses of individual neurons to functional and anatomical markers, such as CO blobs. We reveal that nearly half (46.4%) of neurons in V1's superficial (cortico-cortical output) layers prefer colored to achromatic stimuli and nearly one-fifth (19.1%) respond more than twice as strongly to colored stimuli. Amongst these strongly color-preferring cells, the majority (11.6% of all cells) are also strongly orientation selective and located far from CO blobs, while the remaining color-preferring cells (7.5% of all cells) are poorly tuned for orientation and located close to CO blobs. We also reveal that cells are spatially organized according to preferred color and the sign of their dominant cone inputs. These findings demonstrate that color and form are jointly processed by a previously unreported population of neurons located predominantly in the interblobs of primate V1, indicating that early and integrated processing contributes to perception of visual objects. Observations that both cone inputs and preferred hues are systematically mapped within V1 are likely to reflect underlying organization of thalamic inputs and local circuits within V1.

Download or read book Computation and representation in the primate visual system written by Jeremy Freeman and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Representation of Three dimensional Space in Primate Visual Cortex written by Richard M. Jeo and published by . This book was released on 1998 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Representation of Three dimensional Objects in the Primate Visual System written by Jon Michael Pauls and published by . This book was released on 1997 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Visual Population Codes written by Nikolaus Kriegeskorte and published by MIT Press. This book was released on 2012 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: How visual content is represented in neuronal population codes and how to analyze such codes with multivariate techniques. Vision is a massively parallel computational process, in which the retinal image is transformed over a sequence of stages so as to emphasize behaviorally relevant information (such as object category and identity) and deemphasize other information (such as viewpoint and lighting). The processes behind vision operate by concurrent computation and message passing among neurons within a visual area and between different areas. The theoretical concept of "population code" encapsulates the idea that visual content is represented at each stage by the pattern of activity across the local population of neurons. Understanding visual population codes ultimately requires multichannel measurement and multivariate analysis of activity patterns. Over the past decade, the multivariate approach has gained significant momentum in vision research. Functional imaging and cell recording measure brain activity in fundamentally different ways, but they now use similar theoretical concepts and mathematical tools in their modeling and analyses. With a focus on the ventral processing stream thought to underlie object recognition, this book presents recent advances in our understanding of visual population codes, novel multivariate pattern-information analysis techniques, and the beginnings of a unified perspective for cell recording and functional imaging. It serves as an introduction, overview, and reference for scientists and students across disciplines who are interested in human and primate vision and, more generally, in understanding how the brain represents and processes information.

Download or read book Neural Representation of Complex Motion in the Primate Cortex written by Benedict Wild and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is concerned with how information about the environment is represented by neural activity in the primate brain. More specifically, it contains several studies that explore the representation of visual motion in the brains of humans and nonhuman primates through behavioral and physiological measures. The majority of this work is focused on the activity of individual neurons in the medial superior temporal area (MST) - a high-level, extrastriate area of the primate visual cortex. The first two studies provide an extensive review of the scientific literature on area MST. The ...

Download or read book On the Compact Representation of Image Sequences Partly Based on the Human Visual System written by Jacobus Adrianus Maria Stuifbergen and published by . This book was released on 1991 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Natural Image Statistics written by Aapo Hyvärinen and published by Springer Science & Business Media. This book was released on 2009-04-21 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aims and Scope This book is both an introductory textbook and a research monograph on modeling the statistical structure of natural images. In very simple terms, “natural images” are photographs of the typical environment where we live. In this book, their statistical structure is described using a number of statistical models whose parameters are estimated from image samples. Our main motivation for exploring natural image statistics is computational m- eling of biological visual systems. A theoretical framework which is gaining more and more support considers the properties of the visual system to be re?ections of the statistical structure of natural images because of evolutionary adaptation processes. Another motivation for natural image statistics research is in computer science and engineering, where it helps in development of better image processing and computer vision methods. While research on natural image statistics has been growing rapidly since the mid-1990s, no attempt has been made to cover the ?eld in a single book, providing a uni?ed view of the different models and approaches. This book attempts to do just that. Furthermore, our aim is to provide an accessible introduction to the ?eld for students in related disciplines.

Download or read book Primate Neuroethology written by Asif A. Ghazanfar and published by Oxford University Press, USA. This book was released on 2012-08-16 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited volume is the first of its kind to bridge the epistemological gap between primate ethologists and primate neurobiologists. Leading experts in several fields review work ranging from primate foraging behavior to the neurophysiology of motor control, from vocal communication to the functions of the auditory cortex.

Download or read book Understanding Vision written by Li Zhaoping and published by Oxford University Press, USA. This book was released on 2014 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vision science has grown hugely in the past decades, but there have been few books showing readers how to adopt a computional approach to understanding visual perception, along with the underlying mechanisms in the brain. This book explains the computational principles and models of biological visual processing, and in particular, primate vision.

Download or read book Principles of Frontal Lobe Function written by Donald T. Stuss and published by Oxford University Press. This book was released on 2002-06-27 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a comprehensive review of historical and current research on the function of the frontal lobes and frontal systems of the brain. The content spans frontal lobe functions from birth to old age, from biochemistry and anatomy to rehabilitation, and from normal to disrupted function. The book is intended to be a standard reference work on the frontal lobes for researchers, clinicians, and students in the field of neurology, neuroscience, psychiatry, psychology, and health care.