Coding of Multiple Sensory Parameters in Neural Ensembles

Coding of Multiple Sensory Parameters in Neural Ensembles PDF Author: Balasubramanian Girish
Publisher:
ISBN:
Category :
Languages : en
Pages : 296

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Coding of Multiple Sensory Parameters in Neural Ensembles

Coding of Multiple Sensory Parameters in Neural Ensembles PDF Author: Balasubramanian Girish
Publisher:
ISBN:
Category :
Languages : en
Pages : 296

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Book Description


Large-scale Neocortical Dynamics and Information Processing Underlying a Sensory Decision

Large-scale Neocortical Dynamics and Information Processing Underlying a Sensory Decision PDF Author: Mohammad Sadegh Ebrahimi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Sensory perception is fundamentally limited by the coding accuracy of sensory neural ensembles. Although a substantial body of work suggests that populations of sensory neurons exhibit correlated fluctuations that may bound the precision of neural coding, the extent to which these fluctuations extend across multiple cortical areas and interact with sensory coding during active animal behavior remain poorly understood. To examine the impact of correlated fluctuations on information coding and communication across sensory cortical areas, we imaged the Ca2+ activity of > 21,000 individual neurons across 11 neocortical areas in mice performing a Go/No-Go visual decision-making task. Multiple neocortical areas accurately encoded the visual stimulus, as well as the animal's decision to respond. Our analysis also revealed positively correlated noise fluctuations across neural populations in multiple neocortical areas. The mean strength of these noise correlations varied as a function of time across the visual stimulus presentation, delay, and response periods of our decision-making assay. Notably, sensory cortical neurons generally exhibited noise fluctuations that were more positively correlated at the start of visual stimulation, but then less so as a decision-making trial proceeded. Our results reveal that 60% of the total power of cortical variability stems from correlated fluctuations of neural populations spanning multiple distinct cortical areas. The strongest cortical fluctuation was a decision-coding activity mode that encompassed all brain areas under observation. We also found several fluctuation modes that encoded visual stimulus information but were shared across fewer brain areas. Overall, our analyses suggest that information regarding sensory stimuli and perceptual decisions are processed and shared between cortical areas through mutually non-interfering orthogonal channels. The timing of informative activity in these channels suggests that sensory information is first processed through intercommunications between multiple sensory areas, followed by a propagation of the final decision to all cortical areas involved.

Scale in Conscious Experience

Scale in Conscious Experience PDF Author: Joseph S. King
Publisher: Psychology Press
ISBN: 113499589X
Category : Psychology
Languages : en
Pages : 465

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Book Description
This volume is the result of the third Appalachian Conference on Behavioral Neurodynamics which focused on the problem of scale in conscious experience. Set against the philosophical view of "eliminative materialism," the purpose of this conference was to facilitate communication among investigators who approach the study of consciousness and conscious phenomena from a variety of analytical levels. One speculative outcome of the conference is that the columnar arrangement within primary sensory cortices may provide the local isolation necessary for nonlocal interactions to occur. In addition, the relationship between unit activity and field potentials within a circumscribed region of cortex may provide the other enigmatic aspect of neurophysiological nonlocality, namely, the common context in the macro scale. So instead of a problem looking for a solution, scale becomes a solution to a problem. Only further research will determine the utility of the ideas expressed here.

Experience-Dependent Refinement of Maps and Population Codes in Primary Somatosensory Cortex

Experience-Dependent Refinement of Maps and Population Codes in Primary Somatosensory Cortex PDF Author: Amy M LeMessurier
Publisher:
ISBN:
Category :
Languages : en
Pages : 68

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Book Description
Sensory experience can powerfully alter the spatial and temporal organization of population codes in the brain throughout an animal's lifetime. In this dissertation I focus on how changes in sensory experience, by learning or environmental enrichment, alter sensory map topography in rodent primary sensory cortex. In Chapter 1 I review recent advances in our understanding of how perceptual learning and related sensory manipulations shape the structure of primary sensory cortex maps across multiple sensory modalities. Classic studies of map plasticity in primary sensory cortex have shown that experience shapes sensory tuning in individual neurons and at the average population level. But effective neural population codes depend on more than just sensory tuning in individual cells averaged over time. With population calcium imaging, activity can be measured simultaneously in large ensembles of neurons during behavior. This and related techniques make it possible to study changes in the single-cell level organization of sensory coding, as well as high-dimensional codes that depend on the activity of large ensembles of cells, and which may change with behavioral context. Here I review recent population calcium imaging and recording studies that have characterized population codes in sensory cortex, and tracked how they change with sensory manipulations and training on perceptual learning tasks. These studies confirm average sensory tuning changes observed in earlier studies, but also reveal other features of plasticity, including sensory gain modulation, restructuring of firing correlations, and differential routing of information to output pathways. Unexpectedly strong day-to-day variation exists in single-neuron sensory tuning, which stabilizes during learning. These are novel dimensions of plasticity in sensory cortex, which refine population codes during learning, but whose mechanisms are unknown. Most of what is known about how sensory experience shapes maps is based on studies that have used robust sensory manipulations, such as deprivation, chronic over-stimulation, or explicit pairing of a sensory stimulus with a reward or punishment, as in the studies discussed in Chapter 1. However, much less is known about how maps are refined by natural behavior-driven sensory experience. To understand how natural tactile experience influences map development, We studied the effects of tactile enrichment on the organization of the whisker map in mouse primary somatosensory cortex (S1), which is highly plastic throughout life and which contains an anatomically well-defined map of the whiskers. Mice were raised with enrichment (EN) or normal housing (CT) beginning at weaning (P21). We focused our study on Layer 2/3 (L2/3), which is particularly plastic and which has a “salt-and-pepper” organization of whisker tuning, and Layer 4 (L4), which contains the anatomical map of the whiskers. The genetically-encoded calcium indicator GCaMP6s was expressed virally in L2/3 or L4 excitatory cells using cell-type and layer-specific Cre mice. At P62 ± 13 days, we measured neuronal responses to 9 whiskers using 2-photon imaging through a chronic cranial window. After imaging was complete, cells were localized relative to anatomical barrel column boundaries corresponding to the whiskers in the stimulus set. Within a single anatomical column in both L2/3 and L4 excitatory cells, cells were heterogeneously tuned to different whiskers. Enrichment increased somatotopic precision (the fraction of cells within a certain radius that were anatomically tuned) in both layers near the centers of anatomical columns. Enrichment also sharpened whisker tuning curves in both layers, and essentially increased signal-to-noise of whisker coding in L2/3 by decreasing spontaneous activity while maintaining response magnitudes for columnar whiskers. In L2/3, point representations (the density and spatial spread of neurons responding to a whisker) were sharpened by increased whisker responses among cells located close to column centers. To study the impact of enrichment on the spatial and temporal structure of population coding, we compared pairwise noise and signal correlations in whisker-evoked activity within each column. In L2/3, signal correlations – which reflect overall tuning similarity – were similar in EN and CT for pairs within columns, though signal correlations were higher in EN for pairs located further apart. However, for pairs of neurons located across column boundaries but at similar distances, signal correlations were dramatically decreased in EN, while comparable to in-column levels in CT. In both groups, noise correlations – which reflect shared trial-by-trial variability that is independent of the stimulus – decreased sharply with distance between neurons. For pairs of cells across column boundaries in CT mice, signal and noise correlations exhibited the same relationships with inter-cell distance as within column pairs; however, In EN mice, cross-column signal and noise correlations were substantially reduced compared to in-column pairs. Essentially, enrichment induced reorganization of functional correlations along anatomical column boundaries. This suggests that enrichment may selectively alter connectivity and/or shared synaptic input according to column boundaries. These findings demonstrate a strong impact of juvenile sensory experience on functional columnar topography and organization in S1, and indicate that enrichment sharpens whisker representations at the population level in L2/3.

Methods for NEURAL ENSEMBLE RECORDINGS

Methods for NEURAL ENSEMBLE RECORDINGS PDF Author: Miguel A. L. Nicolelis
Publisher: CRC Press
ISBN: 9781420048254
Category : Science
Languages : en
Pages : 288

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Book Description
Neuroscientists have long recognized the importance of understanding the underlying principles of information processing by large populations of neurons. Methods for Neural Ensemble Recordings explores methods for using electrophysiological techniques for monitoring the concurrent activity of ensembles of single neurons. Since current methods allow one to simultaneously record the extracellular activity of up to 100-150 neurons for days or even weeks, neural ensemble recordings have been used to address long-standing issues in development, learning, memory, sensorimotor integration, sensory information processing, and neuronal plasticity. EXAMINES THE MANY POSSIBLE APPLICATIONS FOR THIS REVOLUTIONARY METHOD Each chapter offers a step-by-step description for the implementation of a particular technique or experimental paradigm employing simultaneous multiple electrode recordings. The techniques described can be used in applications that impact a large group of life scientists, including: drug screening (pharmacology) in both in vitro and in vivo preparations developmental studies and studies of neuronal plasticity chronic monitoring of neuronal function in behavioral studies physiological monitoring of neuronal activity in cell cultures and brain slices physiological monitoring of neuronal activity in neurons trafected with genetic vectors chronic monitoring of physiological changes in populations of neurons during learning of new sensorimotor and cognitive tasks

Methods for Neural Ensemble Recordings

Methods for Neural Ensemble Recordings PDF Author: Miguel A. L. Nicolelis
Publisher: CRC Press
ISBN: 142000641X
Category : Medical
Languages : en
Pages : 308

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Book Description
Extensively updated and expanded, this second edition of a bestseller distills the current state-of-the-science and provides the nuts and bolts foundation of the methods involved in this rapidly growing science. With contributions from pioneering researchers, it includes microwire array design for chronic neural recordings, new surgical techniques for chronic implantation, microelectrode microstimulation of brain tissue, multielectrode recordings in the somatosensory system and during learning, as well as recordings from the central gustatory-reward pathways. It explores the use of Brain-Machine Interface to restore neurological function and proposes conceptual and technical approaches to human neural ensemble recordings in the future.

Statistical analysis of multi-cell recordings: linking population coding models to experimental data

Statistical analysis of multi-cell recordings: linking population coding models to experimental data PDF Author: Matthias Bethge
Publisher: Frontiers E-books
ISBN: 2889190129
Category :
Languages : en
Pages : 209

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Book Description
Modern recording techniques such as multi-electrode arrays and 2-photon imaging are capable of simultaneously monitoring the activity of large neuronal ensembles at single cell resolution. This makes it possible to study the dynamics of neural populations of considerable size, and to gain insights into their computations and functional organization. The key challenge with multi-electrode recordings is their high-dimensional nature. Understanding this kind of data requires powerful statistical techniques for capturing the structure of the neural population responses and their relation with external stimuli or behavioral observations. Contributions to this Research Topic should advance statistical modeling of neural populations. Questions of particular interest include: 1. What classes of statistical methods are most useful for modeling population activity? 2. What are the main limitations of current approaches, and what can be done to overcome them? 3. How can statistical methods be used to empirically test existing models of (probabilistic) population coding? 4. What role can statistical methods play in formulating novel hypotheses about the principles of information processing in neural populations? This Research Topic is connected to a one day workshop at the Computational Neuroscience Meeting 2009 in Berlin (http://www.cnsorg.org/2009/workshops.shtml and http://www.kyb.tuebingen.mpg.de/bethge/workshops/cns2009/)

Time and the Brain

Time and the Brain PDF Author: Robert Miller
Publisher: CRC Press
ISBN: 0203304578
Category : Science
Languages : en
Pages : 515

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Book Description
Since the days of Galileo, time has been a fundamental variable in scientific attempts to understand the natural world. Once the first recordings of electrical activity in the brain had been made, it became clear that electrical signals from the brain consist of very complex temporal patterns. This can now be demonstrated by recordings at the single unit level and by electroencephalography (EEG). Time and the Brain explores modern approaches to these temporal aspects of electrical brain activity. The temporal structure as revealed from trains of impulses from single nerve cells and from EEG recordings are discussed in depth together with an exploration of correlations with behaviour and psychology. The single cell and EEG approaches often tend to be segregated as the research occurs in laboratories in different parts of the world. By bringing together modern information acquired using both methods it is hoped that they can become better integrated as complimentary windows on the information processing achieved by the brain.

The Neural Bases of Multisensory Processes

The Neural Bases of Multisensory Processes PDF Author: Micah M. Murray
Publisher: CRC Press
ISBN: 1439812179
Category : Science
Languages : en
Pages : 800

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Book Description
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.

Spikes

Spikes PDF Author: Fred Rieke
Publisher: MIT Press (MA)
ISBN: 9780262181747
Category : Action potentials (Electrophysiology)
Languages : en
Pages : 418

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Book Description
Intended for neurobiologists with an interest in mathematical analysis of neural data as well as the growing number of physicists and mathematicians interested in information processing by "real" nervous systems, Spikes provides a self-contained review of relevant concepts in information theory and statistical decision theory.