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Conference on Fluctuations and Noise in Biological, Biophysical, and Biomedical Systems III

作者： McDonnell, MD Stocks, NG Pearce, CEM Abbott, D Univ Adelaide Ctr Biomed Engn Adelaide SA 5005 Australia

ISBN: (纸本)0819458368

It is shown that Suprathreshold Stochastic Resonance (SSR) is effectively a way of using noise to perform quantization or lossy signal compression with a population of identical threshold-based devices. Quantization of an analog signal is a fundamental requirement for its efficient storage or compression in a digital system. This process will always result in a loss of quality, known as distortion, in a reproduction of the original signal. The distortion can be decreased by increasing the number of states available for encoding the signal (measured by the rate, or mutual information). Hence, designing a quantizer requires a tradeoff between distortion and rate. Quantization theory has recently been applied to the analysis of neural coding and here we examine the possibility that SSR is a possible mechanism used by populations of sensory neurons to quantize signals. In particular, we analyze the rate-distortion performance of SSR for a range of input SNR's and show that both the optimal distortion and optimal rate occurs for an input SNR of about 0 dB, which is a biologically plausible situation. Furthermore, we relax the constraint that all thresholds are identical, and find the optimal threshold values for a range of input SNRs. We find that for sufficiently small input SNRs, the optimal quantizer is one in which all thresholds are identical, that is, the SSR situation is optimal in this case.

关键词： suprathreshold stochastic resonance stochastic resonance quantization rate-distortion Analog to Digital Conversion noise neural coding dithering lossy source coding compression

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Approaches to Information-Theoretic Analysis of neural Activity

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Biological Theory 2006年第3期1卷 302-316页

作者： Victor, Jonathan D. Department of Neurology and Neuroscience Weill Medical College of Cornell University New York NY United States

Understanding how neurons represent, process, and manipulate information is one of the main goals of neuroscience. These issues are fundamentally abstract, and information theory plays a key role in formalizing and addressing them. However, application of information theory to experimental data is fraught with many challenges. Meeting these challenges has led to a variety of innovative analytical techniques, with complementary domains of applicability, assumptions, and goals. © 2006, Konrad Lorenz Institute for Evolution and Cognition Research.

关键词： direct method information theory metric space method neural coding sensory spike trains systems

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neural Representation of Hedonic Tastes in the Ventral Pallidum

Neural Representation of Hedonic Tastes in the Ventral Palli...

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作者： Itoga, Christy A University of Michigan

学位级别：doctor

The overall goal of this thesis was to investigate how the ventral pallidum tracks experimentally-induced changes in the hedonic value of tastes. Taste reactions allows us to measure how 'liked' or 'disliked' a taste is by a rat. These reactions are not purely reflexive as they are altered when circumstances change: hunger can increase and satiety can decrease the tastiness of foods (Berridge 1996) and a salt appetite can make a normally 'disliked' salt solution 'liked' (Berridge et al. 1984, Schulkin 1991). Therefore taste reactions reflect the palatability of tastes. Understanding how the reward pathway tracks changes in the hedonic value of tastes may elucidate how neural coding is affected in disorders such as drug addiction and obesity. The first project investigated how neurons in the ventral pallidum (VP) track changes in hedonic value of a sweet taste by a conditioned taste aversion. When a taste changed from 'liked' to 'disliked', the predominant VP response also changed: taste responsive VP cells tastes typically increase firing rate in response to 'liked' tastes whereas the hedonically devalued taste typically triggered a decrease in firing rate. The second project compared the effects of dopamine and opioid modulation of 'liked', relatively neutral, and 'disliked' taste stimuli. We found that opioid modulation enhanced the hedonic value of quinine (which is normally 'disliked'), but that only morphine resulted in a VP population response that mirrored the hedonic value of the tastes. The third project tested the effects of dopamine and opioid modulation on the hedonic value of a pair of cues (water infusions) and reward (a sucrose infusion). Overall, the cues did increase in hedonic value via association with reward, and the VP reflected the similarity in hedonic value between the cues and reward by responding similarly to cues and reward, under most drug conditions. Amphetamine decreased the proportion of units that responded to the first cue with an in

关键词： Ventral Pallidum neural Responses neural coding Hedonic Value Hedonia Taste Neurosciences Health Sciences

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Retinal coding: Encoding and Decoding in Natural Scenes

Retinal Coding: Encoding and Decoding in Natural Scenes

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作者： Hoshal, Benjamin The University of Chicago

学位级别：Ph.D., Doctor of Philosophy

Everything that the brain sees must first be encoded by the retina, which maintains a reliable representation of the visual world in many different, complex natural scenes while also adapting to stimulus changes. Decomposing the population code into independent and cell-cell interactions reveals how broad scene structure is encoded in the adapted retinal output. By recording from the same retina while presenting many different natural movies, we see that the population structure, characterized by strong interactions, is consistent across both natural and synthetic stimuli. We show that these interaction contribute to encoding scene identity, and demonstrate that leveraging this underlying interaction network improves scene decoding. This population structure likely arises in part from shared bipolar cell input as well as from gap junctions between retinal ganglion cells and amacrine cells. Separately, we use a task-agnostic deep architecture, and encoder-decoder, to model the retinal encoding process and characterize its representation of ‘time in the natural scene’ in a compressed latent space. In this end-to-end training, an encoder learns a compressed latent representation from the retinal ganglion cell population, while a decoder samples from this latent space to to generate the appropriate future scene frame. By comparing latent representation of retinal activity from three natural movies, we find that the retina has a generalizable encoding for time in natural scenes, and that this encoding can be used to decode future frames with up to 17ms resolution. Lastly, we explore methods to efficiently scale small population models up to a large population using an aggregate approach.

关键词： Natural scenes neural coding neural computation Population code Retina

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A MULTI-SPIKE APPROACH FOR ROBUST SOUND RECOGNITION 44

A MULTI-SPIKE APPROACH FOR ROBUST SOUND RECOGNITION

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44th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Yu, Qiang Yao, Yanli Wang, Longbiao Tang, Huajin Dang, Jianwu Tianjin Univ Tianjin Key Lab Cognit Comp & Applicat Coll Intelligence & Comp Tianjin Peoples R China Sichuan Univ Coll Comp Sci Chengdu Sichuan Peoples R China

ISBN: (纸本)9781479981311

The extraordinary performance of the brain on various cognitive tasks motivates the design of a biologically plausible system for the challenging task of environmental sound recognition. In this paper, we propose a novel approach based on multi-spike learning and key-point encoding. Our encoding extracts local temporal and spectral information from the sound and converts it into spatiotemporal spike pattern, which is further learned by the following spiking neural networks. Our experiments demonstrate the robustness and effectiveness of our approach across a variety of noise conditions, outperforming other conventional baseline methods in both mismatched and multi-condition scenarios.

关键词： Sound recognition neural coding multi-spike learning neuromorphic computing

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Effects of tACS-Like Electrical Stimulation on Correlated Firing of Retinal Ganglion Cells: Part III

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EYE AND BRAIN 2022年 14卷 1-15页

作者： Amthor, Franklin R. Strang, Christianne E. Univ Alabama Birmingham Dept Psychol 1300 Univ Blvd Birmingham AL 35294 USA

Purpose: Transcranial alternating current stimulation (tACS) is a stimulation protocol used for learning enhancement and mitigation of cognitive dysfunction. Correlated firing has been postulated to be a meta-code that links neuronal spike responses associated with a single entity and may be an important component of high-level cognitive functions. Thus, changes in the covariance firing structure of CNS neurons such as retinal ganglion cells are one potential mechanism by which tACS can exert its effects. Materials and Methods: We used microelectrode arrays to record light-evoked spike responses of 24 retinal ganglion cells in 7 rabbit eyecup preparations and analyzed the covariance between 30 pairs of neighboring retinal ganglion cells before, during, and after 10-minute application of alternating currents of 1 microampere at 10 or 20 Hz. Results: tACS stimulation significantly changed the covariance structure of correlated firing in 60% of simultaneously recorded retinal ganglion cells. Application of tACS in the retinal preparation increased cross-covariance in 26% of cell pairs, an effect usually associated with increased light-evoked ganglion cell firing. tACS associated decreases in cross-covariance occurred in 37% of cell pairs. Increased covariance was more common in response to the first, 10-minute application of tACS in isolated retina preparation. Changes in covariance were rare after repeated stimulation, and more likely to result in decreased covariance. Conclusion: Retinal ganglion cell correlated firing is modulated by 1 microampere tACS currents showing that electrical stimulation can significantly and persistently change the structure of the correlated firing of simultaneously recorded rabbit retinal ganglion cells.

关键词： retina tACS mechanisms CNS in vitro model neural coding neuromodulation correlated firing cross covariance

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Periodic neural codes and sound localization in barn owls

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INVOLVE, A JOURNAL OF MATHEMATICS 2022年第1期15卷 1-37页

作者： Brown, Lindsey S. Curto, Carina Princeton Univ Princeton Neurosci Inst Princeton NJ 08544 USA Penn State Univ Dept Math State Coll PA USA

Inspired by the sound localization system of the barn owl, we define a new class of neural codes, called periodic codes, and study their basic properties. Periodic codes are binary codes with a special patterned form that reflects the periodicity of the stimulus. Because these codes can be used by the owl to localize sounds within a convex set of angles, we investigate whether they are examples of convex codes, which have previously been studied for hippocampal place cells. We find that periodic codes are typically not convex, but can be completed to convex codes in the presence of noise. We introduce the convex closure and Hamming distance completion as ways of adding codewords to make a code convex, and describe the convex closure of a periodic code. We also find that the probability of the convex closure arising stochastically is greater for sparser codes. Finally, we provide an algebraic method using the neural ideal to detect if a code is periodic. We find that properties of periodic codes help to explain several aspects of the behavior observed in the sound localization system of the barn owl, including common errors in localizing pure tones.

关键词： neural coding convex codes periodic codes sound localization neural ideal

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A neural Assembly-Based View on Word Production: The Bilingual Test Case

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LANGUAGE LEARNING 2016年第Sup2期66卷 92-131页

作者： Strijkers, Kristof Lab Parole & Langage Aix En Provence France

I will propose a tentative framework of how words in two languages could be organized in the cerebral cortex based on neural assembly theory, according to which neurons that fire synchronously are bound into large-scale distributed functional units (assemblies), which represent a mental event as a whole ("gestalt"). For language this means a word is engendered by widely distributed cell assemblies in which the different linguistic constituents are grouped together in action-perception circuits and become activated in parallel. In this article I will discuss the advantages of assembly coding over the traditional hierarchical convergence scheme. Recent evidence from language comprehension and production supporting the notion of neural assemblies representing words are discussed and a spatiotemporal model for word production based on this concept is presented. Finally, I will show how this view may be generalized to bilingualism and explain mechanistically some key phenomena in the literature.

关键词： language production bilingualism neural coding binding problems cell assemblies

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In vitro experiments of information transmission in a frog sciatic nerve

In vitro experiments of information transmission in a frog s...

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IEEE International Workshop on Medical Measurement and Applications

作者： Hannula, M. Alasaarela, E. Tikkanen, J. Makynen, A. Myllyla, R. Univ Oulu Dept Elect & Informat Engn LinanmaaPOB 4500 FIN-90014 Oulu Finland

ISBN: (纸本)9781424402526

The peripheral nervous system consists of a large number of axons which transmit information from peripheral receptors to the central nervous system or from central nervous system to the muscles and glands in the periphery. The theoretical maximum information transmission rate in those axons has been proposed to be much, even hundreds of bits per second in one axon. But, what are the information rates in practice, when the noise and other distorting factors are present in transmission, is not accurately known. To evaluate the practical information transmission rate in the peripheral nerves an in vitro information transmission study was done by using a frog sciatic nerve as a channel in artificial information transmission from one computer to another in laboratory environment. The highest achieved non-erroneous information transmission rate was 164 bit/s and the highest rate, including some errors, was 228 bit/s.

关键词： information transmission capacity neural coding action potential

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Effects of tACS-Like Electrical Stimulation on On-Center Retinal Ganglion Cells: Part I

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EYE AND BRAIN 2021年 13卷 175-192页

作者： Amthor, Franklin R. Strang, Christianne E. Univ Alabama Birmingham Dept Psychol 1300 Univ Blvd Birmingham AL 35294 USA

Purpose: Electrical stimulation of the human central nervous system via surface electrodes has been used for both learning enhancement and the amelioration of neurodegenerative or psychiatric disorders. However, data are sparse on how such electrical stimulation affects neural circuits at the cellular level. This study assessed the effects of tACS-like currents at 10 Hz on On-center retinal ganglion cell responsiveness, using the rabbit retina eyecup preparation as a model for central nervous system effects. Methods: We made extracellular recordings of light-evoked spike responses in different classes of On-center retinal ganglion cells before, during and after brief applications of 1 microampere alternating currents using single electrodes and microelectrode arrays. Results: tACS-like currents (tACS) of 1 microampere produced effects on On-center ganglion cell response profiles immediately after initiation or cessation of tACS, without driving phase-locked firing in the absence of light stimuli. tACS affected the initial transient responses to light stimulation for all cells, sustained response components (if any) more strongly for sustained cells, and the center-surround balance more strongly for transient cells. Conclusion: tACS sculpted light-evoked responses that lasted for one or more hours after cessation of current without, itself, directly inducing significant firing changes. Functionally, tACS effects could result in effects on contrast thresholds for both broad classes of cells, but because tACs differentially affects the center-surround balance of transient On-center cells, there may be greater effects on the spatial resolution and gain. The isolated retina appears to be a useful model to understand tACS actions at the neuronal level.

关键词： retina tACS mechanisms CNS in vitro model neural coding neuromodulation

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