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Reading Between the Spikes of the Hypothalamic neural code

JOURNAL OF NEUROENDOCRINOLOGY 2010年第12期22卷 1239-1250页

作者： Bhumbra, G. S. Dyball, R. E. J. UCL Dept Neurosci Physiol & Pharmacol London WC1E 6BT England Univ Cambridge Dept Physiol Dev & Neurosci Cambridge England

Reading the spike coding of hypothalamic neurones presents a considerable challenge because they exhibit highly irregular firing patterns. Electrophysiologists working in the motor and sensory systems, in which neurones fire more regularly, have devised satisfactory methods to describe the firing of cells, although the statistical assumptions that underlie the methods do not apply to hypothalamic neurones. Measurement of neural activity is nevertheless vital to characterise the activity of neuroendocrine cells. It has thus become necessary to develop methods suitable for the analysis of the highly irregular spike discharge patterns of both spontaneous and stimulus-evoked firing of hypothalamic neurones. We review techniques used to meet this challenge and demonstrate their considerable capacity to address important physiological questions. We also introduce a novel approach for valid statistical estimation of the information conveyed by the response of a single neurone to a periodic stimulus. The approach demonstrated significant diurnal rhythms of synaptic connectivity between hypothalamic nuclei.

关键词： neural code information theory hypothalamus

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The neural code for taste in the brain stem: Response profiles

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PHYSIOLOGY & BEHAVIOR 2000年第1-2期69卷 87-96页

作者： Di Lorenzo, PM SUNY Binghamton Dept Psychol Binghamton NY 13902 USA

In the study of the neural code for taste, two theories have dominated the literature: the across neuron pattern (ANP), and the labeled line theories. Both of these theories are based on the observations that taste cells are multisensitive across a variety of different taste stimuli. Given a fixed array of taste stimuli, a cell's particular set of sensitivities defines its response profile. The characteristics of response profiles are the basis of both major theories of coding. In reviewing the literature, it is apparent that response profiles are an expression of a complex interplay of excitatory and inhibitory inputs that derive from cells with a wide variety of sensitivity patterns. These observations suggest that, in the absence of inhibition, taste cells might be potentially responsive to all taste stimuli. Several studies also suggest that response profiles can be influenced by the taste context, defined as the taste stimulus presented just before or simultaneously with another, under which they are recorded. A theory, called dynamic coding, was proposed to account for context dependency of taste response profiles. In this theory, those cells that are unaffected by taste context would provide the signal, i.e., the information-containing portion of the ANP, and those cells whose responses are context dependent would provide noise, i.e., less stimulus specific information. When singular taste stimuli are presented, noise cells would provide amplification of the signal, and when complex mixtures are presented, the responses of the noise cells would be suppressed (depending on the particular combination of tastants), and the ratio of signal to noise would be enhanced. (C) 2000 Elsevier Science Inc. All rights reserved.

关键词： neural code taste brain stem response profiles

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Navigating the neural Space in Search of the neural code

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NEURON 2017年第5期93卷 1003-1014页

作者： Jazayeri, Mehrdad Afraz, Arash MIT Dept Brain & Cognit Sci McGovern Inst Brain Res E25-618 Cambridge MA 02139 USA

The advent of powerful perturbation tools, such as optogenetics, has created new frontiers for probing causal dependencies in neural and behavioral states. These approaches have significantly enhanced the ability to characterize the contribution of different cells and circuits to neural function in health and disease. They have shifted the emphasis of research toward causal interrogations and increased the demand for more precise and powerful tools to control and manipulate neural activity. Here, we clarify the conditions under which measurements and perturbations support causal inferences. We note that the brain functions at multiple scales and that causal dependencies may be best inferred with perturbation tools that interface with the system at the appropriate scale. Finally, we develop a geometric framework to facilitate the interpretation of causal experiments when brain perturbations do or do not respect the intrinsic patterns of brain activity. We describe the challenges and opportunities of applying perturbations in the presence of dynamics, and we close with a general perspective on navigating the activity space of neurons in the search for neural codes.

关键词： neural code correlation causation perturbation behavior neural manifold

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A Tradeoff in the neural code across Regions and Species

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CELL 2019年第3期176卷 597-+页

作者： Pryluk, Raviv Kfir, Yoav Gelbard-Sagiv, Hagar Fried, Itzhak Paz, Rony Weizmann Inst Sci Dept Neurobiol Rehovot Israel Tel Aviv Univ Dept Physiol & Pharmacol Sackler Fac Med Tel Aviv Israel Univ Calif Los Angeles Dept Neurosurg Los Angeles CA USA Tel Aviv Univ Sackler Fac Med Dept Neurol & Neurosurg Tel Aviv Israel Tel Aviv Med Ctr & Sch Med Funct Neurosurg Unit Tel Aviv Israel

Many evolutionary years separate humans and macaques, and although the amygdala and cingulate cortex evolved to enable emotion and cognition in both, an evident functional gap exists. Although they were traditionally attributed to differential neuroanatomy, functional differences might also arise from coding mechanisms. Here we find that human neurons better utilize information capacity (efficient coding) than macaque neurons in both regions, and that cingulate neurons are more efficient than amygdala neurons in both species. In contrast, we find more overlap in the neural vocabulary and more synchronized activity (robustness coding) in monkeys in both regions and in the amygdala of both species. Our findings demonstrate a tradeoff between robustness and efficiency across species and regions. We suggest that this tradeoff can contribute to differential cognitive functions between species and underlie the complementary roles of the amygdala and the cingulate cortex. In turn, it can contribute to fragility underlying human psychopathologies.

关键词： amygdala cingulate-cortex neural code primates evolution anxiety/mood disorders cognition efficiency robustness

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Multisynaptic activity in a pyramidal neuron model and neural code

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BIOSYSTEMS 2006年第1-3期86卷 18-26页

作者： Ventriglia, Francesco Di Maio, Vito CNR Ist Cibernet E Caianiello I-80078 Pozzuoli NA Italy

The highly irregular firing of mammalian cortical pyramidal neurons is one of the most striking observation of the brain activity. This result affects greatly the discussion on the neural code, i.e. how the brain codes information transmitted along the different cortical stages. In fact it seems to be in favor of one of the two main hypotheses about this issue, named the rate code. But the supporters of the contrasting hypothesis, the temporal code, consider this evidence inconclusive. We discuss here a leaky integrate-and-fire model of a hippocampal pyramidal neuron intended to be biologically sound to investigate the genesis of the irregular pyramidal firing and to give useful information about the coding problem. To this aim, the complete set of excitatory and inhibitory synapses impinging on such a neuron has been taken into account. The firing activity of the neuron model has been studied by computer simulation both in basic conditions and allowing brief periods of over-stimulation in specific regions of its synaptic constellation. Our results show neuronal firing conditions similar to those observed in experimental investigations on pyramidal cortical neurons. In particular, the variation coefficient (CV) computed from the inter-spike intervals (ISIs) in our simulations for basic conditions is close to the unity as that computed from experimental data. Our simulation shows also different behaviors in firing sequences for different frequencies of stimulation. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

关键词： pyramidal neuron irregular firing neural code computer simulation synaptic constellation

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MODEL OF neural code FOR TASTE QUALITY

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PHYSIOLOGY & BEHAVIOR 1972年第4期9卷 559-563页

作者： YAMAMOTO, T KAWAMURA, Y OSAKA UNIV DENT SCHDEPT ORAL PHYSIOLKITAKUOSAKAJAPAN

The 80 chorda tympani single fibers were selected following the rate of appearance of each response type of units for four taste stimuli in arbitrarily selected 400 fibers in the rat. These 80 fibers were distributed in the matrix with 80 squares in order of the units with sucrose, NaCl, acid and quinine sensitivities from left to right, and also with the intention to make the monotonic function for each quality accomplished by putting the units in appropriate columns. Thus, we could satisfactorily demonstrate the possibility to represent the pictures of across fiber response patterns quantitatively as bar graphs in the matrix. As the matrix patterns for 0.01 M to 0.1 M NaCl were almost the same, the matrix pattern is considered to represent only the taste quality. The matrix patterns obtained for DL-alanine, Na-saccharin, MSG and AgNO 3 were well consistent with results of electrophysiological, behavioral and psychophysical studies.

关键词： neural code Taste quality Chorda tympani responses Matrix pattern

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Image Compression based on Neuroscience Models: Rate-Distortion performance of the neural code

Image Compression based on Neuroscience Models: Rate-Distort...

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Data Compression Conference (DCC)

作者： Doutsi, Effrosyni Tsakalides, Panagiotis Fdn Res & Technol Hellas Iraklion Greece Univ Crete Iraklion Greece

ISBN: (纸本)9781728164571

Image compression still remains one of the most challenging scientific fields as it is widely used in almost every kind of application. To design groundbreaking architectures the image processing community concentrated at first on visual perception. However, understanding how the visual system senses the semantics of the visual scene is still a big issue. Recently, a neuro-inspired compression (NICE) system was introduced, trying to encode the visual information by mimicking the firing mechanisms of neurons. The performance of this system was promising but inefficient when opposed to the JPEG standard. In this work, we aim at improving the architecture design of the NICE system. Thus, we propose 3 different architectures and we show that the quality of the reconstruction is substantially enhanced. In addition, the NICE system outperforms the JPEG standard according to the assessment of two full-reference metrics;the peak signal-to-noise ratio (PSNR) and the structure similarity index measure (SSIM), except for very low bits per pixel values. © 2020 IEEE.

关键词： Full reference image quality assessment Image compression neural code Neuro inspired compression

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Burst firing is a neural code in an insect auditory system

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FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2008年第2008期2卷 3-3页

作者： Eyherabide, Hugo G. Rokem, Ariel Herz, Andreas V. M. Samengo, Ines Ctr Atom Bariloche RA-8400 San Carlos De Bariloche Rio Negro Argentina Inst Balseiro San Carlos De Bariloche Rio Negro Argentina Humboldt Univ Dept Biol Inst Theoret Biol D-1040 Berlin Germany Bernstein Ctr Computat Neurosci Berlin Germany

Various classes of neurons alternate between high-frequency discharges and silent intervals. This phenomenon is called burst firing. To analyze burst activity in an insect system, grasshopper auditory receptor neurons were recorded in vivo for several distinct stimulus types. The experimental data show that both burst probability and burst characteristics are strongly influenced by temporal modulations of the acoustic stimulus. The tendency to burst, hence, is not only determined by cell-intrinsic processes, but also by their interaction with the stimulus time course. We study this interaction quantitatively and observe that bursts containing a certain number of spikes occur shortly after stimulus deflections of specific intensity and duration. Our findings suggest a sparse neural code where information about the stimulus is represented by the number of spikes per burst, irrespective of the detailed interspike-interval structure within a burst. This compact representation cannot be interpreted as a firing-rate code. An information-theoretical analysis reveals that the number of spikes per burst reliably conveys information about the amplitude and duration of sound transients, whereas their time of occurrence is reflected by the burst onset time. The investigated neurons encode almost half of the total transmitted information in burst activity.

关键词： burst spiking neural code sensory encoding information theory auditory receptor

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Spike timing – an incomplete description of neural code

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BMC Neurosci 2007年第SUPPL 2期8卷 P149-P149页

作者： Dorian Aur Christopher I Connolly Mandar S Jog Department of Clinical Neurological Sciences Movement Disorders Program London Ontario Canada SRI International Menlo Park CA USA

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neural Chronos ODE: Modelling bidirectional temporal patterns in time-series data

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EXPERT SYSTEMS WITH APPLICATIONS 2025年 273卷

作者： Coelho, C. Costa, M. Fernanda P. Ferras, L. L. Univ Minho Ctr Math CMAT P-4710057 Braga Portugal Univ Porto Fac Engn Ctr Estudos Fenomenos Transporte P-4200465 Porto Portugal Univ Porto Fac Engn ALiCE P-4200465 Porto Portugal

This work introduces neural Chronos Ordinary Differential Equations (neural code), a deep neural network architecture that fits a continuous-time ODE dynamics for predicting the chronology of a system both forward and backward in time. To train the model, we solve the ODE as an initial value problem and a final value problem, similar to neural ODEs. We also explore two approaches to combining neural code with Recurrent neural Networks by replacing neural ODE with neural code (code-RNN), and incorporating a bidirectional RNN for full information flow in both time directions (code-BiRNN). Variants with other update cells namely GRU and LSTM are also considered and referred to as: code-GRU, code-BiGRU, code-LSTM, code-BiLSTM. Experimental results demonstrate that neural code outperforms neural ODE in learning the dynamics of a spiral forward and backward in time, even with sparser data. We also compare the performance of code-RNN/GRU/-LSTM and code-BiRNN/-BiGRU/-BiLSTM against ODE-RNN/-GRU/-LSTM on three real-life time-series data tasks: imputation of missing data for lower and higher dimensional data, and forward and backward extrapolation with shorter and longer time horizons. Our findings show that the proposed architectures converge faster, with code-BiRNN/-BiGRU/-BiLSTM consistently outperforming the other architectures on all tasks, achieving a notably smaller mean squared error-often reduced by up to an order of magnitude.

关键词： neural Networks Time-series neural ODE Forecasting future Unveiling past neural code Numerical methods

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