This paper investigates the dynamical and control properties of a discrete spiking neural network model with axonal delays. After examining contemporary work on spike timing as a mechanism for neural coding, we introd...
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ISBN:
(纸本)9781450311779
This paper investigates the dynamical and control properties of a discrete spiking neural network model with axonal delays. After examining contemporary work on spike timing as a mechanism for neural coding, we introduce a simple axonal delay network model which, via coincidence detection, demonstrates the presence of biologically observed regimes such as sustained firing and the emergence of synchrony. We establish delay criteria allowing for the classification of three distinct regimes including global synchrony, complex firing, and dissipation. We then proceed to test this model in a robot light seeking task. Results show that evolving network delays is sufficient for solving the task. We conclude by hypothesizing that global synchronous firing is more suited to reactive behaviours while complex firing patterns may serve as an organizing mechanism for more indirect processing.
This paper aims to build an image coding system based on a model of the mammalian retina. The retina is the light-sensitive layer of tissue located on the inner coat of the eye and it is responsible for vision. Inspir...
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ISBN:
(纸本)9781479970612
This paper aims to build an image coding system based on a model of the mammalian retina. The retina is the light-sensitive layer of tissue located on the inner coat of the eye and it is responsible for vision. Inspired by the way the retina handles and compresses visual information and based on previous studies we aim to build and analytically study a retinal-inspired image quantizer, based on the Leaky Integrate-and-Fire (LIF) model, a neural model approximating the behavior of the ganglion cells of the Ganglionic retinal layer that is responsible for visual data compression. In order to have a more concrete view of the encoder's behavior, in our experiments, we make use of the spatiotemporal decomposition layers provided by extensive studies on a previous retinal layer, the Outer Plexiform Layer (OPL). The decomposition layers produced by the OPL, are being encoded using our LIF image encoder and then, they are reconstructed to observe the encoder's efficiency.
Merkel cells (MCs) and associated primary sensory afferents of the whisker follicle-sinus complex, accurately code whisker self-movement, angle, and whisk phase during whisking. However, little is known about their ro...
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Merkel cells (MCs) and associated primary sensory afferents of the whisker follicle-sinus complex, accurately code whisker self-movement, angle, and whisk phase during whisking. However, little is known about their roles played in cortical encoding of whisker movement. To this end, the spiking activity of primary somatosensory barrel cortex (wS1) neurons was measured in response to varying the whisker deflection amplitude and velocity in transgenic mice with previously established reduced mechanoelectrical coupling at MC-associated afferents. Under reduced MC activity, wS1 neurons exhibited increased sensitivity to whisker deflection. This appeared to arise from a lack of variation in response magnitude to varying the whisker deflection amplitude and velocity. This latter effect was further indicated by weaker variation in the temporal profile of the evoked spiking activity when either whisker deflection amplitude or velocity was varied. Nevertheless, under reduced MC activity, wS1 neurons retained the ability to differentiate stimulus features based on the timing of their first post-stimulus spike. Collectively, results from this study suggest that MCs contribute to cortical encoding of both whisker amplitude and velocity, predominantly by tuning wS1 response magnitude, and by patterning the evoked spiking activity, rather than by tuning wS1 response latency.
A model of a biological sensory neuron stimulated by a noisy analog information source is considered. It is demonstrated that action-potential generation by the neuron model can be described in terms of lossy compress...
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ISBN:
(纸本)9780819465245
A model of a biological sensory neuron stimulated by a noisy analog information source is considered. It is demonstrated that action-potential generation by the neuron model can be described in terms of lossy compression theory. Lossy compression is generally characterized by (i) how much distortion is introduced, on average, due to a loss of information, and (ii) the 'rate.' or the amount of compression. Conventional compression theory is used to measure the performance of the model in terms of both distortion and rate, and the tradeoff between each. The model's applicability to a number of situations relevant to biomedical engineering, including cochlear implants, and bio-sensors is discussed.
Transmitting information in engineered neural communication systems is a promising solution for delay-sensitive applications in the internet of bio-nano things (IoBNTs). As widely used in wired and wireless communicat...
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ISBN:
(纸本)9781450398671
Transmitting information in engineered neural communication systems is a promising solution for delay-sensitive applications in the internet of bio-nano things (IoBNTs). As widely used in wired and wireless communication systems, multiplexing could also improve channel transmission efficiency for neural communication systems. In this paper, we model a neural communication system for IoBNTs and propose a neural signal multiplexing scheme for this system. It is a frequency-division multiplexing (FDM) based multiplexing strategy. The multiplexing, demultiplexing scheme, as well as decoding method are presented. The performance of the proposed strategy is evaluated and analyzed in terms of bit error rate and mutual information rate. The work can help researchers better understanding the underlying mechanism of neural multiplexing and pave the way for the implementation of IoBNT applications.
Purpose: Transcranial alternating current stimulation (tACS) is used as a brain stimulation mechanism to enhance learning, ameliorate some psychiatric disorders, and modify behavior. This study assessed the effects of...
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Purpose: Transcranial alternating current stimulation (tACS) is used as a brain stimulation mechanism to enhance learning, ameliorate some psychiatric disorders, and modify behavior. This study assessed the effects of near threshold tACS-like currents on Off-center and On-Off retinal ganglion cell responsiveness in the rabbit retina eyecup preparation as a model for central nervous system effects. Materials and Methods: We made extracellular recordings in the isolated rabbit eyecup preparation using single electrodes and microelectrode arrays to measure light-evoked spike responses in different classes of Off-center and On-Off retinal ganglion cells before, during, and after brief applications of alternating currents of 1-2 microamperes, at frequencies of 10, 20, 30, and 40 Hz. Results: tACS application sculpted the light-evoked response profiles without directly driving spiking activity of the 20 Off-center and On-Off ganglion cells we recorded from. During tACS application, Off responses were significantly enhanced for 6 cells and significantly suppressed for 14 cells, but after tACS application, Off responses were significantly enhanced for 7 cells and suppressed for 12 cells. The Off responses of the remaining two cells returned to baseline. On responses were less affected during and after tACS. Conclusion: tACS sculpts Off-center and On-Off retinal ganglion cell responsiveness. The dissimilarity of effects in different cells within the same class and the differential effects on the On and Off components of the light response within the same cell are consistent with the hypothesis that tACS acts at threshold on amacrine cells in the inner plexiform layer.
Analysis of linked spike activity in simultaneously recorded neurons in the rabbit sensorimotor cortex identified 22 closed neural circuits consisting of three or four neurons. In experiments using a model of a defens...
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The problem of electronic sensor interaction with the nervous system of a living organism in sensory prosthetics devices is described. The processing, storing and transmission of information by a spiking neuron and a ...
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ISBN:
(纸本)9781728103396
The problem of electronic sensor interaction with the nervous system of a living organism in sensory prosthetics devices is described. The processing, storing and transmission of information by a spiking neuron and a spiking neural network are analyzed. The basic principles of functioning of a neural cell, which uses an electric pulse for coding and transmission of information, are investigated. The possibility of developing an encoder for transmitting information from the sensor to the biological neuron of spiking neural networks is considered. The existing methods and means of sensory prosthetics and problems of hardware development for invasive and non-invasive systems are described.
Key to understanding somatosensation is the form of how the mechanical stimuli are represented in the evoked neuronal activity of the brain. Here, we focus on studies that address the question of which components of t...
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Key to understanding somatosensation is the form of how the mechanical stimuli are represented in the evoked neuronal activity of the brain. Here, we focus on studies that address the question of which components of the evoked neuronal activity in the somatosensory system represent the stimulus features. We review experiments that probe whether these neuronal representations are essential to somatosensation. We also discuss recent results that suggest how the somatosensory stimuli are represented in the brain during short-term memory. Finally, we review data that show the neuronal correlates of a decision during somatosensory perception. (C) 2002 Elsevier Science B.V. All rights reserved.
作者：
Giese, MAMIT
Ctr Biol & Computat Learning Cambridge MA 02139 USA
Focuses on two psychophysical experiments that demonstrate the multi-functional interactions in early visual motion processing. Details on the modularization of visual function; Challenges to various evidence from psy...
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Focuses on two psychophysical experiments that demonstrate the multi-functional interactions in early visual motion processing. Details on the modularization of visual function; Challenges to various evidence from psychophysical experiments; Implications ans unanswered questions.
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