Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Title: ¬The¬ book of GENESIS : exploring realistic neural models with GEneral NEural SImulation System + CD-ROM
    Author: Bower, James M.
    Contributer: Beeman, David
    Edition: 2nd ed.
    Publisher: New York; Telos, Santa Clara :Springer,
    Year of publication: 1998
    Pages: 458 S.
    Type of Medium: Book
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1106
    Keywords: Cerebellum ; Plateau ; Facial ; Crus IIa Guinea pig ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We obtained intracellular recordings of 84 Purkinje cells in vitro from guinea pig slices and of 35 cells in vivo from ketamine-anesthetized rats in order to assess detailed properties of synaptic responses in Purkinje cells following granule cell activation. In vitro, electrical stimulation of the granule cell layer underlying recorded Purkinje cells was used in sagittal slices to predominantly activate synapses on ascending granule cell axons. In vivo, stimulation of the upper lip was used to activate Purkinje cells overlying the upper lip patch in the granule cell layer of crus IIa. In the presence of a GABAA antagonist, Purkinje cells at resting membrane potential responded to both electrical stimulation in vitro and peripheral stimulation in vivo, with a depolarization of 1–10 mV amplitude that lasted for 100–300 ms in the absence of climbing fiber input. Similar prolonged depolarizations could also be induced by brief depolarizing current pulses delivered through the recording electrode, demonstrating that either synaptic or direct depolarization may activate inward currents leading to a sustained response. In support of this hypothesis we found that prolonged depolarizations were shortened significantly when stimulation in the granule cell layer or intracellular current pulses were delivered during hyperpolarizing current steps. Stimulation in the granule cell layer or intracellular current pulses delivered during periods of spontaneous somatic spiking resulted in prolonged depolarizations in dendritic recordings, which were accompanied by an increase in somatic spiking frequency. Following upper lip stimulation in vivo, this increase in somatic spiking was interrupted by an inhibition of 10–50 ms duration. In a majority of recordings, this inhibition did not completely abolish prolonged depolarizations, however, and a delayed increase in somatic spike frequency was still observed. These results suggest that prolonged increases in Purkinje cell spike frequency following peripheral stimulation are due to an underlying prolonged dendritic depolarization induced by granule cell input. Further, a single, short burst of input via ascending granule cell axons appears to be sufficient to induce these responses.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1106
    Keywords: Field potential ; Timing ; Lidocaine ; Somatosensory cerebral cortex ; Crus IIa ; Mossy fiber ; Cerebellum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The spatial coincidence of somatosensory cerebral cortex (SI) and trigeminal projections to the cerebellar hemisphere has been previously demonstrated. In this paper we describe the temporal relationship between tactilely-evoked responses in SI and in the granule cell layer of the cerebellar hemisphere, in anesthetized rats. We simultaneously recorded field potentials in areas of common receptive fields of SI and of the cerebellar folium crus IIa after peripheral tactile stimulation of the corresponding facial area. Response of the cerebellar granule cell layer to a brief tactile stimulation consisted of two components at different latencies. We found a strong correlation between the latency of the SI response and that of the second (long-latency) cerebellar component following facial stimulation. No such relationship was found between the latency of the SI response and that of the first (short-latency) cerebellar component, originating from a direct trigeminocerebellar pathway. In addition, lidocaine pressure injection in SI, cortical ablation, and decerebration all significantly affected the second cerebellar peak but not the first. Further, when tactile stimuli were presented 75 ms apart, the response in SI failed, as did the second cerebellar peak, while the shortlatency cerebellar response still occurred. We found a wide spatial distribution of the upper lip response beyond the upper lip area in crus IIa for the long-latency component of the cerebellar response. Our results demonstrate that SI is the primary contributor to the cerebellar long-latency response to peripheral tactile stimulation. These results are discussed in the context of Purkinje cell responses to tactile input.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computational neuroscience 1 (1994), S. 9-10 
    ISSN: 1573-6873
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-6873
    Keywords: olfaction ; olfactory bulb ; mitral/tufted cell ; stereo electrode ; multiday recording ; chronic implant ; awake behaving ; distributed representation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine , Physics
    Notes: Abstract Chronic single-unit recordings were obtained from the mitral celllayer of the olfactory bulbs of awake freely moving rats placed in anodorant stream. Over periods up to five days, 618 recordings from 186single neurons were obtained. Responses of individual neurons werefound to be quite variable over time, although this variability wasbelow chance and was not incremental. The responses of nearbyneurons were more similar than expected by chance but less similarthan individual neurons recorded at different times. However,responses of spatially well-separated neurons were more differentthan chance over short time periods. During rapid sniffing,single-unit responses became more variable, and the spatialorganization of responses became less apparent. These results suggestthat neuronal responses in the olfactory bulb are generally quitevariable over time, with this variability increasing during periodsof rapid sniffing. These results are interpreted in the context of adistributed, centrally modulated model of olfactoryprocessing.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computational neuroscience 5 (1998), S. 285-314 
    ISSN: 1573-6873
    Keywords: Bayesian ; compartmental model ; model comparison
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine , Physics
    Notes: Abstract Computational modeling is being used increasingly in neuroscience. In deriving such models, inference issues such as model selection, model complexity, and model comparison must be addressed constantly. In this article we present briefly the Bayesian approach to inference. Under a simple set of commonsense axioms, there exists essentially a unique way of reasoning under uncertainty by assigning a degree of confidence to any hypothesis or model, given the available data and prior information. Such degrees of confidence must obey all the rules governing probabilities and can be updated accordingly as more data becomes available. While the Bayesian methodology can be applied to any type of model, as an example we outline its use for an important, and increasingly standard, class of models in computational neuroscience—compartmental models of single neurons. Inference issues are particularly relevant for these models: their parameter spaces are typically very large, neurophysiological and neuroanatomical data are still sparse, and probabilistic aspects are often ignored. As a tutorial, we demonstrate the Bayesian approach on a class of one-compartment models with varying numbers of conductances. We then apply Bayesian methods on a compartmental model of a real neuron to determine the optimal amount of noise to add to the model to give it a level of spike time variability comparable to that found in the real cell.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computational neuroscience 5 (1998), S. 315-329 
    ISSN: 1573-6873
    Keywords: synchrony ; cortical oscillators ; phase model ; synaptic effects ; dendritic delay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine , Physics
    Notes: Abstract We explore the influence of synaptic location and form on the behavior of networks of coupled cortical oscillators. First, we develop a model of two coupled somatic oscillators that includes passive dendritic cables. Using a phase model approach, we show that the synchronous solution can change from a stable solution to an unstable one as the cable lengthens and the synaptic position moves further from the soma. We confirm this prediction using a system of coupled compartmental models. We also demonstrate that when the synchronous solution becomes unstable, a bifurcation occurs and a pair of asynchronous stable solutions appear, causing a phase lag between the cells in the system. Then using a variety of coupling functions and different synaptic positions, we show that distal connections and broad synaptic time courses encourage phase lags that can be reduced, eliminated, or enhanced by the presence of active currents in the dendrite. This mechanism may appear in neural systems where proximal connections could be used to encourage synchrony, and distal connections and broad synaptic time courses could be used to produce phase lags that can be modulated by active currents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computational neuroscience 7 (1999), S. 149-171 
    ISSN: 1573-6873
    Keywords: parameter search ; compartmental model ; genetic algorithm ; simulated annealing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine , Physics
    Notes: Abstract One of the most difficult and time-consuming aspects of building compartmental models of single neurons is assigning values to free parameters to make models match experimental data. Automated parameter-search methods potentially represent a more rapid and less labor-intensive alternative to choosing parameters manually. Here we compare the performance of four different parameter-search methods on several single-neuron models. The methods compared are conjugate-gradient descent, genetic algorithms, simulated annealing, and stochastic search. Each method has been tested on five different neuronal models ranging from simple models with between 3 and 15 parameters to a realistic pyramidal cell model with 23 parameters. The results demonstrate that genetic algorithms and simulated annealing are generally the most effective methods. Simulated annealing was overwhelmingly the most effective method for simple models with small numbers of parameters, but the genetic algorithm method was equally effective for more complex models with larger numbers of parameters. The discussion considers possible explanations for these results and makes several specific recommendations for the use of parameter searches on neuronal models.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-7462
    Keywords: neurobiology ; olfaction ; associative memory ; simulations ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract During learning of overlapping input patterns in an associative memory, recall of previously stored patterns can interfere with the learning of new patterns. Most associative memory models avoid this difficulty by ignoring the effect of previously modified connections during learning, by clamping network activity to the patterns to be learned. Through the interaction of experimental and modeling techniques, we now have evidence to suggest that a somewhat analogous approach may have been taken by biology within the olfactory cerebral cortex. Specifically we have recently discovered that the naturally occurring neuromodulator acetylcholine produces a variety of effects on cortical cells and circuits which, when taken together, can prevent memory interference in a biologically realistic memory model. Further, it has been demonstrated that these biological mechanisms can actually improve the memory storage performance of previously published abstract “neural network” associative memory models.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...