97 research outputs found
A mean-field model for conductance-based networks of adaptive exponential integrate-and-fire neurons
Voltage-sensitive dye imaging (VSDi) has revealed fundamental properties of
neocortical processing at mesoscopic scales. Since VSDi signals report the
average membrane potential, it seems natural to use a mean-field formalism to
model such signals. Here, we investigate a mean-field model of networks of
Adaptive Exponential (AdEx) integrate-and-fire neurons, with conductance-based
synaptic interactions. The AdEx model can capture the spiking response of
different cell types, such as regular-spiking (RS) excitatory neurons and
fast-spiking (FS) inhibitory neurons. We use a Master Equation formalism,
together with a semi-analytic approach to the transfer function of AdEx
neurons. We compare the predictions of this mean-field model to simulated
networks of RS-FS cells, first at the level of the spontaneous activity of the
network, which is well predicted by the mean-field model. Second, we
investigate the response of the network to time-varying external input, and
show that the mean-field model accurately predicts the response time course of
the population. One notable exception was that the "tail" of the response at
long times was not well predicted, because the mean-field does not include
adaptation mechanisms. We conclude that the Master Equation formalism can yield
mean-field models that predict well the behavior of nonlinear networks with
conductance-based interactions and various electrophysiolgical properties, and
should be a good candidate to model VSDi signals where both excitatory and
inhibitory neurons contribute.Comment: 21 pages, 7 figure
Development of space-stable thermal-control coatings Triannual report, Jan. 20 - Jun. 20, 1966
Thermal stability of double zirconium silicate pigment coatings, and of potassium silicate treated zinc oxide and silicone paint
Preparation of S-13 experimental coatings Final report, Oct. 29, 1963 - Aug. 31, 1965
Elastomeric methyl silicone polymer thermal control coating evaluation with Pegasus spacecraf
Development of space-stable thermal-control coatings Triannual report, Sep. 20, 1965 - Jan. 20, 1966
Space stable thermal control surface coatings - inorganic pigments and ultraviolet photolysis of methyl silicone polymer
Study of in-situ degradation of thermal control surfaces
Experimental technique used in study of damage mechanism to semiconductor pigments exposed to ultraviolet radiation can be adapted for investigations of surface chemistry and may be used analytically to determine contamination
Development of S-13G-type coatings as engineering materials Final report, 1 Sep. 1966 - 31 Aug. 1968
S-13G type thermal control coatings for space application
Development of space-stable thermal-control coatings Triannual report, 1 Nov. 1967 - 29 Feb. 1968
Reactive encapsulation methods for thermal stabilization of zinc orthotitanate resin paints for spacecrafts material
The behavior of several white pigments as determined by in situ reflectance measurements of irradiated specimens
Reflectance measurements of irradiated specimens of zinc oxide and zinc orthotitanate white pigment material
Investigation of environmental effects on coatings for thermal control
Accomplishments made during study of coatings are reported. Development of structure/property theory for selecting most appropriate pigments for space vehicle paints is discussed along with improvements made in zinc-oxide pigmented potassium silicate paint
Summary of investigations of light scattering in highly reflecting pigmented coatings
Light scattering in highly reflecting pigmented coatings - silver bromide and particle suspensions and paint film
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