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[3] [5] Twin studies show its pattern is largely genetically determined since there is a heritability of 0.40 for the mean cortisol increase after awakening and 0.48 for the area under the cortisol rise curve. [6] Normally, the highest cortisol secretion happens in the second half of the night with peak cortisol production occurring in the ...
Spike times and subthreshold voltage of cortical neuron models can be predicted by generalized integrate-and-fire models such as the adaptive integrate-and-fire model, the adaptive exponential integrate-and-fire model, or the spike response model. In the example here, adaptation is implemented by a dynamic threshold which increases after each ...
In 1973, M. M. Taylor [1] suggested that if synapses were strengthened for which a presynaptic spike occurred just before a postsynaptic spike more often than the reverse (Hebbian learning), while with the opposite timing or in the absence of a closely timed presynaptic spike, synapses were weakened (anti-Hebbian learning), the result would be an informationally efficient recoding of input ...
If each spike is independent of all the other spikes in the train, the temporal character of the neural code is determined by the behavior of time-dependent firing rate r(t). If r(t) varies slowly with time, the code is typically called a rate code, and if it varies rapidly, the code is called temporal.
11-Deoxycortisol in mammals has limited glucocorticoid activity, but it is the direct precursor of the major mammalian glucocorticoid, cortisol. [15] As a result, the level of 11-deoxycortisol is measured to diagnose impaired cortisol synthesis, to find out the enzyme deficiency that causes impairment along the pathway to cortisol, and to differentiate adrenal disorders.
The spike response model (SRM) [1] is a spiking neuron model in which spikes are generated by either a deterministic [2] or a stochastic [1] threshold process. In the SRM, the membrane voltage V is described as a linear sum of the postsynaptic potentials (PSPs) caused by spike arrivals to which the effects of refractoriness and adaptation are added.
The biologically inspired Hodgkin–Huxley model of a spiking neuron was proposed in 1952. This model describes how action potentials are initiated and propagated. . Communication between neurons, which requires the exchange of chemical neurotransmitters in the synaptic gap, is described in various models, such as the integrate-and-fire model, FitzHugh–Nagumo model (1961–1962), and ...
The model is based on data from the squid giant axon and consists of nonlinear differential equations that approximate the electrical characteristics of a neuron, including the generation and propagation of action potentials. The model is so successful at describing these characteristics that variations of its "conductance-based" formulation ...