40
Soma Voltage Errors (Quasi-active vs. ВТ)
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Time (ms)
Comparison of Computed Soma Voltages
Soma Voltage Errors with Tonic Synapses (Quasi-active vs. BT)
0.8
ω -0.4
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Time (ms)
Figure 2.7: A) Hankel singular values for the forked neuron given a 2 μm compartment size. Since
there are 301 compartments and the HH ion channels have 3 gating variables, the quasi-active system
has 1204 variables; hence the BT system has the same number of HSVs. B) Absolute and relative
errors between the computed soma potentials of the quasi-active and BT systems. C) Computed
soma potentials from the nonlinear, quasi-active, and BT simulations. At the 1 ms mark a 1 nS
alpha-function synaptic input with time constant τ = 1 ms was applied to the midpoint of the
top distal branch. Notice that the quasi-active and BT curves are indistinguishable. D) Resting
potential of each node for the forked neuron with 10% tonic synapses of gbs = 0.2 nS each. In the
absence of tonic synapses, each node is at rest at ≈ —64.9186 mV. The faint dotted line indicates
the end of a branch. E-F) Same as (B-C), but for the case of tonic synapses. Notice that tonic
synapses induce more oscillations for the exact same stimulus.
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Time (ms)
Comparison of Computed Soma Voltages with Tonic Synapses
0.8r r-
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Time (ms)
tonic components gbs = 0.2 nS, which changes the rest potential of the neuron from
a uniform value of ≈ —64.9186 mV to one that is now spatially-varying and elevated
(Figure 2.7D). Using the exact same stimulus as used for Figure 2.7B-C, we find that