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. Author manuscript; available in PMC: 2016 Feb 10.
Published in final edited form as: Prog Mol Biol Transl Sci. 2014;123:305–350. doi: 10.1016/B978-0-12-397897-4.00004-8

Figure 13.4. Simulated spike trains with refractoriness and pseudorandom timing.

Figure 13.4

(A1) Trains of spike event times (top) computed for an instantaneous rate function λ(t) with exponential decay time constant of 150 ms (bottom, solid red line) and absolute refractory period (τAR) of 1 ms. To compute the trains, a refractory-corrected rate function Λ(t) (dashed red line) was first derived from Eq. (13.18) and then used in the integral of Eq. (13.15) to compute the spike intervals in sequence. The PSTH (black, 2-ms bins) computed from 200 such trains closely matches λ(t). (A2) Interspike interval histogram (ISIH) computed from the same 200 trains in (A1), showing the 1 ms absolute refractory period. The overall exponential decay of the ISIH is a hallmark sign of a random Poisson process. (B1) and (B2) Same as (A1) and (A2) except λ(t) was a half-wave rectified sinusoid with 250 ms period, and refractoriness was both absolute and relative: τAR = 0.5 ms and τRR = 0.5 ms. Intervals were computed via Eq. (13.19).