Regression model similar to neuron action potential? On the wiki page for depolarization they show a plot of the action potential in a neuron exhibiting depolarization. See below.

I am actually modelling gene expression over time, and some of the genes in my data have a time-dependence similar to the plot above. The key features of this curve that interest me:

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*Initial baseline.

*Asymmetric peak.

*Drop below baseline after peak.

*Monotonic increase back to baseline.

Is there a parametric model for this kind of time-dependence curve?

I am not aware of a parametric model for an action potential but using Fourier analysis you can get a decomposition in sines or cosines that may recreate your curve very accurately. To do that you need to digitize the curve you are showing and get the Fourier spectrum.The book I used  decades ago is "The FFT, Fundamentals and Concepts" by Robert W. Ramirez. It is good but I am sure there are more updated sources.
