Neuro 317 Methods in Computational Neurobiology
Univ. of Illinois, Urbana-Champaign
Prof. Mark Nelson

Homework 2 - Problem 2

2. Now examine the response of your IAF model to sinusoidal stimulation. Use the same neuron parameters as in the previous problem (HW #2.1a), but use a sinusoidal current injection with a peak amplitude of 1 nA.

(a) Plot "membrane potential vs. time" for the following seven stimulus frequencies: 1, 2, 5, 10, 20, 50, 100 Hz. Use a total stimulus duration of 1 second. Your graph should look similar to the attached plot. (HINT: You can overlay multiple responses on the same plot by adding a vertical offset to each successive trace.)

(b) Now generate a plot of "spike count vs. stimulus frequency," where "spike count" is the total number of spikes generated during the 1 second stimulus interval. Plot your results using a logarithmic scale for the X-axis (MATLAB semilogx function). Your graph should look similar to the attached plot. Why does the total spike count decrease with increasing stimulus frequency?


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