Help me
- To: mathgroup at yoda.physics.unc.edu
- Subject: Help me
- From: neurox.cu!bosch at ceniai.cu (Jorge Bosch)
- Date: Thu, 11 Feb 93 11:30:55 -0500
Hello, Mathgroup: I am new at Mathematica. I'm introducing this framework in my scientific group but I'm having trouble with it. I have installed 2.1 version of Mathematica under Windows, on an Acer 1100sx computer (16 MHz, 4 MBytes Extended Memory, 80387 Numerical Coprocessor), MSDOS Operating System. I am trying to solve a differential equation system (the Hoodgking and Huxley model for a neuron) but different solutions appear at different times and sometimes the computer crashes. Additionally, I can't reproduce the solution that I got with the same system programmed in Turbo Pascal. I enclose a copy of the non autonomous and non linear differential equation system (four equations) as I am using. I will really appreciate if someone could help me to find out what is wrong in my system. Thanks in advance Jorge Bosch a1[v_]:=0.1 (25-v)/(Exp[(25-v)/10]-1) b1[v_]:=4 Exp[-v/18] a2[v_]:=0.07 Exp[-v/20] b2[v_]:=1/(Exp[(30-v)/10]+1) a3[v_]:=0.01 (10-v)/(Exp[(10-v)/10]-1) b3[v_]:=0.125 Exp[-v/80] c1oo[v_]:=a1[v]/(a1[v]+b1[v]) c2oo[v_]:=a2[v]/(a2[v]+b2[v]) c3oo[v_]:=a3[v]/(a3[v]+b3[v]) i[t_]:=If[t>=0.5 && t<=7.55,130,0] rm=35.4; cm=1; gnax=120; gkx=36; glx=0.3; vna=115; vk=-12; vl=11; Plot[i[t],{t,0,10},PlotPoints->100] NDSolve[{v'[t]==-(gnax m[t]^3 h[t] (v[t]-vna) + gkx n[t]^4 (v[t]-vk) + glx (v[t]-vl) + v[t]/rm - i[t]), m'[t]==a1[v[t]](1-m[t])-b1[v[t]] m[t], n'[t]==a2[v[t]](1-n[t])-b2[v[t]] n[t], h'[t]==a3[v[t]](1-h[t])-b3[v[t]] h[t], v[0]==0, m[0]==c1oo[0], n[0]==c2oo[0], h[0]==c3oo[0]}, {v[t],n[t],m[t],h[t]},{t,0,10}] Plot[Evaluate[v[t]/.%],{t,0,10},PlotPoints->100];