How can i correct the error generated from running this code

a = 20E-6; % Cell radius (m) d = 2*a; % Cell diameter (m) L = 40.0E-6; % Cell length (m) temp = 6.3; % Temperature (deg. C) gmax_Na = (120E-3)*100^2; % Maximum sodium conductance per unit area (S/m^2) gmax_K = (36E-3)*100^2; % Maximum potassium conductance per unit area (S/m^2) co_Na = 491E-3; % Extracellular Na concentration (M/L) ci_Na = 50E-3; % Intracellular Na concentration (M/L) co_K = 20.11E-3; % Extracellular K concentration (M/L) ci_K = 400E-3; % Intracellular K concentration (M/L) C_m = (1.0E-6)*100^2; % Membrane capacitance per unit area (F/m^2) b = 0.02; % Relative sodium to potassium conductance delta_t = 1.0E-6; % Time step (s) max_time = 20.0E-3; % Maximum time (s) pulse_width = 10E-6; % Stimulus pulse width (s) pulse_amp = 59E-9; % Stimulus pulse amplitude (A)

% Compute cell parameter values Area = 2*(pi*a^2) + 2*pi*a*L; %area in m^2 C = Area*C_m; maxcond_Na = Area*gmax_Na; maxcond_K = Area*gmax_K; Na_Battery = V_Na(co_Na, ci_Na, temp); K_Battery = V_K(co_K, ci_K, temp); V_rest = V_r(co_Na, ci_Na, co_K, ci_K, temp, b); m_o = m_bound(V_rest); n_o = n_bound(V_rest); h_o = h_bound(V_rest);

% Set up the time vector t = zeros(floor(max_time/delta_t),1);

for i = 1:floor(max_time/delta_t) t(i) = (i-1)*delta_t; end

% Specify the initial conditions vector y0 = [V_rest, m_o, h_o, n_o]; options = odeset();

% Invoke the solver [T,Y] = ode45(@odefun, t, y0, options, C, maxcond_Na, maxcond_K, Na_Battery, K_Battery,pulse_width, pulse_amp);

% Plot the solution figure(1) plot(T,(Y(:,1)*10^3)) grid xlabel('Time(s)') ylabel('Transmembrane Potential(mV)') title('Action Potential')

figure(2) plot(T,Y(:,2)) hold on plot(T,Y(:,3),'r') hold on plot(T,Y(:,4),'g') grid xlabel('Time(s)') ylabel('Gating Variable') title('Gating Varible dynamics')

function ah = alpha_h(Vm) Vm = Vm/1.0E-3; ah = 0.07*exp(-0.05*(Vm+60));

function am = alpha_m(Vm) Vm = Vm/1.0E-3; if Vm ~= -35 am = -0.1*(Vm+35)/(exp(-0.1*(Vm+35))-1); end if Vm == -35 up = Vm + 1.0E-4; down = Vm - 1.0E-4; am =(-0.1*(up+35)/(exp(-0.1*(up+35))-1)+(-0.1)*(down+35)/(exp(-0.1*(down+35))-1))/2; end function an = alpha_n(Vm) Vm = Vm/1.0E-3; if Vm ~= -50 an = -0.01*(Vm+50)/(exp(-0.1*(Vm+50))-1); end if Vm == -50 up = Vm + 1.0E-4; down = Vm - 1.0E-4; an = (-0.01*(up+50)/(exp(-0.1*(up+50))-1) + -0.01*(down+50)/(exp(-0.1*(down+50))-1))/2; end function bh = beta_h(Vm) Vm = Vm/1.0E-3; bh = 1/(1+exp(-0.1*(Vm+30))); function bm = beta_m(Vm) Vm = Vm/1.0E-3; bm = 4.0*exp(-(Vm+60)/18); function bn = beta_n(Vm) Vm = Vm/1.0E-3; bn = 0.125*exp(-0.0125*(Vm+60)); function I = Current(t,pw,amp) if t >= 0.0 & t <= pw I = amp; else I = 0.0; end function hb = h_bound(Vm) hb = alpha_h(Vm)/(alpha_h(Vm)+beta_h(Vm)); function mb = m_bound(Vm) mb = alpha_m(Vm)/(alpha_m(Vm)+beta_m(Vm)); function nb = n_bound(Vm) nb = alpha_n(Vm)/(alpha_n(Vm)+beta_n(Vm));

function dy = odefun(t, y, Cm, GNamax, GKmax, VNa, VK, pw, amp); mf = m_bound(y(1)); hf = h_bound(y(1)); nf = n_bound(y(1)); taum = tau_m(y(1)); tauh = tau_h(y(1)); taun = tau_n(y(1)); dy = [-(GKmax/Cm)*(y(4)^4)*(y(1)-VK)-(GNamax/Cm)*(y(2)^3)*y(3)*(y(1)VNa)+Current(t,pw,amp)/Cm;

(mf-y(2))/taum; (hf-y(3))/tauh; (nf-y(4))/taun]; function th = tau_h(Vm) th = 1/((alpha_h(Vm)+beta_h(Vm)))*(1/1000); function tm = tau_m(Vm) tm = (1/(alpha_m(Vm)+beta_m(Vm)))*(1/1000); function tn = tau_n(Vm) tn = (1/(alpha_n(Vm)+beta_n(Vm)))*(1/1000);

function VK = V_K(co_K, ci_K, temp) R = 8.314; % Reiberg gas constant (joules/(mole*kelvin F = 9.648E4; % Faraday's constant (coulombs/mole). Z = 1; % Sodium and potassium ionic valence. TKelvin = 273.15 + temp; VK = ((R*TKelvin)/(Z*F))*log((co_K)/(ci_K)); function VNa = V_Na(co_Na, ci_Na, temp) R = 8.314; % Reiberg gas constant (joules/(mole*kelvin)). F = 9.648E4; % Faraday's constant (coulombs/mole). Z = 1; % Sodium and potassium ionic valence. TKelvin = 273.15 + temp; VNa = ((R*TKelvin)/(Z*F))*log((co_Na)/(ci_Na)); function Vr = V_r(coNa,ciNa,coK,ciK,T,b) R = 8.314; % Reiberg gas constant (joules/(mole*kelvin)). F = 9.648E4; % Faraday's constant (coulombs/mole). Z = 1; % Sodium and potassium ionic valence. TKelvin = 273.15 + T; Vr = ((R*TKelvin)/(Z*F))*log((coK + b*coNa)/(ciK + b*ciNa));

[Adam Danz]

This is too difficult to read. Please format your code by using the {} button and please explain the error you're getting (copy the error message) and what line produces the error.

Answer 1

[Kwabena Danso]

I have attached the the .m file which has the code.

After running it, i get this error:

Error: File: XXX.m Line: 45 Column: 3 Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

How can i rectify this.Thanks

[Peter Meglis]

Kwabena,

You can continue parameters onto the next line using "..."

[T,Y] = ode45(@odefun, t, y0, options, C, maxcond_Na, maxcond_K, Na_Battery, K_Battery,pulse_width, ...
pulse_amp);

On line 120, you're missing (I assume) an *

...(y(1)*VNa)...

I can't correct the rest of the syntax errors, make sure your functions have corresponding 'end' statements. Take a look at this Matlab Answer about nesting functions and using 'end':

https://www.mathworks.com/matlabcentral/answers/81085-function-without-matching-end

Hope this helps