Set up the default plotting parameters
set(0,'DefaultLineLineWidth',2,...
'DefaultLineMarkerSize',8, ...
'DefaultAxesLineWidth',2, ...
'DefaultAxesFontSize',14,...
'DefaultAxesFontWeight','Bold');
figure(1)
clf;
Simulation Parameters
dt = 0.0001; % time-step
t = 0:dt:0.5; % vector of time-points
ton = 0.15; % time to begin applied current (onset)
toff = 0.35; % time to end applied current (offset)
non = round(ton/dt); % time-point index of current onset
noff = round(toff/dt); % time-point index of current offset
Parameters for the LIF neuron
tau = 0.010; % membrane time constant
E_L = -0.070; % leak potential (also resting potential)
Vth = -0.050; % threshold potential (to produce spike)
Vreset = -0.080; % reset potential (post-spike)
Cm = 100e-12; % total membrane capacitance
G_L = Cm/tau; % total membrane conductance (leak conductance)
LIF Neuron Simulation
Iapp = 210e-12; % value of applied current steps
I = zeros(size(t)); % vector for current at each time-point
I(non:noff) = Iapp; % add the applied current
V = E_L*ones(size(t)); % initialize the membrane potential vector
spikes = zeros(size(t)); % initialize a vector to record spikes
for i = 2:length(t); % loop through all time points
% next line: Forward Euler method to update membrane potential
V(i) = V(i-1) + dt*(I(i) +G_L*(E_L-V(i-1)))/Cm;
if V(i) > Vth; % if potential is above threshold
spikes(i) = 1; % record the spike at that time-point
V(i) = Vreset; % reset the potential
end;
end; % end the loop & go to next time-point
Plotting Current Against Time
figure(1)
plot(t,I*1e9,'k'); % Plot current (in nA) against time
ylabel('I_{app} (nA)')
% The following line adds a title, which uses the command "strcat" to
% combine the value of current in that trial with "nA" to make a
% complete title.
% The command "num2str" converts the number representing the applied
% current into a string, which is something that can be printed.
title(strcat(num2str(1e9*Iapp),'nA'))
set(gca,'XTick',[0 0.25 0.5])
axis([0 0.5 0 0.3]) % Sets x-axis then y-axis ranges
Plotting Membrane Potential Against Time
figure(2)
plot(t,1000*V,'k'); % Plot membrane potential vs time
ylabel('V_m (mV)') ㄴ % Label y-axis
set(gca,'XTick',[0 0.25 0.5])
axis([0 0.5 1000*(Vreset-0.005) 1000*(Vth+0.005)]) % Set the axes
Plotting Spikes Against Time
figure(3)
plot(t,spikes,'k') % Plots a line from 0 to 1 at each spike
xlabel('Time (sec)') % Label the x-axis
ylabel('Spikes') % Label the y-axis
set(gca,'XTick',[0 0.25 0.5])
set(gca,'YTick',[0 1])
axis([0 0.5 0 1]) % Set the ranges of x- and y-axes
