%subplot(5,4,1) 
a=0.02; b=0.2;  c=-65;  d=6;
V=-70;  u=b*V;
VV=[];  uu=[];
tau = 0.25; tspan = 0:tau:100;
T1=tspan(end)/10;
for t=tspan
    if (t>T1) 
        I=14;
    else
        I=0;
    end;
    V = V + tau*(0.04*V^2+5*V+140-u+I);
    u = u + tau*a*(b*V-u);
    if V > 30
        VV(end+1)=30;
        V = c;
        u = u + d;
    else
        VV(end+1)=V;
    end;
    uu(end+1)=u;
end;
plot(tspan,VV,[0 T1 T1 max(tspan)],-90+[0 0 10 10]);
axis([0 max(tspan) -90 30])
axis off;

% title('(A) tonic spiking');

set(gcf,'Units','normalized','Position',[0.3 0.1 0.6 0.8]);


% try
% tspan=0:5 
% for t=tspan
%   vv(end+1)=t
% end

% try
% plot([0 2 2 3], [5 6 8 9])