maxisi = 300.0;
poissonisis = isis(poissonspikes);
rate = 1.0/mean(poissonisis);
plotisihist(poissonisis, 0.001);
tt = linspace(0.0, 0.001*maxisi, 200);
pexp = rate*exp(-tt*rate);
hold on;
plot(1000.0*tt, pexp, 'r')
hold off;
xlim([0, maxisi])
title('Poisson');
savefigpdf(gcf, 'poissonisihist.pdf', 10, 7);