function rate = firingrate(spikes, tmin, tmax)
% mean firing rate between tmin and tmax.
rates = zeros(length(spikes), 1);
for i = 1:length(spikes)
	times= spikes{i};
	rates(i) = length(times((times>=tmin)&(times<=tmax)))/(tmax-tmin);
end
rate = mean(rates);
end