function isih(spikes, bins)
isis = [];
for i = 1:length(spikes)
	times= spikes{i};
	isis = [isis; diff(times(:))];
end
[h, b] = hist(isis, bins);
h = h / sum(h) / (bins(2)-bins(1));
bar(1000.0*b, h);
xlim([0 1000.0*b(end)])
end