function y = spike_filter_binned(ts,fromto,bins,krn,varargin)
% this function uses qcount_binned to normalize trial time length and
% calculate "squeezed" psth.
binsz=5e-4	; 
normalize_krn=  1       ; 

utils.overridedefaults(who, varargin)

if normalize_krn
    krn = krn/sum(abs(krn))/binsz; % normalize
end
offset = ceil(length(krn)/2);
buffer=offset*binsz;
fromto = [fromto(:,1) - buffer,fromto];
bins = [offset,bins];
y = stats.qcount_binned(ts,fromto,bins);
y = [y,zeros(size(y,1),offset)];
y = filter(krn, 1, y, [], 2);
y = y(:, 2*offset:end-1); % trim extra columns
end