spike_length = 1/1000; % s
rate = 8000; % samplas per s
filename = 'spikes.wav';
points = rate * spike_length;
load cell_times.txt;
spike = sin(linspace(0,2*pi,points))';
end_time = ceil(max(max(cell_times)));
end_sample = (end_time + spike_length) * rate; 
left = zeros(end_sample, 1);
right = zeros(end_sample, 1);
for i = 1 : size(cell_times, 1),
   for j = 1 : size(cell_times, 2),
      position = cell_times(i, j);
      if isfinite(position),
         position = round(position * rate);
         right(position : position + points - 1) = right(position : position + points - 1) + spike;
         left(position : position + points - 1) = left(position : position + points - 1) - spike;
      end;
   end;
end;
wavwrite([left, right], rate, filename);