function EEG = MakeEEG(Im, PosData)
% This fucntion determines the field generated by the SPyr cells
nCell = size(Im,2);
Depth = PosData(1:nCell,3);
Contribution = Im;
for iCell = 1:nCell
Contribution(:,iCell) = Contribution(:,iCell)/Depth(iCell);
end
EEG = -sum(Contribution,2);