function vValue = VoxelValueAtTimepoint (coordinate, timepoint)
% single Voxel for single coordinate

if(size(coordinate,2)>1)
    error('VoxelValueAtTimepoint:CoordinateError','only single Coordinate permitted.');
end

imageNumber = timePointToImageNumber(timepoint, 's');
V           = evalin('base','SPM.xY.VY'); % Memory Mapped Images
center      = round(inv(V(imageNumber).mat)*[coordinate; 1]);

x           = center(1,1);
y           = center(2,1);
z           = center(3,1);

vValue      = spm_sample_vol(V(imageNumber), x, y, z, 0);

end