Intracerebral dipole source localization for FFT power maps.

The method treats Fast Fourier Transforms (FFTs) of multichannel EEGs so that they can be used for intracerebral source localizations. For each frequency point, the FFT results are entered into a sine-cosine diagram. Into the diagram's entry constellation (FFT constellation), a straight line (single dipole model) is fitted which produces the least square deviation sum between the entry positions and their orthogonal projections onto the straight line. The map described by the voltages between the projected positions on the straight line is the single source 'FFT approximation' of the FFT constellation. The FFT approximation map is used for dipole source localization. The squared FFT approximation map and the squared map of the forward solution of the computed dipole (power maps) closely resemble the original power map.