To determine whether dipoles are an appropriate simplified representation of neural sources for stereo-EEG (sEEG).We compared the distributions of voltages generated by a dipole, biophysically realistic cortical neuron models, and extended regions of cortex to determine how well a dipole represented neural sources at different spatial scales and at electrode to neuron distances relevant for sEEG. We also quantified errors introduced by the dipole approximation of neural sources in sEEG source localization using standardized low-resolution electrotomography (sLORETA).For pyramidal neurons, the coefficient of correlation between voltages generated by a dipole and neuron model were 0.9 for distances 1 mm. For small regions of cortex (∼0.1 cmSingle dipoles are an appropriate source model to represent both single neurons and small regions of active cortex, while multiple dipoles are required to represent large regions of cortex.Dipoles are computationally tractable and valid source models for sEEG.
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