The 3-dimensional representation of EEG distance by use of Shannon-Gelfand-Yaglom information measure during mental arithmetic.

EEG relationships in delta, theta, alpha and beta frequency bands as well as the whole frequency range among 12 electrode locations during resting and mental arithmetic were examined by use of Shannon-Gelfand-Yaglom information measure (SGY) in 10 normal subjects. The EEG relationships were represented in a 3-dimensional (3-D) feature space with multidimensional scaling (MDS). MDS resulted in an anterior-posterior, a left-right and an upper-lower axis. In all 5 frequency bands, the 12 electrodes on the anterior-posterior and left-right axes resembled their actual positions on the scalp during resting and mental arithmetic. During mental arithmetic, prominent changes in the 3-D representation of electrode sites were visualized for activity. The isolation of left and right mid-temporal locations, together with greater EEG distances between left and right mid-temporal locations, were notable during mental arithmetic, suggesting the simultaneous activation possibly in dominant and non-dominant hemispheres and contralateral influences from left to right mid-temporal locations.