Clusterization of magnetic field patterns associated with occipital alpha rhythm

Magnetic field patterns recorded with 37-channel KRENIKON^® magnetometer over occipital head during alpha rhythmic activity of the human subject were classified. The patterns were analyzed in a form of two-dimentional Fourier transforms. On the first stage the patterns of dipolar structure were preselected. These patterns can be split into two clusters. The clusters corre­spond to clearly discernable electric processes in a restricted area of occipital lobes. Equivalent current dipoles for these processes are separated by about 10 mm. Simultaneous contributions from other sources outside this area were disregarded by the selection proce­dure. The approach demonstrates ability of the multichannel magnetoencephalography to discriminate sources of spontaneous activity in the human brain.