A non-invasive technique, magnetoencephalography (MEG) can measure magnetic fields originating mainly from the intracellular current flow through the apical dendrites of cortical pyramidal neurons, which is caused by excitatory synaptic inputs. Our recent MEG studies on sensory and motor functions of the human brain are reviewed. MEG provides an effective non-invasive approach to the studies of human brain functions, especially when combined with appropriate animal experiments.