Magnetoencephalographic and electroencephalographic studies of spontaneous activity and evoked responses in the sensorimotor system

.......................................................................................................................... 6 Introduction ................................................................................................................... 7 Review of literature ..................................................................................................... 8 Oscillatory brain activity.................................................................................................. 8 Alpha rhythm ...................................................................................................................... 8 Mu and beta rhythms........................................................................................................... 9 Self-organized criticality (SOC)..................................................................................... 10 Synchrony in the brain ................................................................................................... 11 Somatosensory system and primary motor cortex....................................................... 11 Receptors and spinal cord ................................................................................................. 11 Brain stem and thalamus ................................................................................................... 12 Primary somatosensory cortex (SI)................................................................................... 12 Secondary somatosensory cortex (SII) ............................................................................. 13 Posterior parietal cortex (PPC) ......................................................................................... 14 Other areas related to somatosensory processing ............................................................. 14 Primary motor cortex (MI)................................................................................................ 14 Somatosensory evoked responses .................................................................................. 15 Somatosensory evoked potentials (SEP)........................................................................... 15 Somatosensory evoked fields (SEF) ................................................................................. 16 Experimental techniques ................................................................................................ 17 Magnetoand Electroencephalography (MEG, EEG) ...................................................... 17 Transcranial magnetic stimulation (TMS) ........................................................................ 17 Aims of study ............................................................................................................... 19 Materials and methods............................................................................................. 20 Stimulation........................................................................................................................ 20 Recordings ........................................................................................................................ 20 Data analysis ..................................................................................................................... 21 Results and discussion ............................................................................................. 22 I. Suppression of mu rhythm by somatosensory stimulation.................................... 22 Results............................................................................................................................... 22 Discussion ......................................................................................................................... 23