Slow repetitive transcranial magnetic stimulation increases somatosensory high-frequency oscillations in humans

Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a possible treatment for psychiatric and neurological disorders characterized by focal brain excitability, such as major depression and action myoclonus. However, the mechanism of modulating excitability by rTMS is unclear. We examined the changes in high frequency oscillations (HFOs) of somatosensory evoked potentials (SEPs) before and after slow rTMS over the right primary somatosensory cortex (0.5 Hz, 50 pulses, 80% motor threshold intensity). The HFOs, which represent a localized activity of intracortical inhibitory interneurons, were significantly increased after slow rTMS, while the SEPs were not changed. Our results suggest that slow rTMS affects cortical excitability by modulating the activity of the intracortical inhibitory interneurons beyond the time of the stimulation and that rTMS may have therapeutic effects on such disorders.

[1]  G. Curio,et al.  Propofol narcosis dissociates human intrathalamic and cortical high‐frequency (> 400 Hz) SEP components , 2000, Neuroreport.

[2]  L. Cohen,et al.  Reduction of human visual cortex excitability using 1-Hz transcranial magnetic stimulation , 2000, Neurology.

[3]  Á. Pascual-Leone,et al.  Subthreshold low frequency repetitive transcranial magnetic stimulation selectively decreases facilitation in the motor cortex , 2002, Clinical Neurophysiology.

[4]  T Imada,et al.  Somatic evoked high-frequency magnetic oscillations reflect activity of inhibitory interneurons in the human somatosensory cortex. , 1996, Electroencephalography and clinical neurophysiology.

[5]  F. Dudek,et al.  Intracellular correlates of fast (>200 Hz) electrical oscillations in rat somatosensory cortex. , 2000, Journal of neurophysiology.

[6]  J C Rothwell,et al.  Short-lasting impairment of tactile perception by 0.9Hz-rTMS of the sensorimotor cortex , 2003, Neurology.

[7]  Mark A Frye,et al.  Frequency dependence of antidepressant response to left prefrontal repetitive transcranial magnetic stimulation (rTMS) as a function of baseline cerebral glucose metabolism , 1999, Biological Psychiatry.

[8]  Alvaro Pascual-Leone,et al.  Handbook of transcranial magnetic stimulation , 2002 .

[9]  Y. Haruta,et al.  Specific somatosensory processing in somatosensory area 3b for human thumb: a neuromagnetic study , 2001, Clinical Neurophysiology.

[10]  S. Small,et al.  Somatotopy in human primary motor and somatosensory hand representations revisited. , 2001, Cerebral cortex.

[11]  G Curio,et al.  High frequency (600 Hz) bursts of spike-like activities generated in the human cerebral somatosensory system. , 1999, Electroencephalography and clinical neurophysiology. Supplement.

[12]  Y. Ugawa,et al.  Decreased sensory cortical excitability after 1 Hz rTMS over the ipsilateral primary motor cortex , 2001, Clinical Neurophysiology.

[13]  M. Hallett,et al.  Depression of motor cortex excitability by low‐frequency transcranial magnetic stimulation , 1997, Neurology.

[14]  Yasuhiko Saito,et al.  Reciprocal modulation of somatosensory evoked N20m primary response and high-frequency oscillations by interference stimulation , 1999, Clinical Neurophysiology.

[15]  Isao Hashimoto,et al.  The later part of high-frequency oscillations in human somatosensory evoked potentials is enhanced in aged subjects , 1999, Neuroscience Letters.

[16]  I Hashimoto,et al.  High frequency oscillations in early cortical somatosensory evoked potentials. , 1997, Electroencephalography and clinical neurophysiology.

[17]  P. Rossini,et al.  Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application. Report of an IFCN committee. , 1994, Electroencephalography and clinical neurophysiology.

[18]  M. Frye,et al.  Implications of Kindling And Quenching For the Possible Frequency Dependence Of rTMS , 1997, CNS Spectrums.

[19]  E. Ringelstein,et al.  Changing cortical excitability with low-frequency transcranial magnetic stimulation can induce sustained disruption of tactile perception , 2003, Biological Psychiatry.

[20]  G Curio,et al.  High-frequency (600 Hz) SEP activities originating in the subcortical and cortical human somatosensory system. , 1997, Electroencephalography and clinical neurophysiology.