Homeostatic plasticity of cerebral cortex. Examinations in healthy subjects and migraine patients

Evidence from animal data and slice preparations suggests that homeostatic mechanisms exist in order to keep cortical excitability within a physiologically useful range. Combining two different transcranial stimulation techniques, i.e. transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), we recently demonstrated in healthy subjects that a homeostatic-like mechanism could also be found non-invasively in the human motor cortex (M1). The amount and direction of rTMS-induced excitability changes, indexed by the amplitudes of motor evoked potentials (MEP), depended o…