Seizure models: anticonvulsant effects of ECT and rTMS.

1. A variety of enzymes, peptides, neurotrophic factors and their receptors show complex cascades of alterations with amygdala-kindled seizure progression; some represent compensatory adaptations that could become new targets of therapeutics. 2. Non-convulsant brain stimulation with repetitive transcranial magnetic stimulation (rTMS) may be able to engage some of the neuro-adaptive effects of ECT without the necessity of inducing a seizure. 3. Data from preclinical and clinical studies raise the possibility that non-convulsant stimulation achieved by high or low frequency rTMS may be able to alter neurotransmitters, neuropeptides, and neurotrophic factors, leading to frequency- and region-dependent changes in neural excitability. 4. Individual depressed patients show differential responses to two weeks high vs. low frequency rTMS, as revealed by the inverse correlation of degree of improvement in depression achieved by these two frequencies. 5. Preliminary data from rTMS and positron emission tomography (PET) studies reveal moderately sustained differential effects of rTMS frequency on regional cerebral neural activity in depressed patients. 6. These data suggest the possibility that an individual's level of baseline rCBF or rCMRglu on PET would help predict which rTMS frequency might be the most appropriate treatment for their depression.