Combining transcranial brain stimulation and PET/SPECT molecular imaging

Transcranial brain stimulation (TMS) was introduced in 1985 by Barker and his colleagues. Since then, further improvements in technology have allowed additional applications and new stimulation protocols. In the last decade, while the use of TMS has expanded enormously in basic science as well as in the clinical scenario, the underlying neurophysiological or neurochemical mechanisms are still not fully understood. Positron emission tomography (PET) and single-photon emission computerized tomography (SPECT) are neuroimaging modalities utilized to investigate brain functions. In spite of their lower spatial and time resolution compared with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), PET/SPECT have helped to elucidate some of the neurochemical mechanisms and neural plastic changes associated with TMS. In this chapter, we will provide an overview of these techniques, describing methodological details and application of TMS-PET/SPECT imaging in basic and clinical studies.