Abstract

In vivo neurophysiology in humans has experienced a surge in novel experimental designs thanks to the introduction of non-invasive transcranial brain stimulation (NTBS) protocols. A drawback of such protocols is represented by the high interindividual variability that negatively impacts the replicability of both scientific and clinical trials. With a prospective clinical application in mind, my colleagues and I first developed a safe NTBS protocol that took inter-individual anatomical and functional differences into account. The application of this novel protocol called individualized paired-associative stimulation (iPAS) on the primary motor cortex in healthy volunteers resulted in a trend level increase in post-stimulation neuronal excitability. NTBS are generally characterized by a favorable side-effects profile, however, in clinical practice, side-effects like vertigo or dizziness are often reported by patients. In particular, patients affected by schizophrenia are generally more vulnerable to autonomic dysfunction than the general population. The aim of the second research project presented here was to better investigate the impact of a NTBS protocol called repetitive transcranial magnetic stimulation (rTMS) on autonomic function in a cohort of patients affected by schizophrenia. In summary, we under-went a secondary analysis of the largest to date randomized multicenter con-trolled trial involving schizophrenia patients investigating the effect on autonomic function of rTMS delivered to the dorsolateral prefrontal cortex. We were able to report a lack of significant changes in heart rate and blood pres-sure in individuals receiving rTMS compared to individuals receiving a sham stimulation. Thus, rTMS appears to be a safe technique even in more vulnerable populations. By addressing two crucial aspects of NTBS, namely interindividual variability and safety both works lay the foundation for a further investigation of potential plasticity-augmenting effects of iPAS in schizophrenia patients, where currently effective therapeutic options are limited and more research is urgently needed.