Cortical Excitability, Plasticity and Oscillations in Major Psychiatric Disorders: A Neuronavigated TMS-EEG Based Approach

Developing biomarkers for psychiatric disorders represents a major challenge. Indeed, the identification of dependable brain-based measures, such as those derived from electrophysiological techniques, would represent a key step toward better profiling of patients with major psychiatric disorders. A principled neurophysiological approach would also deepen our understanding of the physiopathology and inform therapeutic decisions. The present chapter focuses on a neurophysiological technique, based on the combination of neuronavigated Transcranial Magnetic Stimulation and Electroencephalography (TMS-EEG), which allows probing directly and non-invasively cortical excitability, plasticity as well as the fundamental oscillatory properties of thalamocortical circuits. Since these parameters are often altered in psychiatric disorders, neuronavigated TMS-EEG may be in a suitable position to provide neurophysiological objective measures to support the diagnosis of psychiatric disorders, to highlight their physiopathological underpinnings, and to objectively assess the efficacy of treatment options

Crystalline Structure, Defect Chemistry and Room Temperature Colossal Permittivity of Nd-doped Barium Titanate

Dielectric materials with high permittivity are strongly demanded for various technological applications. While polarization inherently exists in ferroelectric barium titanate (BaTiO(3)), its high permittivity can only be achieved by chemical and/or structural modification. Here, we report the room-temperature colossal permittivity (~760,000) obtained in xNd: BaTiO(3) (x = 0.5 mol%) ceramics derived from the counterpart nanoparticles followed by conventional pressureless sintering process. Through the systematic analysis of chemical composition, crystalline structure and defect chemistry, the substitution mechanism involving the occupation of Nd(3+) in Ba(2+) -site associated with the generation of Ba vacancies and oxygen vacancies for charge compensation has been firstly demonstrated. The present study serves as a precedent and fundamental step toward further improvement of the permittivity of BaTiO(3)-based ceramics