Neurophysiological techniques in the study of the excitability, connectivity, and plasticity of the human brain

There is increasing evidence to support the concept that brain plasticity involves distinct functional and structural components, each requiring several cellular mechanisms operating at different time scales, synaptic loci, and developmental phases within an extremely complex framework. However, the precise relationship between functional and structural components of brain plasticity/connectivity phenomena is still unclear and its explanation represents a major challenge within modern neuroscience. The key feature of neurophysiological techniques described in this review paper is their pivotal role in tracking temporal dynamics and inner hierarchies of brain functional and effective connectivities, possibly clarifying some crucial issues underlying brain plasticity. Taken together, the findings presented in this review open an intriguing new field in neuroscience investigation and are important for the adoption of neurophysiological techniques as a tool for basic research and, in future, even for clinical diagnostics purposes.