This chapter provides an introduction to the neurophysiological foundations and hardware implementations of several critical neuroimaging and neurophysiological monitoring techniques. It enlightens readers about the principles and applications of electroencephalography (EEG), electrooculography (EOG), functional near-infrared spectroscopy (fNIRS), functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and functional ultrasound (fUS). Each section begins by explaining the neurobiological basis of the signals detected by these technologies, followed by a discussion on the specific hardware used, its configuration, and its operational nuances. The chapter aims to equip readers with a solid understanding of how these technologies function and their role in advancing our understanding of brain dynamics. This foundational knowledge is crucial for both beginners and seasoned practitioners in the fields of neuroscience and cognitive science, facilitating a deeper understanding of the methodological approaches used in current research.