Neurophysiology may be a branch of physiology and neuroscience that's concerned with the study of the functioning of the systema nervosum . Neurophysiology or electrodiagnostic testing refers to specialised investigations utilized in the diagnosis and prognosis of peripheral systema nervosum disorders. There are two main techniques: 1. Nerve Conduction Studies 2. Electromyography (EMG). Neurophysiology is the study of the functional properties of neurons, glia, and networks. Historically it has been dominated by electrophysiology—the electrical recording of neuronal events ranging from the molar (the electroencephalogram, EEG) to the cellular (intracellular recording of the properties of single neurons). However, as the neuron is an electrochemical machine, it is impossible to separate electrical events from the biochemical and molecular processes that bring them about. Thus neurophysiologists today use techniques from chemistry (calcium imaging), physics (functional magnetic resonance imaging, fMRI), and molecular biology (site directed mutations) to study brain function. As we shall see, the use of in vitro techniques has facilitated all aspects of modern neurophysiology and can be fairly stated to have permitted many of them. In vitro neurophysiology has its origins in the biochemical studies on energy metabolism by Henry McIlwain and others in the 1950s (McIlwain 1984). They cut brain and other tissue into thin (<0.5 mm) slices, which were kept alive in vials of artificial cerebrospinal fluid (ACSF) from which was extracted substances of interest.