 In the field of experimental psychology, neuropsychology and psychobiology, the process of tracking and recording cerebrum-cortical electrical activity, and its combination with other values of psychomotor activity, enables the diagnosis of the emotional responses of an individual.Psycho-physiological states are assigned to different electrical values.These variations in electrical potential can be recorded with the use of contact electrodes; in most academic situations they are connected to a signal amplifier and an inkjet instrument that reacts to the variations of potential and amplitude of the input data.