Psychophysiology is the branch of psychology that is concerned with the physiological bases of psychological processes. While psychophysiology was a general broad field of research in the 1960s and 1970s, it has now become quite specialized, and has branched into sub specializations such as social psychophysiology, cardiovascular psychophysiology, cognitive psychophysiology, and cognitive neuroscience. Some people have difficulty distinguishing a psychophysiologist from a physiological psychologist, two very different perspectives. Psychologists are interested in why we may fear spiders and physiologists may be interested in the input/output system of the amygdala. A psychophysiologist will attempt to link the two.
Psychophysiologists generally study the psychological/physiological link in intact human subjects. While early psychophysiologists almost always examined the impact of psychological states on physiological system responses, since the 1970s, psychophysiologists also frequently study the impact of physiological states and systems on psychological states and processes. It is this perspective of studying the interface of mind and body that makes psychophysiologists most distinct. Historically, most psychophysiologists tended to examine the physiological responses and organ systems innervated by the autonomic nervous system.
More recently, psychophysiologists have been equally, or potentially more, interested in the central nervous system, exploring cortical brain potentials such as the many types of event-related potentials (ERPs), brain waves, and utilizing advanced technology such as functional magnetic resonance imaging (fMRI), MRI, PET, MEG, and other neuroimagery techniques.