An event-related potential (ERP) is any stereotyped electrophysiological response to an internal or external stimulus. More simply, it is any measured brain response that is directly the result of a thought or perception. Electrophysiology is the study of the electrical properties of biological cells and tissues. ... In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... Thought or thinking is a mental process which allows beings to model the world, and so to deal with it effectively according to their goals, plans, ends and desires. ... The word, Perception, comes from the latin word, capere, meaning to take, the prefix per- means completely. In psychology and the cognitive sciences, perception is the process of acquiring, interpreting, selecting, and organizing sensory information. ...

Measurement

ERPs can be reliably measured using electroencephalography (EEG), a procedure that measures electrical activity of the brain through the skull and scalp. As the EEG reflects thousands of simultaneously ongoing brain processes, the brain response to a certain stimulus or event of interest is usually not visible in the EEG. One of the most robust features of the ERP response is a response to unpredictable stimuli. This response-known as the P300 (or simply "P3")-manifests as a positive deflection in voltage approximately 300 milliseconds after the stimulus is presented. Reliability concerns quality or consistency. ... Electroencephalography is the neurophysiologic exploration of the electrical activity of the brain by the application of electrodes to the scalp. ... Lightning strikes during a night-time thunderstorm. ... A hippopotamus skull A skull, or cranium, is a bony structure of Craniates which serves as the general framework for a head. ... The scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly. ... The term Ongoing brain activity is used in electroencephalography and magnetoencephalography for those signal components that are not associated with the processing of a stimulus or the occurrence of specific other events, such as moving a body part, i. ... The P300 is a neural evoked potential component of the electroencephalogram (EEG). ... Josephson junction array chip developed by NIST as a standard volt. ... Look up second in Wiktionary, the free dictionary. ...

In actual recording situations, it is difficult to see an ERP after the presentation of a single stimulus. Rather the most robust ERPs are seen after many dozens or hundreds of individual presentations are averaged together. This technique cancels out noise in the data allowing only the voltage response to the stimulus to stand out clearly. In mathematics, an average or central tendency of a set (list) of data refers to a measure of the middle of the data set. ... Electronic noise In any electronic circuit, there exist random variations in current or voltage caused by the random movement of the electrons carrying the current as they are jolted around by thermal energy. ...

While evoked potentials reflect the processing of the physical stimulus, event-related potentials are caused by the "higher" processes, that might involve memory, expectation, attention, or changes in the mental state, among others. This article does not cite its references or sources. ... In psychology, memory is the ability of an organism to store, retain, and subsequently recall information. ... expectation in the context of probability theory and statistics, see expected value. ... Look up Attention in Wiktionary, the free dictionary. ...

Clinical ERP

Physicians and neurologists will sometimes use a flashing visual checkerboard stimulus to test for any damage or trauma in the visual system. In a healthy person, this stimulus will elicit a strong response over the primary visual cortex located in the occipital lobe in the back of the brain. The Doctor by Samuel Luke Fildes This article is about the term physician, a type of doctor; for other uses of the word doctor see Doctor (disambiguation). ... Neurology is a branch of medicine dealing with disorders of the nervous system. ... Look up vision in Wiktionary, the free dictionary. ... Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ... The occipital lobe is the visual processing center of the mammalian brain. ...

Research ERP

Experimental psychologists and neuroscientists have discovered many different stimuli, such as erotica (in a Washington University study), to elicit reliable EEG ERPs from participants. The timing of these responses is thought to provide a measure of the timing of the brain's communication or time of information processing. For example, in the checkerboard paradigm described above, in healthy participants the response of the visual cortex is around 150-200ms. This would seem to indicate that this is the amount of time it takes for the transduced visual stimulus to reach the cortex after light first enters the eye. Alternatively, the P300 response occurs at around 300ms regardless of the stimulus presented: visual, tactile, auditory, olfactory, gustatory, etc. Because of this general invariance in regard to stimulus type, this ERP likely reflects a higher cognitive response to new stimuli. Experimental psychology is an approach to psychology that treats it as one of the natural sciences, and therefore assumes that it is susceptible to the experimental method. ... Drawing of the cells in the chicken cerebellum by S. Ramón y Cajal Neuroscience is a scientific discipline that studies the structure, function, development, genetics, biochemistry, physiology, pharmacology, and pathology of the nervous system. ... It has been suggested that this article or section be merged with Erotic art. ... The telencephalon (te-len-seff-a-lon) is the technical name for a large region within the brain which is attributed many functions, which some groups would class as unique features which make humans stand out from other species. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength [citation needed]. The elementary particle that defines light is the photon. ... Closeup of a blue-green human eye. ... This article or section does not cite its references or sources. ... Sound is a disturbance of mechanical energy that propagates through matter as a wave. ... Olfaction, the sense of odor (smell), is the detection of chemicals dissolved in air (or in water, by animals that live under water). ...

See also

• Evoked potential
• Induced activity
• P300
• N400