The P600 is an event-related potential (ERP) component, or peak in electrical brain activity measured by electroencephalography (EEG). It is a language-relevant ERP component and is thought to be elicited by hearing or reading grammatical errors and other syntactic anomalies. Therefore, it is a common topic of study in neurolinguistic experiments investigating sentence processing in the human brain. The P600 can be elicited in both visual (reading) and auditory (listening) experiments, and is characterized as a positive-going deflection with an onset around 500 milliseconds after the stimulus that elicits it; it often reaches its peak around 600 milliseconds after presentation of the stimulus (hence its name), and lasts several hundred milliseconds. In other words, in the EEG waveform it is a large peak in the positive direction, which starts around 500 milliseconds after the subject sees or hears a stimulus. It is typically thought of as appearing mostly on centro-parietal electrodes (i.e., over the posterior part of the center of the scalp), but frontal P600s have also been observed in several studies. In EEG, however, this distribution at the scalp does not mean the P600 is coming from that part of the brain; a 2007 study using magnetoencephalography (MEG) speculates that the generators of the P600 are in the posterior temporal lobe, behind Wernicke's area. The P600 was first reported by Lee Osterhout and Phillip Holcomb in 1992. It is also sometimes called the syntactic positive shift (SPS), since it has a positive polarity and is usually elicited by syntactic phenomena. (en)