An Electrophysiological Study of Chord Progression Cognition
Music conveys messages, and as every system able to transmit a message through time and space, music structure must follow precise rules in order to carry the correct meaning. The earliest electrophysiological evidence for precise structure in music was pointed out by Stefan Koelsch Tomas Gunter, and Angela D.Friederici in their 2000 study called "Brain Indices of Music Processing:'Nonmusicians' are Musical". This study pointed out how a violation to a typical tonal chord progression, V-Neap instead of V-I, elicited a brain response similar in nature to the Early Left Anterior Negativity (ELAN), which is elicited when the syntax of a sentence is not correct "Beware of the dog the in cage" . This 2000 study named this music-generated chord progression the Early Right Anterior Negativity (ERAN) for its right lateralization, a opposed to the left lateralization of the ELAN.
After the publication of this paper, several papers have focused on studying the ERAN and its features when elicited in musicians vs non-musicians, and also in its potential elicitation by using chord relationships other than V-Neap, melodies, and the effects of putting the violating motion at different time points of the musical flow.
 Koelsch, S., Gunter, T., Friederici, A., & Schröger, E. (2000). Brain indices of music processing:“nonmusicians” are musical. Cognitive Neuroscience, Journal of, 12(3), 520-541.