The auditory novelty system: an attempt to integrate human and animal research

In this account, we attempt to integrate two parallel, but thus far, separate lines of research on auditory novelty detection: (1) human studies of EEG recordings of the mismatch negativity (MMN), and (2) animal studies of single-neuron recordings of stimulus-specific adaptation (SSA). The studies demonstrating the existence of novelty neurons showing SSA at different levels along the auditory pathway's hierarchy, together with the recent results showing human auditory-evoked potential correlates of deviance detection at very short latencies, that is, at 20-40 ms from change onset, support the view that novelty detection is a key principle that governs the functional organization of the auditory system. Furthermore, the generation of the MMN recorded from the human scalp seems to involve a cascade of neuronal processing that occurs at different successive levels of the auditory system's hierarchy.