Temporal regularity facilitates higher-order sensory predictions in fast auditory sequences.

Does temporal regularity facilitate prediction in audition? To test this, we recorded human event-related potentials to frequent standard tones and infrequent pitch deviant tones, pre-attentively delivered within isochronous and anisochronous (20% onset jitter) rapid sequences. Deviant tones were repeated, either with high or low probability. Standard tone repetition sets a first-order prediction, which is violated by deviant tone onset, leading to a first-order prediction error response (Mismatch Negativity). The response to highly probable deviant repetitions is, however, attenuated relative to less probable repetitions, reflecting the formation of higher-order sensory predictions. Results show that temporal regularity is required for higher-order predictions, but does not modulate first-order prediction error responses. Inverse solution analyses (Variable Resolution Electrical Tomography; VARETA) localized the error response attenuation to posterior regions of the left superior temporal gyrus. In a control experiment with a slower stimulus rate, we found no evidence for higher-order predictions, and again no effect of temporal information on first-order prediction error. We conclude that: (i) temporal regularity facilitates the establishing of higher-order sensory predictions, i.e. 'knowing what next', in fast auditory sequences; (ii) first-order prediction error relies predominantly on stimulus feature mismatch, reflecting the adaptive fit of fast deviance detection processes.