title: Implicit learning of predictable sound sequences modulates human brain responses at different levels of the auditory hierarchy.
abstract: Deviant stimuli, violating regularities in a sensory environment, elicit the mismatch negativity (MMN), largely described in the Event-Related Potential literature. While it is widely accepted that the MMN reflects more than basic change detection, a comprehensive description of mental processes modulating this response is still lacking. Within the framework of predictive coding, deviance processing is part of an inference process where prediction errors (the mismatch between incoming sensations and predictions established through experience) are minimized. In this view, the MMN is a measure of prediction error, which yields specific expectations regarding its modulations by various experimental factors. In particular, it predicts that the MMN should decrease as the occurrence of a deviance becomes more predictable. We conducted a passive oddball EEG study and manipulated the predictability of sound sequences by means of different temporal structures. Importantly, our design allows comparing mismatch responses elicited by predictable and unpredictable violations of a simple repetition rule and therefore departs from previous studies that investigate violations of different time-scale regularities. We observed a decrease of the MMN with predictability and interestingly, a similar effect at earlier latencies, within 70 ms after deviance onset. Following these pre-attentive responses, a reduced P3a was measured in the case of predictable deviants. We conclude that early and late deviance responses reflect prediction errors, triggering belief updating within the auditory hierarchy. Beside, in this passive study, such perceptual inference appears to be modulated by higher-level implicit learning of sequence statistical structures. Our findings argue for a hierarchical model of auditory processing where predictive coding enables implicit extraction of environmental regularities.
authors.affiliation: Lyon Neuroscience Research Center, CRNL, INSERM, U1028 - CNRS, UMR5292, Brain Dynamics and Cognition Team Lyon, France ; University Lyon 1 Lyon, France ; MEG Department, CERMEP Imaging Center Lyon, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Lecaignard
authors.affiliation: Lyon Neuroscience Research Center, CRNL, INSERM, U1028 - CNRS, UMR5292, Brain Dynamics and Cognition Team Lyon, France ; University Lyon 1 Lyon, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bertrand
authors.affiliation: MEG Department, CERMEP Imaging Center Lyon, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Gimenez
authors.affiliation: Lyon Neuroscience Research Center, CRNL, INSERM, U1028 - CNRS, UMR5292, Brain Dynamics and Cognition Team Lyon, France ; University Lyon 1 Lyon, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Mattout
authors.affiliation: Lyon Neuroscience Research Center, CRNL, INSERM, U1028 - CNRS, UMR5292, Brain Dynamics and Cognition Team Lyon, France ; University Lyon 1 Lyon, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Caclin
keywords: EEG; P3a; auditory regularity; early deviance response; mismatch negativity; predictive coding