Brain-correlates of processing local dependencies within a statistical learning paradigm

Abstract

Statistical learning refers to the implicit mechanism of extracting regularities in our environment. Numerous studies have investigated the neural basis of statistical learning. However, how the brain responds to violations of auditory regularities based on prior (implicit) learning requires further investigation. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of processing events that are irregular based on learned local dependencies. A stream of consecutive sound triplets was presented. Unbeknown to the subjects, triplets were either (a) standard, namely triplets ending with a high probability sound or, (b) statistical deviants, namely triplets ending with a low probability sound. Participants (n = 33) underwent a learning phase outside the scanner followed by an fMRI session. Processing of statistical deviants activated a set of regions encompassing the superior temporal gyrus bilaterally, the right deep frontal operculum including lateral orbitofrontal cortex, and the right premotor cortex. Our results demonstrate that the violation of local dependencies within a statistical learning paradigm does not only engage sensory processes, but is instead reminiscent of the activation pattern during the processing of local syntactic structures in music and language, reflecting the online adaptations required for predictive coding in the context of statistical learning.

Disentangling Hierarchical and Sequential Computations during Sentence Processing

“…However, hierarchical structure processing could co-exist with simpler, shallower, and perhaps evolutionarily older mechanism for local, word-by-word predictions. Indeed, the co-existence of two distinct mechanisms was already identified in the case of the processing of sequences of nonlinguistic items (23)(24)(25)(26)(27)(28)(29). Specifically, using the Local-Global Paradigm, a variant of the oddball auditory paradigm, Bekinschtein et al (23) showed that transition-based (local) processing can be distinguished from that of chunking (global) and from possibly higher levels, each eliciting distinct violation signals in different brain areas and timings (30)(31)(32)(33)(34)(35).…”