Neuronal Mechanisms of Voice Control Are Affected by Implicit Expectancy of Externally Triggered Perturbations in Auditory Feedback

Oleg Korzyukov,Roozbeh Behroozmand,Charles R Larson,Lindsey Sattler,Ramesh Balasubramaniam

doi:10.1371/journal.pone.0041216

Oleg Korzyukov, Roozbeh Behroozmand + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0041216

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Journal: PloS one	Publication Date: Jul 17, 2012
Citations: 28	License type: CC BY 4.0

Affiliation: Northwestern University

Abstract

Accurate vocal production relies on several factors including sensory feedback and the ability to predict future challenges to the control processes. Repetitive patterns of perturbations in sensory feedback by themselves elicit implicit expectations in the vocal control system regarding the timing, quality and direction of perturbations. In the present study, the predictability of voice pitch-shifted auditory feedback was experimentally manipulated. A block of trials where all pitch-shift stimuli were upward, and therefore predictable was contrasted against an unpredictable block of trials in which the stimulus direction was randomized between upward and downward pitch-shifts. It was found that predictable perturbations in voice auditory feedback led to a reduction in the proportion of compensatory vocal responses, which might be indicative of a reduction in vocal control. The predictable perturbations also led to a reduction in the magnitude of the N1 component of cortical Event Related Potentials (ERP) that was associated with the reflexive compensations to the perturbations. We hypothesize that formation of expectancy in our study is accompanied by involuntary allocation of attentional resources occurring as a result of habituation or learning, that in turn trigger limited and controlled exploration-related motor variability in the vocal control system.

Highlights

In our everyday environment neuronal mechanisms that incorporate information about future states of the body or the environment appear to be critical for driving cognitive functions and behavior [1,2]
Results of the present study demonstrate that repetitive presentation of identical pitch-shifted voice auditory feedback stimuli leads to changes in the vocal control system that can be measured at the behavioral and neural levels
Such stimulation led to a greater percentage of ‘‘following’’ vocal responses and smaller amplitude N1 Event Related Potentials (ERP) responses

Summary

Introduction

In our everyday environment neuronal mechanisms that incorporate information about future states of the body or the environment appear to be critical for driving cognitive functions and behavior [1,2]. For example analogous to Pavlovian conditioning, involuntary learning within the perceptual domain creates expectations about future events without an option to influence them. Perceptual cognizance of more complex sensory inputs such as speech and music are critically linked to the extraction of regular patterns from auditory input. It was recently hypothesized that comprehension of complex linguistic information such as syntactic structure depends on extraction of regular patterns from the speech signal and is mediated by the pre-supplementary motor area – basal ganglia circuit [7]

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