EEG and MEG markers of vocal inhibition in fluent and non-fluent speakers

Overactivation of the right inferior frontal gyrus, an area of the brain that underpins voluntary arrest of action, has been associated with stuttering. While there has been much research conducted on manual response inhibition, very few studies have examined vocal response inhibition and to date, no study has examined the temporal neurodynamics of vocal inhibition. Therefore, the first part of the present study identified, in a group of control participants, the temporal neural correlates of vocal response inhibition by recording electroencephalographic activity during a modified version of the stop signal task. Behavioural results showed that participants were able to inhibit a vocal response within approximately 324 ms. Analysis of ERPs revealed that a positive component around 324 ms was significantly larger in amplitude during successfully stopped trials compared to in an ignore condition. The second part of this study applied the methodology of the first part to a group of stuttering participants in a magnetoencephalographic (MEG) study. The results of this allow us to examine the temporal neurodynamics of vocal response inhibition in stutterers and to examine these in relation to the brain structures known to exhibit functional activation anomalies in stuttering.1 page(s