FMRI and acoustic analyses reveal neural correlates of gestural complexity and articulatory effort within bilateral inferior frontal gyrus during speech production. (September 2019)

• Record Type: Journal Article
• Authors: Pützer, Manfred; Moringlane, Jean Richard; Sikos, Les; Reith, Wolfgang; Krick, Christoph M.
• Is Part Of: Neuropsychologia. Volume 132(2019)
• Publication Date: 2019-09
• Subjects: fMRI -- Speech production -- Acoustic analysis -- IFG -- Gestural complexity -- Articulatory effort; Neuropsychology -- Periodicals; Neurology -- Periodicals; Psychophysiology -- Periodicals; Neuropsychologie -- Périodiques; Neuropsychology; Periodicals; Electronic journals; 616.8
• DOI: 10.1016/j.neuropsychologia.2019.107129
• Languages: English
• ISSNs: 0028-3932

Abstract

Abstract: In an event-related fMRI study of overt speech production, we investigated the relationship between gestural complexity and underlying brain activity within bilateral inferior frontal gyrus (IFG). We operationalized gestural complexity as the number of active articulatory tiers (glottal, oral, nasal) and the degree of fine-grained temporal coordination between tiers (low, high). Forty-three neurotypical participants produced three types of highly- frequent non-word CV-syllable sequences, which differ systematically in gestural complexity (simple: ['dadada], intermediate: ['tatata], complex: ['nanana]). Comparing blood oxygen level-dependent (BOLD) responses across complexity conditions revealed that syllables with greater gestural complexity elicited increased activation patterns. Moreover, when durational parameters were included as covariates in the analyses, significant effects of articulatory effort were found over and above the effects of complexity. The results suggest that these differences in BOLD-response reflect the differential contribution of articulatory mechanisms that are required to produce phonologically distinct speech sounds. Highlights: Gestural complexity is correlated with activation in bilateral IFG during production. Effects of gestural complexity can be distinguished from articulatory effort. Results suggest bilateral IFG supports mechanisms that distinguish speech sounds. Findings contribute to our understanding of the speech motor execution system.