Presentations

Abstract

The neural infrastructure for sentence production and comprehension has been found to be mostly shared. The same regions are engaged during speaking and listening, with some differences in their loading depending on modality (Giglio et al., 2022). In this fMRI study (n=40), we investigated whether modality affects the connectivity between inferior frontal and temporal regions, previously found to be involved in syntactic processing across modalities, and with the cerebellum, which has been historically linked with motor aspects of production. Participants produced or listened to word sequences of increasing constituent size. We found that constituent size reliably increased the connectivity between the inferior frontal gyrus and the posterior temporal lobe in both modalities. Preliminary cerebellar results suggest that different sub-regions presented different patterns of connectivity. Connectivity between Lobule VI and (pre)motor regions was increased during production relative to comprehension. Connectivity between Crus I/II and fronto-temporal regions was instead increased as a function of constituent size, and in particular during production. These results thus show that the connectivity between fronto-temporal regions is upregulated for syntactic structure building in both sentence production and comprehension, while cortico-cerebellar connectivity is enhanced both in response to syntactic processing and during production.

Abstract

Monitoring auditory feedback is important for fluent speech production as it enables correction of vocalization errors. Influence of auditory feedback is best illustrated by manipulating it during speech production. A common temporal manipulation technique is delaying auditory feedback (DAF), which disrupts speech fluency, and a common spectral manipulation technique is perturbing the pitch of auditory feedback, which elicits vocal changes. We aimed to understand whether there is a correlation between sensitivity to temporal versus spectral manipulations of auditory feedback. We collected data from 40 participants. In the DAF task, participants repeated sentences, and auditory feedback was presented with 0 or 200ms delay. In the pitch perturbation task, participants phonated the vowel /a/ for 4 seconds and pitch of the auditory feedback was shifted by ±100 or ±200 cents.Voice recordings were analyzed using LME models to test the effects of feedback manipulations. We found that DAF significantly prolonged articulation duration and increased both voice pitch and intensity. Additionaly we found that large pitch shifts elicited less compensatory responses. There was a large individual variability in sensitivity to feedback manipulations for both tasks, however there was no correlation between the sensitivity profiles between tasks, suggesting that these features are processed differently.