Perceived Closeness and Autistic Traits Modulate Interpersonal Vocal Communication.

Vocal modulation is a critical component of interpersonal communication. It not only serves as a dynamic and flexible tool for self-expression and linguistic information but also plays a key role in social behavior. Variation in vocal modulation can be driven by individual traits of interlocutors as well as factors relating to the dyad, such as the perceived closeness between interlocutors. In this study we examine both of these sources of variation. At an individual level, we examine the impact of autistic traits, since lack of appropriate vocal modulation has often been associated with Autism Spectrum Disorders. At a dyadic level, we examine the role of perceived closeness between interlocutors on vocal modulation. The study was conducted in three separate samples from India, Italy, and the UK. Articulatory features were extracted from recorded conversations between a total of 85 same-sex pairs of participants, and the articulation space calculated. A larger articulation space corresponds to greater number of spectro-temporal modulations (articulatory variations) sampled by the speaker. Articulation space showed a positive association with interpersonal closeness and a weak negative association with autistic traits. This study thus provides novel insights into individual and dyadic variation that can influence interpersonal vocal communication.

Are you a good mimic? Neuro-acoustic signatures for speech imitation ability.

We investigated individual differences in speech imitation ability in late bilinguals using a neuro-acoustic approach. One hundred and thirty-eight German-English bilinguals matched on various behavioral measures were tested for "speech imitation ability" in a foreign language, Hindi, and categorized into "high" and "low ability" groups. Brain activations and speech recordings were obtained from 26 participants from the two extreme groups as they performed a functional neuroimaging experiment which required them to "imitate" sentences in three conditions: (A) German, (B) English, and (C) German with fake English accent. We used recently developed novel acoustic analysis, namely the "articulation space" as a metric to compare speech imitation abilities of the two groups. Across all three conditions, direct comparisons between the two groups, revealed brain activations (FWE corrected, p < 0.05) that were more widespread with significantly higher peak activity in the left supramarginal gyrus and postcentral areas for the low ability group. The high ability group, on the other hand showed significantly larger articulation space in all three conditions. In addition, articulation space also correlated positively with imitation ability (Pearson's r = 0.7, p < 0.01). Our results suggest that an expanded articulation space for high ability individuals allows access to a larger repertoire of sounds, thereby providing skilled imitators greater flexibility in pronunciation and language learning.

Picture-naming in patients with left frontal lobe tumor - a functional neuroimaging study.

The objective of this study was to investigate behavioral performance as well as cortical activation patterns while picture-naming, in patients with left frontal lobe tumor prior to surgery. Functional magnetic resonance imaging was used to compare behavior and brain activations while 10 patients with a tumor in the left frontal lobe and 9 controls, named aloud simple pictures presented in a block design inside a 3 T Philips Achieva scanner. Evaluations of task performance included naming accuracy and articulation time. Behaviorally, patients took significantly longer to articulate picture names but naming accuracy was preserved. Analysis of brain activations showed differences only in the frontal regions of the cortical network. In particular, while the frontal activations in the control population were focused and localized in the left inferior orbito-frontal gyrus, in patients the frontal network was distributed and included a significantly greater number of clusters that were distributed in homologous or near homologous areas of the (orbito-frontal gyrus) left and/or right hemisphere of the frontal lobe. Our results suggest that in patients with a left frontal lobe tumor the process of naming simple pictures is preserved but the cortical network of activation in the frontal region is altered and is distributed in the frontal regions of both hemispheres.