High-density intracranial recordings reveal a distinct site in anterior dorsal precentral cortex that tracks perceived speech.

Various brain regions are implicated in speech processing, and the specific function of some of them is better understood than others. In particular, involvement of the dorsal precentral cortex (dPCC) in speech perception remains debated, and attribution of the function of this region is more or less restricted to motor processing. In this study, we investigated high-density intracranial responses to speech fragments of a feature film, aiming to determine whether dPCC is engaged in perception of continuous speech. Our findings show that dPCC exhibited preference to speech over other tested sounds. Moreover, the identified area was involved in tracking of speech auditory properties including speech spectral envelope, its rhythmic phrasal pattern and pitch contour. DPCC also showed the ability to filter out noise from the perceived speech. Comparing these results to data from motor experiments showed that the identified region had a distinct location in dPCC, anterior to the hand motor area and superior to the mouth articulator region. The present findings uncovered with high-density intracranial recordings help elucidate the functional specialization of PCC and demonstrate the unique role of its anterior dorsal region in continuous speech perception.

Differential associations between psychosocial stress and obesity among Ghanaians in Europe and in Ghana: findings from the RODAM study.

PURPOSE: Psychosocial stress is associated with obesity in some populations, but it is unclear whether the association is related to migration. This study explored associations between psychosocial stress and obesity among Ghanaian migrants in Europe and non-migrant Ghanaians in Ghana. METHODS: Cross-sectional data from the RODAM study were used, including 5898 Ghanaians residing in Germany, the UK, the Netherlands, rural Ghana, and urban Ghana. Perceived discrimination, negative life events and stress at work or at home were examined in relation to body mass index (BMI) and waist circumference (WC). Linear regression analyses were performed separately for migrants and non-migrants stratified by sex. RESULTS: Perceived discrimination was not associated with BMI and WC in both migrants and non-migrants. However, negative life events were positively associated with BMI (ß = 0.78, 95% CI 0.34-1.22) and WC (ß = 1.96, 95% CI 0.79-3.12) among male Ghanaian migrants. Similarly, stress at work or at home was positively associated with BMI (ß = 0.28, 95% CI 0.00-0.56) and WC (ß = 0.84, 95% CI 0.05-1.63) among male Ghanaian migrants. Among non-migrant Ghanaians, in contrast, stress at work or at home was inversely associated with BMI and WC in both males (ß = - 0.66, 95% CI - 1.03 to - 0.28; ß = - 1.71 95% CI - 2.69 to - 0.73, respectively) and females (ß = - 0.81, 95% CI - 1.20 to - 0.42; ß = - 1.46, 95% CI - 2.30 to - 0.61, respectively). CONCLUSIONS: Negative life events and stress at work or at home are associated with increased body weight among male Ghanaians in European settings, whereas stress at work or at home is associated with reduced body weight among Ghanaians in Ghana. More work is needed to understand the underlying factors driving these differential associations to assist prevention efforts.