Waitt, A. | bioRxiv Science

bioRxiv2026

Neural discrimination of emotional prosody in natural sentences in 2- to 3-month-old infants using OPM-MEG

From birth, infants are sensitive to the emotional prosody of speech, yet it remains unclear when the developing brain discriminates emotions conveyed by natural spoken sentences. Here, we recorded brain activity with optically pumped magnetometer magnetoencephalography (OPM-MEG) in 15 infants aged 2-3 months while they listened to semantically neutral sentences spoken with happy or angry prosody. Natural sentences elicited robust auditory evoked responses, with prominent components at 88, 216, 380 and 1,356 ms after sentence onset and sources centred on bilateral superior and middle temporal cortex. Time-resolved multivariate pattern analysis revealed that distributed neural activity discriminated recordings spoken with happy from angry prosody 346-454 ms after the onset of the prosodically prominent word (the first word carrying a pitch peak), despite no difference in global field power between conditions. This discrimination was transient, emerged before the end of the sentence, and was carried primarily by phase-locked delta-band activity, followed by later differences in induced alpha power. Angry prosody also delayed the late auditory response by approximately 15 ms with no detectable changes in amplitude. Our findings show that cortical responses to happy and angry prosody in natural speech differ by 2-3 months of age, and demonstrate that OPM-MEG combined with time-resolved decoding can reveal the temporal, spatial and spectral organisation of early emotional-prosody processing.

neuroscience↗

bioRxiv2025

Altered Motor Gamma Activity and Hemispheric Lateralisation Reflect Perinatal Maturity in Preterm Children during Motor Control

Preterm birth, defined as delivery before 37 weeks of gestation, is associated with differences in neurodevelopment and an increased likelihood of motor challenges that may persist throughout childhood. However, the neurophysiological correlates of these motor differences remain insufficiently understood. Oscillatory activity in the primary motor cortex is closely linked to motor execution, yet motor-related oscillations have rarely been examined in children born preterm. In this cross-sectional observational study, we investigated motor-related gamma oscillations in 5- to 7-year-old children using a child-customised magnetoencephalography system. Nineteen children born full-term and 18 children born preterm of comparable age performed a child-friendly dominant-hand finger movement task. Movement-related gamma activity was quantified from bilateral precentral gyrus regions used as anatomical proxies for the primary motor cortices. The preterm group showed longer mean response times and greater intra-individual response-time variability than the full-term group (P = 0.003 and P = 0.030, respectively). Contralateral gamma power was also lower in the preterm group (full-term: 59.89 {+/-} 28.87%; preterm: 37.97 {+/-} 25.82%; t(35) = 2.43, P = 0.020, Cohen's d = 0.80). A significant Group x Hemisphere interaction (F(1, 35) = 13.36, P < 0.001, partial 2 = 0.276) further indicated differences in the hemispheric organisation of gamma activity between groups. The gamma laterality index was also lower in children born preterm (full-term: 0.24 {+/-} 0.21; preterm: -0.11 {+/-} 0.37; t(26.4) = 3.51, P = 0.002, Cohen's d = 1.17), consistent with reduced contralateral dominance. Across the whole sample, greater contralateral gamma lateralisation was associated with higher scores on the Hand Movements subtest of the Kaufman Assessment Battery for Children ({rho} = 0.40, P = 0.014, false discovery rate-adjusted q = 0.042) and earlier independent walking ({rho} = 0.57, P < 0.001, q = 0.002). The association with independent walking was also observed within the preterm group ({rho} = 0.78, P < 0.001, q = 0.002). These findings suggest that reduced contralateral gamma power and reduced hemispheric lateralisation in children born preterm may reflect differences in the developmental organisation of motor cortical networks. This study provides new insight into motor cortical organisation and its relationship with motor development following preterm birth.

neuroscience↗