Biology subjects

Gorina-Careta, N.

Publications and source records attributed to Gorina-Careta, N..

3 recordsLinked to original sources

bioRxiv2024

Bilingual Exposure and Sex Shape Developmental Trajectories of Brain Responses to Speech-Sound Features in Infants

As the auditory brain becomes functional during the third trimester of pregnancy, both biological and environmental processes begin shaping its maturation, influencing how speech sounds are perceived. Biological factors, such as sex, introduce early genetic differences, while environmental experiences, like bilingualism, modulate the auditory input that infants receive. Although existing research highlights the impact of sex and bilingualism on the development of speech perception, the neural mechanisms remain unclear. In this study, we recorded frequency-following responses (FFRs) longitudinally, at birth, six months, and twelve months of age in 73 infants exposed to varying degrees of bilingual input. We modeled the developmental trajectories for neural encoding of voice pitch and speech formant structure, finding significant maturation during the first six months, followed by stabilization through the first year. Distinct developmental patterns emerged as a function of sex and bilingualism, revealing their influence on neural attunement to key speech-sound features. Bilingual exposure notably predicted lower neural pitch encoding values at six months, but higher values by twelve months. A positive effect of bilingualism on speech formant encoding was observed throughout the first year. These findings reveal how biological and environmental factors contribute to individual variability in early auditory development and speech acquisition. HighlightsO_LIBilingualism and sex impact early developmental trajectories in neural speech encoding C_LIO_LIResults suggest a female advantage in early neural encoding of speech-sound features C_LIO_LIBilingual exposure positively modulates infant neural speech encoding C_LI

developmental biology↗

bioRxiv2024

Exposure to bilingual or monolingual maternal speech during pregnancy affects the neurophysiological encoding of speech sounds in neonates differently

Exposure to maternal speech during the prenatal period shapes speech perception and linguistic preferences, allowing neonates to recognize stories heard frequently in utero and demonstrating an enhanced preference for their mothers voice and native language. Yet, with a high prevalence of bilingualism worldwide, it remains an open question whether monolingual or bilingual maternal speech during pregnancy influence differently the fetus neural mechanisms underlying speech sound encoding. In the present study, the frequency-following response (FFR), an auditory evoked potential that reflects the complex spectrotemporal dynamics of speech sounds, was recorded to a two-vowel /oa/ stimulus in a sample of 131 healthy term neonates within the 1-3 days after birth. Newborns were divided into two groups according to maternal language usage during the last trimester of gestation (monolingual; bilingual). Spectral amplitudes and spectral signal-to-noise ratios (SNR) at the stimulus fundamental (F0) and first formant (F1) frequencies of each vowel were respectively taken as measures of pitch and formant structure neural encoding. Our results reveal that while spectral amplitudes at F0 did not differ between groups, neonates from bilingual mothers exhibited a lower spectral SNR. Additionally, monolingually exposed neonates exhibited a higher spectral amplitude and SNR at F1 frequencies. We interpret our results under the consideration that bilingual maternal speech, as compared to monolingual, is characterized by a greater complexity in the speech sound signal, rendering newborns from bilingual mothers more sensitive to a wider range of speech frequencies without generating a particularly strong response at any of them. Our results contribute to an expanding body of research indicating the influence of prenatal experiences on language acquisition and underscore the necessity of including prenatal language exposure in developmental studies on language acquisition, a variable often overlooked yet capable of influencing research outcomes.

neuroscience↗

bioRxiv2023

Longitudinal trajectories of the neural encoding mechanisms of speech-sound features during the first year of life

Infants quickly recognize the sounds of their mother language, perceiving the spectrotemporal acoustic features of speech. However, the underlying neural machinery remains unclear. We used an auditory evoked potential termed frequency-following response (FFR) to unravel the neural encoding maturation for two speech sound characteristics: voice pitch and temporal fine structure. The FFR was elicited by a two-vowel stimulus (/oa/) in a sample of 41 healthy-term neonates, tested at birth and retested at the ages of six and twelve months. Results revealed a reduction in neural phase-locking time to the stimulus envelope from birth to six months, remaining stable thereafter. While neural encoding of voice pitch remained consistent, temporal fine structure encoding matured rapidly from birth to six months, without further improvement from this age onwards. Results highlight the critical importance of the first six months in the maturation of neural encoding mechanisms, crucial for phoneme discrimination during early language acquisition.

neuroscience↗