Active auditory experience in infancy promotes brain plasticity in Theta and Gamma oscillations

Language acquisition in infants is driven by on-going neural plasticity that is acutely sensitive to environmental acoustic cues. Recent studies showed that attention-based experience with non-linguistic, temporally-modulated auditory stimuli sharpens cortical responses. A previous ERP study from this laboratory showed that interactive auditory experience via behavior-based feedback (AEx), over a 6-week period from 4- to 7-months-of-age, confers a processing advantage, compared to passive auditory exposure (PEx) or maturation alone (Naïve Control, NC). Here, we provide a follow-up investigation of the underlying neural oscillatory patterns in these three groups. In AEx infants, Standard stimuli with invariant frequency (STD) elicited greater Theta-band (4–6 Hz) activity in Right Auditory Cortex (RAC), as compared to NC infants, and Deviant stimuli with rapid frequency change (DEV) elicited larger responses in Left Auditory Cortex (LAC). PEx and NC counterparts showed less-mature bilateral patterns. AEx infants also displayed stronger Gamma (33–37 Hz) activity in the LAC during DEV discrimination, compared to NCs, while NC and PEx groups demonstrated bilateral activity in this band, if at all. This suggests that interactive acoustic experience with non-linguistic stimuli can promote a distinct, robust and precise cortical pattern during rapid auditory processing, perhaps reflecting mechanisms that support fine-tuning of early acoustic mapping

Maturation in auditory event-related potentials explains variation in language ability in children.

Processing of auditory information in the cortex continues to develop into later childhood and adolescence. Recent research has indicated that intraclass correlation (ICC) is the best method for capturing maturation in auditory event-related potentials (AEPs) of school-age children. However, the sensitivity of the ICC approach in discerning AEP changes in children has not been consistently demonstrated and positive results have not been replicated. We attempted this replication and further explored whether AEP maturation estimated using the ICC approach predicts cognitive and linguistic abilities in addition to chronological age. We measured AEPs in response to simple tones in groups of 7-, 8-, 9- and 10-year olds with typical development (N = 67) and used ICC to estimate the age equivalent of each child\u27s AEP (AEP-age). Results indicated that ICC differentiated 7- to 8-year-old children from 9- to 10-year-old children and that AEP-age predicted both chronological age and significant, unique variance in language ability, but not in nonverbal IQ. Our findings support the view that auditory organization in children reflects both general developmental maturation and more specific development of language skills, and support the future use of AEP-age to identify and understand individual differences in brain maturation in typically developing and clinical populations

Developmental trends in auditory processing can provide early predictions of language acquisition in young infants

Auditory processing capabilities at the subcortical level have been hypothesized to impact an individual's development of both language and reading abilities. The present study examined whether auditory processing capabilities relate to language development in healthy 9‐month‐old infants. Participants were 71 infants (31 boys and 40 girls) with both Auditory Brainstem Response (ABR) and language assessments. At 6 weeks and/or 9 months of age, the infants underwent ABR testing using both a standard hearing screening protocol with 30 dB clicks and a second protocol using click pairs separated by 8, 16, and 64‐ms intervals presented at 80 dB . We evaluated the effects of interval duration on ABR latency and amplitude elicited by the second click. At 9 months, language development was assessed via parent report on the Chinese Communicative Development Inventory ‐ Putonghua version (CCDI‐P). Wave V latency z ‐scores of the 64‐ms condition at 6 weeks showed strong direct relationships with Wave V latency in the same condition at 9 months. More importantly, shorter Wave V latencies at 9 months showed strong relationships with the CCDI‐P composite consisting of phrases understood, gestures, and words produced. Likewise, infants who had greater decreases in Wave V latencies from 6 weeks to 9 months had higher CCDI‐P composite scores. Females had higher language development scores and shorter Wave V latencies at both ages than males. Interestingly, when the ABR Wave V latencies at both ages were taken into account, the direct effects of gender on language disappeared. In conclusion, these results support the importance of low‐level auditory processing capabilities for early language acquisition in a population of typically developing young infants. Moreover, the auditory brainstem response in this paradigm shows promise as an electrophysiological marker to predict individual differences in language development in young children. Auditory processing capabilities at the subcortical level have been hypothesized to impact an individual's development of both language and reading abilities. The present study examined whether auditory processing capabilities relate to language development in healthy 9‐month‐old infants. Participants were 71 infants (31 boys and 40 girls) with both Auditory Brainstem Response (ABR) and language assessments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96687/1/desc12012.pd

Detecting violations of temporal regularities in waking and sleeping two-month-old infants

Correctly processing rapid sequences of sounds is essential for developmental milestones, such as language acquisition. We investigated the sensitivity of two-month-old infants to violations of a temporal regularity, by recording event-related brain potentials (ERP) in an auditory oddball paradigm from 36 waking and 40 sleeping infants. Standard tones were presented at a regular 300 ms inter-stimulus interval (ISI). One deviant, otherwise identical to the standard, was preceded by a 100 ms ISI. Two other deviants, presented with the standard ISI, differed from the standard in their spectral makeup. We found significant differences between ERP responses elicited by the standard and each of the deviant sounds. The results suggest that the ability to extract both temporal and spectral regularities from a sound sequence is already functional within the first few months of life. The scalp distribution of all three deviant-stimulus responses was influenced by the infants‟ state of alertness

Multi-level evidence of an allelic hierarchy of USH2A variants in hearing, auditory processing and speech/language outcomes.

Language development builds upon a complex network of interacting subservient systems. It therefore follows that variations in, and subclinical disruptions of, these systems may have secondary effects on emergent language. In this paper, we consider the relationship between genetic variants, hearing, auditory processing and language development. We employ whole genome sequencing in a discovery family to target association and gene x environment interaction analyses in two large population cohorts; the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK10K. These investigations indicate that USH2A variants are associated with altered low-frequency sound perception which, in turn, increases the risk of developmental language disorder. We further show that Ush2a heterozygote mice have low-level hearing impairments, persistent higher-order acoustic processing deficits and altered vocalizations. These findings provide new insights into the complexity of genetic mechanisms serving language development and disorders and the relationships between developmental auditory and neural systems

Hemispheric asymmetry of endogenous neural oscillations in young children: implications for hearing speech in noise

Speech signals contain information in hierarchical time scales, ranging from short-duration (e.g., phonemes) to long-duration cues (e.g., syllables, prosody). A theoretical framework to understand how the brain processes this hierarchy suggests that hemispheric lateralization enables specialized tracking of acoustic cues at different time scales, with the left and right hemispheres sampling at short (25 ms; 40 Hz) and long (200 ms; 5 Hz) periods, respectively. In adults, both speech-evoked and endogenous cortical rhythms are asymmetrical: low-frequency rhythms predominate in right auditory cortex, and high-frequency rhythms in left auditory cortex. It is unknown, however, whether endogenous resting state oscillations are similarly lateralized in children. We investigated cortical oscillations in children (3–5 years; N = 65) at rest and tested our hypotheses that this temporal asymmetry is evident early in life and facilitates recognition of speech in noise. We found a systematic pattern of increasing leftward asymmetry for higher frequency oscillations; this pattern was more pronounced in children who better perceived words in noise. The observed connection between left-biased cortical oscillations in phoneme-relevant frequencies and speech-in-noise perception suggests hemispheric specialization of endogenous oscillatory activity may support speech processing in challenging listening environments, and that this infrastructure is present during early childhood

Resposta sorológica para Leishmania braziliensis utilizando técnica ELISA para cães imunizados com duas vacinas comerciais frente à Leishmaniose Visceral.

O presente projeto pretende avaliar a proteção de duas diferentes vacinas comercialmente disponíveis para proteção contra leishmaniose visceral na proteção contra leishmaniose tegumentar americana (LTA) em cães de município endêmico para enfermidade. Para tanto, serão selecionados pela técnica sorológica de ELISA 70 cães soronegativos para LTA (1,0% da população canina) no município de Íuna, Espírito Santo, sendo posteriormente divididos em dois grupos de igual número e vacinados com três doses segundo orientação dos fabricantes (Leishmune®;FORT DODGE Saúde Animal Ltda / Leish-Tec®;Hertape Calier Saúde Animal S.A.). Semestralmente, estes animais serão monitorados clinicamente e sorologicamente para verificar proteção contra desenvolvimento de LTA. Espera-se que ambas vacinas protejam significativamente os cães vacinados frente a infecção para Leishmania (Viannia) braziliensis

Developmental learning impairments in a rodent model of nodular heterotopia

Developmental malformations of neocortex—including microgyria, ectopias, and periventricular nodular heterotopia (PNH)—have been associated with language learning impairments in humans. Studies also show that developmental language impairments are frequently associated with deficits in processing rapid acoustic stimuli, and rodent models have linked cortical developmental disruption (microgyria, ectopia) with rapid auditory processing deficits. We sought to extend this neurodevelopmental model to evaluate the effects of embryonic (E) day 15 exposure to the anti-mitotic teratogen methylazoxymethanol acetate (MAM) on auditory processing and maze learning in rats. Extensive cortical anomalies were confirmed in MAM-treated rats post mortem. These included evidence of laminar disruption, PNH, and hippocampal dysplasia. Juvenile auditory testing (P21–42) revealed comparable silent gap detection performance for MAM-treated and control subjects, indicating normal hearing and basic auditory temporal processing in MAM subjects. Juvenile testing on a more complex two-tone oddball task, however, revealed a significant impairment in MAM-treated as compared to control subjects. Post hoc analysis also revealed a significant effect of PNH severity for MAM subjects, with more severe disruption associated with greater processing impairments. In adulthood (P60–100), only MAM subjects with the most severe PNH condition showed deficits in oddball two-tone processing as compared to controls. However, when presented with a more complex and novel FM sweep detection task, all MAM subjects showed significant processing deficits as compared to controls. Moreover, post hoc analysis revealed a significant effect of PNH severity on FM sweep processing. Water Maze testing results also showed a significant impairment for spatial but not non-spatial learning in MAM rats as compared to controls. Results lend further support to the notions that: (1) generalized cortical developmental disruption (stemming from injury, genetic or teratogenic insults) leads to auditory processing deficits, which in turn have been suggested to play a causal role in language impairment; (2) severity of cortical disruption is related to the severity of processing impairments; (3) juvenile auditory processing deficits appear to ameliorate with maturation, but can still be elicited in adulthood using increasingly complex acoustic stimuli; and (4) malformations induced with MAM are also associated with generalized spatial learning deficits. These cumulative findings contribute to our understanding of the behavioral consequences of cortical developmental pathology, which may in turn elucidate mechanisms contributing to developmental language learning impairment in humans

Developmental inter-relations between early maternal depression, contextual risks, and interpersonal stress, and their effect on later child cognitive functioning

- Background: Maternal depression and contextual risks (e.g. poverty) are known to impact children's cognitive and social functioning. However, few published studies have examined how stress in the social environment (i.e. interpersonal stress) might developmentally inter-relate with maternal depression and contextual risks to negatively affect a child in these domains. This was the purpose of the current study. - Method: Mother-child pairs (n = 6979) from the Avon Longitudinal Study of Parents were the study participants. Mothers reported on depression, contextual risks, and interpersonal stress between pregnancy and 33 months child age. At age 8, the children underwent cognitive assessments and the mothers reported on the children's social cognitive skills. - Results: Maternal depression, contextual risks, and interpersonal stress showed strong continuity and developmental inter-relatedness. Maternal depression and contextual risks directly predicted a range of child outcomes, including executive functions and social cognitive skills. Interpersonal stress worked indirectly via maternal depression and contextual risks to negatively affect child outcomes. - Conclusion: Maternal depression and contextual risks each increased interpersonal stress in the household, which, in turn, contributed to reduced child cognitive and social functioning