Multimodal imaging of temporal processing in typical and atypical language development

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110858/1/nyas12688.pd

Patterns of altered neural synchrony in the default mode network in autism spectrum disorder revealed with magnetoencephalography (MEG): Relationship to clinical symptomatology

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142922/1/aur1908.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142922/2/aur1908_am.pd

Language and Literacy Development as Revealed Through the Bilingual Brain

Reading is a dynamic process that varies as a function of environmental and cognitive factors. This dissertation study asked, how does bilingualism influence literacy acquisition, within and across children’s two languages, and through brain development? To answer these questions, the dissertation focuses on theoretical frameworks that suggests early-life bilingual experiences influence the concomitant neural architecture underlying language and cognition. Through two separate studies, I explore the relationship between bilingual children’s dual-language experiences, neural organization for spoken language comprehension, and literacy development in 132 Spanish-English bilingual children ages 7-12. The design and method of the dissertation includes functional Near-Infrared Spectroscopy (fNIRS) neuroimaging during two language comprehension tasks, as well as, behavioral language and cognitive assessments in both languages. In the first study, I found that bilingual children’s language and literacy skills fall within a continuum of shared and unique abilities across languages, and that reading in one language supports reading in another, at the word- and passage- level. In the second study, I found that bilinguals who are equally proficient in both languages show more neural responses to tasks of language comprehension, and this makes a contribution to children’s literacy skills. Findings show how variations in child experiences influences neural organization for language and literacy. This interdisciplinary approach has the potential to yield exciting insights into the brain and behavior of the developing child and carries theoretical implications for understanding acquisition in typical development and in language disorders, across different populations of learners.PHDPsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/151407/1/neewag_1.pd

Contributions of bilingual home environment and language proficiency on children’s Spanish–English reading outcomes

This study examines the influence of language environment on language and reading skills and the cross-linguistic contributions to reading outcomes in 132 Spanish–English bilingual children ages 7–12 (52% female; 98% Hispanic). We present three major findings: children’s language knowledge is separable into general (e.g., phonological awareness) and language-specific (e.g., meaning, grammar) skills; regular Spanish use positively relates to children’s Spanish language and reading skills and does not limit English skills; and Spanish reading comprehension is positively associated with English reading comprehension. The model explains a significant percentage of the variance in English (R2 = .89) and Spanish (R2 = .87) reading comprehension outcomes. Findings shed light on the interdependence of Spanish and English as they relate to bilingual reading acquisition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/173057/1/cdev13748_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/173057/2/cdev13748.pd

Magnetoencephalography shows atypical sensitivity to linguistic sound sequences in autism spectrum disorder

Neuroscientific evidence points toward atypical auditory processing in individuals with autism spectrum disorders (ASD), and yet, the consequences of this for receptive language remain unclear. Using magnetoencephalography and a passive listening task, we test for cascading effects on speech sound processing. Children with ASD and age-matched control participants (8-12 years old) listened to nonce linguistic stimuli that either did or did not conform to the phonological rules that govern consonant sequences in English (e.g. legal \u27vimp\u27 vs. illegal \u27vimk\u27). Beamformer source analysis was used to isolate evoked responses (0.1-30 Hz) to these stimuli in the left and the right auditory cortex. Right auditory responses from participants with ASD, but not control participants, showed an attenuated response to illegal sequences relative to legal sequences that emerged around 330 ms after the onset of the critical phoneme. These results suggest that phonological processing is impacted in ASD, perhaps because of cascading effects from disrupted initial acoustic processing

Multimodal imaging of temporal processing in typical and atypical language development

New approaches to understanding language and reading acquisition propose that the human brain\u27s ability to synchronize its neural firing rate to syllable-length linguistic units may be important to children\u27s ability to acquire human language. Yet, little evidence from brain imaging studies has been available to support this proposal. Here, we summarize three recent brain imaging (functional near-infrared spectroscopy (fNIRS), functional magnetic resonance imaging (fMRI), and magnetoencephalography (MEG)) studies from our laboratories with young English-speaking children (aged 6-12 years). In the first study (fNIRS), we used an auditory beat perception task to show that, in children, the left superior temporal gyrus (STG) responds preferentially to rhythmic beats at 1.5 Hz. In the second study (fMRI), we found correlations between children\u27s amplitude rise-time sensitivity, phonological awareness, and brain activation in the left STG. In the third study (MEG), typically developing children outperformed children with autism spectrum disorder in extracting words from rhythmically rich foreign speech and displayed different brain activation during the learning phase. The overall findings suggest that the efficiency with which left temporal regions process slow temporal (rhythmic) information may be important for gains in language and reading proficiency. These findings carry implications for better understanding of the brain\u27s mechanisms that support language and reading acquisition during both typical and atypical development

Predictive processing during a naturalistic statistical learning task in ASD

© 2020 Wagley et al. Children’s sensitivity to regularities within the linguistic stream, such as the likelihood that syllables co-occur, is foundational to speech segmentation and language acquisition. Yet, little is known about the neurocognitive mechanisms underlying speech segmentation in typical development and in neurodevelopmental disorders that impact language acquisition such as autism spectrum disorder (ASD). Here, we investigate the neural signals of statistical learning in 15 human participants (children ages 8–12) with a clinical diagnosis of ASD and 14 age-matched and gender-matched typically developing peers. We tracked the evoked neural responses to syllable sequences in a naturalistic statistical learning corpus using magnetoencephalography (MEG) in the left primary auditory cortex, posterior superior temporal gyrus (pSTG), and inferior frontal gyrus (IFG), across three repetitions of the passage. In typically developing children, we observed a neural index of learning in all three regions of interest (ROIs), measured by the change in evoked response amplitude as a function of syllable surprisal across passage repetitions. As surprisal increased, the amplitude of the neural response increased; this sensitivity emerged after repeated exposure to the corpus. Children with ASD did not show this pattern of learning in all three regions. We discuss two possible hypotheses related to children’s sensitivity to bottom-up sensory deficits and difficulty with top-down incremental processing

Patterns of altered neural synchrony in the default mode network in autism spectrum disorder revealed with magnetoencephalography (MEG): Relationship to clinical symptomatology

Disrupted neural synchrony may be a primary electrophysiological abnormality in autism spectrum disorders (ASD), altering communication between discrete brain regions and contributing to abnormalities in patterns of connectivity within identified neural networks. Studies exploring brain dynamics to comprehensively characterize and link connectivity to large-scale cortical networks and clinical symptoms are lagging considerably. Patterns of neural coherence within the Default Mode Network (DMN) and Salience Network (SN) during resting state were investigated in 12 children with ASD (MAge  = 9.2) and 13 age and gender-matched neurotypicals (NT) (MAge  = 9.3) with magnetoencephalography. Coherence between 231 brain region pairs within four frequency bands (theta (4-7 Hz), alpha, (8-12 Hz), beta (13-30 Hz), and gamma (30-80 Hz)) was calculated. Relationships between neural coherence and social functioning were examined. ASD was characterized by lower synchronization across all frequencies, reaching clinical significance in the gamma band. Lower gamma synchrony between fronto-temporo-parietal regions was observed, partially consistent with diminished default mode network (DMN) connectivity. Lower gamma coherence in ASD was evident in cross-hemispheric connections between: angular with inferior/middle frontal; middle temporal with middle/inferior frontal; and within right-hemispheric connections between angular, middle temporal, and inferior/middle frontal cortices. Lower gamma coherence between left angular and left superior frontal, right inferior/middle frontal, and right precuneus and between right angular and inferior/middle frontal cortices was related to lower social/social-communication functioning. Results suggest a pattern of lower gamma band coherence in a subset of regions within the DMN in ASD (angular and middle temporal cortical areas) related to lower social/social-communicative functioning. Autism Res 2018, 11: 434-449. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Communication between different areas of the brain was observed in children with ASD and neurotypical children while awake, but not working on a task. Magnetoencephalography was used to measure tiny magnetic fields naturally generated via brain activity. The brains of children with ASD showed less communication between areas that are important for social information processing compared to the brains of neurotypical children. The amount of communication between these areas was associated with social and social communication difficulties