Biology subjects

Gabard-Durnam, L. J.

Publications and source records attributed to Gabard-Durnam, L. J..

3 recordsLinked to original sources

bioRxiv2018

Reduced frontal gamma power at 24 months is associated with better expressive language in toddlers at risk for autism

Gamma oscillations have been associated with early language development in typically developing toddlers, and gamma band abnormalities have been observed in individuals with ASD, as well high-risk infant siblings (those having an older sibling with autism), as early as 6-months of age. The current study investigated differences in baseline frontal gamma power and its association with language development in toddlers at high versus low familial risk for autism. EEG recordings as well as cognitive and behavioral assessments were acquired at 24-months as part of prospective, longitudinal study of infant siblings of children with and without autism. Diagnosis of autism was determined at 24-36 months, and data was analyzed across three outcome groups - low risk without ASD (n=43), high-risk without ASD (n=42), and high-risk with ASD (n=16). High-risk toddlers without ASD had reduced baseline frontal gamma power (30-50Hz) compared to low-risk toddlers. Among high-risk toddlers increased frontal gamma was only marginally associated with ASD diagnosis (p=0.06), but significantly associated with reduced expressive language ability (p=0.007). No association between gamma power and language was present in the low-risk group. These findings suggest that differences in gamma oscillations in high-risk toddlers may represent compensatory mechanisms associated with improved developmental outcomes.

neuroscience↗

bioRxiv2018

Music reveals medial prefrontal cortex sensitive period in childhood

An outstanding issue in our understanding of human brain development is whether sensitive periods exist for higher-order processes (e.g., emotion regulation) that depend on the prefrontal cortex. Evidence from rodent models suggests that there is a sensitive period before puberty when acoustic stimuli, like music, shape medial prefrontal cortex (mPFC) responses that regulate affect in the context of acute stress in adulthood. The present study examined whether a homologous sensitive period for the mPFC occurs during human childhood. In the context of acute stress, adult behavioral preferences were observed only for music experienced during childhood, not preschool or adolescent periods. Childhood music increased mPFC activation and modulated connectivity with the amygdala, which was associated with enhanced emotion regulation and lowered autonomic arousal. Moreover, the timing of this sensitive period could be moved by early-life stress. These findings indicate that childhood is a sensitive period for mPFC encoding of regulatory stimuli.\n\nSensitive periods are developmental moments of heightened neuroplasticity when experiences shape brain function and behavior with lasting effects (1). They are fundamental to human cortical ontogeny, and yet, the timing and nature of sensitive periods for human prefrontal cortex functions remain unknown (2-8). In the rodent, Yang and colleagues have shown that the medial prefrontal cortex (mPFC) exhibits a sensitive period during the prepubertal juvenile period, with heightened responsivity to complex auditory stimuli (i.e., music) (9). Specifically, initial exposure to music during the open (juvenile) sensitive period or a pharmacologically re-opened sensitive period in adulthood was followed by that music uniquely producing a behavioral preference in adulthood, increasing mPFC activity, and reducing anxiety-like behavior. This finding and others converging on the same prepubertal period of plasticity in the rodent (9, 10) may have important implications for human development; the complementary prepubertal period in humans (i.e., school-age childhood) also exhibits developmentally-unique mPFC circuitry phenotypes (11-17) that make childhood a strong candidate for a human mPFC sensitive period. Here, we used Billboard music chart data to identify age-specific exposures to pop songs to test whether music shapes human mPFC responses during a childhood sensitive period as in the rodent. To parallel the approach used in the rodent, we examined whether (i) music experienced during childhood uniquely produced a behavioral preference under stress, (ii) childhood music enhanced emotion regulation behaviorally and physiologically, (iii) mPFC activity was enhanced by childhood music, and mPFC circuitry mediated emotion regulation benefits of childhood music, and (iv) whether the timing of this putative sensitive period could be shifted by early adversity.

neuroscience↗

bioRxiv2018

Emergence of Human Amygdala Functional Networks: 3 Months to 5 Years of Age

Although the amygdalas role in shaping social behavior is especially important during early post-natal development, very little is known of human amygdala functional development before childhood. To address this important gap, this study used resting-state fMRI to examine early functional network development of the amygdala and its subregions in 80 participants from 3-months to 5-years of age. Whole brain functional connectivity with the whole amygdala and its laterobasal and superficial nuclear groups were largely similar to those seen in older children and adults, and functional distinctions between subregion networks exist already. These patterns suggest many amygdala functional circuits are intact from infancy, especially those that are part of larger motor, visual, auditory and subcortical (basal ganglia especially) networks. Notably, these observed robust amygdala functional networks in infancy precede reports to date of elicited amygdala reactivity in development. Developmental changes in connectivity were observed between the laterobasal nucleus and bilateral ventral temporal and motor cortex as well as between the superficial nuclei and medial thalamus, occipital cortex and a different region of motor cortex. These results show amygdala-subcortical and sensory-cortex connectivity begins refinement prior to childhood, though connectivity changes with associative and frontal cortical areas, seen after early childhood, were not evident in this age range. These findings represent early steps in understanding amygdala network dynamics across infancy through early childhood, an important period of emotional and cognitive development.

neuroscience↗