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ABSTRACT Language is thought to have multiple sensitive periods in early childhood, but the neural basis of these sensitive periods is less understood. We leverage advances in in‐vivo neuroimaging of plasticity, measuring the neural inhibition across the brain via Hurst exponent. Using two large datasets with children ages 10 months to 18 years (Baby Connectome Project: 10m‐3y6m, 458 observations acrossn= 222 children; Human Connectome Project‐Development: 5–18y,n= 437), we characterize the development of the Hurst exponent in language‐related brain regions. In early childhood, Hurst increases in temporal and frontal language areas, and posterior regions develop earlier than anterior regions. In contrast, thalamic Hurst plateaus earlier, perhaps underlying the earliest language‐related sensitive periods. Children with higher language‐related skills show slower increases in cortical Hurst in early childhood, suggesting protracted plasticity. Later in childhood, cortical Hurst plateaus around age 9, suggesting a potential neural mechanism for age‐related declines syntax learning. These results highlight a potential neural basis for cascading language‐related sensitive periods.
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This content will become publicly available on April 28, 2027
Self‐Affine Scaling of Earth's Islands
Abstract Earth's relief is approximately self‐affine, meaning a zoom‐in on a small region looks statistically similar to a large region upon rescaling. Fractional Brownian surfaces give an idealized self‐affine model of Earth's relief with one parameter, the Hurst exponent , characterizing the roughness of the surface. We compile a large data set of topographic profiles of islands (N = 131,063 with the range of areas covering approximately 8 orders of magnitude) and obtain four estimates for the Hurst exponent of Earth's surface by fitting four statistical laws from the theory of self‐affine surfaces concerning islands: (a) distribution of areas, (b) volume‐area relationship, (c) perimeter‐area relationship, and (d) maximum height‐area relationship. The estimated Hurst exponents indicate different fractal scaling behavior for different geometric features, and are sorted in order of increasing expected influence of coastal processes. This sheds light on the impact of coastal erosion and sedimentation on island geomorphology.
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- Award ID(s):
- 2235451
- PAR ID:
- 10686908
- Publisher / Repository:
- AGU
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 53
- Issue:
- 8
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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