title: Age-related changes in tissue signal properties within cortical areas important for word understanding in 12- to 19-month-old infants.
abstract: Recently, our laboratory has shown that the neural mechanisms for encoding lexico-semantic information in adults operate functionally by 12-18 months of age within left frontotemporal cortices (Travis et al., 2011. Spatiotemporal neural dynamics of word understanding in 12- to 18-month-old-infants. Cereb Cortex. 8:1832-1839). However, there is minimal knowledge of the structural changes that occur within these and other cortical regions important for language development. To identify regional structural changes taking place during this important period in infant development, we examined age-related changes in tissue signal properties of gray matter (GM) and white matter (WM) intensity and contrast. T1-weighted surface-based measures were acquired from 12- to 19-month-old infants and analyzed using a general linear model. Significant age effects were observed for GM and WM intensity and contrast within bilateral inferior lateral and anterovental temporal regions, dorsomedial frontal, and superior parietal cortices. Region of interest (ROI) analyses revealed that GM and WM intensity and contrast significantly increased with age within the same left lateral temporal regions shown to generate lexico-semantic activity in infants and adults. These findings suggest that neurophysiological processes supporting linguistic and cognitive behaviors may develop before cellular and structural maturation is complete within associative cortices. These results have important implications for understanding the neurobiological mechanisms relating structural to functional brain development.
authors: Department of Radiology, Multimodal Imaging Laboratory.
authors: Katherine E
authors: KE
authors: Travis
authors: Department of Radiology, Multimodal Imaging Laboratory.
authors: Megan M
authors: MM
authors: Curran
authors: Department of Radiology, Multimodal Imaging Laboratory.
authors: Christina
authors: C
authors: Torres
authors: Department of Radiology, Multimodal Imaging Laboratory.
authors: Matthew K
authors: MK
authors: Leonard
authors: Multimodal Imaging Laboratory, Department of Neurosciences.
authors: Timothy T
authors: TT
authors: Brown
authors: Department of Radiology, Multimodal Imaging Laboratory, Department of Neurosciences.
authors: Anders M
authors: AM
authors: Dale
authors: Kavli Institute for Brain and Mind, and Department of Cognitive Science, University of California, San Diego, CA, USA.
authors: Jeffrey L
authors: JL
authors: Elman
authors: Department of Radiology, Multimodal Imaging Laboratory, Kavli Institute for Brain and Mind, and.
authors: Eric
authors: E
authors: Halgren
mesh_terms: D000375:Aging; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D032882:Comprehension / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007804:Language Development; D008279:Magnetic Resonance Imaging; D008297:Male; D014825:Vocabulary
keywords: brain development; infants; language, structural MRI