White matter development in adolescence: diffusion tensor imaging and meta-analytic results.

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Brain Imaging

Background:

• Schizophrenia is associated with white matter (WM) abnormalities.
• Studying normal adolescent WM maturation offers insights into schizophrenia's neurodevelopment.
• Previous diffusion tensor imaging (DTI) studies show increasing fractional anisotropy (FA) with age, but findings vary across WM tracts.

Purpose of the Study:

• To identify WM tracts with the most significant maturation changes during adolescence.
• To confirm findings through a meta-analysis of existing DTI studies.

Main Methods:

• Diffusion tensor imaging (DTI) was performed on 78 healthy individuals aged 8-21 years.
• Voxel-wise analysis was conducted using tract-based spatial statistics (TBSS).
• A meta-analysis of published TBSS studies on adolescent WM development was performed.

Main Results:

• Fractional anisotropy (FA) increased with age bilaterally, most notably in the left superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and anterior thalamic radiation.
• Meta-analysis confirmed these findings, with bilateral SLF FA increase being the most consistent result.
• In the study sample, SLF FA correlated positively with verbal working memory and partially mediated age-related increases in verbal fluency.

Conclusions:

• Adolescence is characterized by increasing connectivity within the SLF.
• Compromised SLF integrity is observed in individuals at high risk for and with first-episode schizophrenia.
• Abnormal SLF maturation during adolescence may be a critical factor in schizophrenia's neurodevelopment.