Neuroimaging studies of normative human brain development indicate that the brain
matures at differing rates across time and brain regions, with some areas maturing into
young adulthood. High-resolution structural magnetic resonance imaging (sMRI) allows
for a detailed morphometric analysis of these changes. In particular, changes in cortical
thickness may index maturational progressions from an overabundance of neuropil
toward efficiently pruned neural networks. Changes in sMRI measures have rarely been
examined in relation to neuropsychological functions. In this study, healthy right-handed
adolescents completed sMRI scanning and the Controlled Oral Word Association Test
(COWAT). Age-related associations of task performance and cortical thickness were
assessed with cortical-surface-based analyses. Significant correlations between increasing
COWAT performances and decreasing cortical thickness were found in left hemisphere
language regions, including Wernicke’s and Broca’s areas. Task performance was also
correlated with regions associated with intellectual capacity, effortful verbal and working
memory processing, as well as performance monitoring. Structure-function associations
were not significantly different between older and younger subjects. However, a main
effect of sex was significant in left rostral middle frontal gyrus, with the effect driven
primarily by younger males. Decreases in cortical thicknesses in regions that comprise
the language network likely reflect maturation toward adult-like cortical organization and
processing efficiency. The changes in brain structure that support verbal fluency appear
to be reached in the early teens but with separate developmental trajectories for males and
females, consistent with other studies of adolescent development.
University of Minnesota Master of Arts thesis. November 2009. Major: Psychology. Advisor: Monica M. Luciana, Ph.D. 1 computer file (PDF); v, 41 pages.
Porter, James Norby.
Cortical Maturation and Verbal Fluency in Childhood, Adolescence, and Young Adulthood.
Retrieved from the University of Minnesota Digital Conservancy,
Content distributed via the University of Minnesota's Digital Conservancy may be subject to additional license and use restrictions applied by the depositor.