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Abstract:
Late childhood to adolescence is the period when higher-order
cognitive abilities such as abstract thought, goal directed
planning, and voluntary inhibition begin to achieve adult levels
concurrently with significant refinement of neural connectivity in
neocortex. Antisaccade tasks, which are known to be subserved by a
distributed cortical network including frontal eye fields (FEF),
supplementary eye fields (SEF), posterior parietal cortex (PPC),
and prefrontal cortex, provide a method for assessing the integrity
of voluntary inhibitory processes across childhood to adulthood. We
measured eye movements during an antisaccade task in 220 8-45 year
old subjects to evaluate age related changes in performance. We
then compared activation during antisaccades versus prosaccades
using fMRI at 3T in 40 subjects aged 8 to 30 years of age.
Behavioral results showed significant decreases in error rate until
approximately 20 years of age. fMRI studies indicated task related
activity in FEF, SEF, PPC, prefrontal cortex, anterior cingulate,
and lateral cerebellum. Children 8-13 years old demonstrated modest
activation, though localized to the same regions as older subjects.
Adolescent subjects (14-17 years of age) showed extensive
activation in comparison to adults especially in posterior regions.
These results suggest incomplete maturational specialization of
brain function subserving voluntary response suppression into late
adolescence. Supported by NARSAD, NS35949, HD35469, MH42969, &
MH45156.
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