  Adolescence is marked by rapid development of executive function. Mounting
evidence suggests that executive function in adults may be driven by dynamic
control of neurophysiological processes. Yet, how these dynamics evolve over
adolescence and contribute to cognitive development is unknown. Using a novel
dynamic graph approach in which each moment in time is a node and the
similarity in brain states at two different times is an edge, we identify two
primary brain states reminiscent of intrinsic and task-evoked systems. We
demonstrate that time spent in these two states increases over development, as
does the flexibility with which the brain switches between them. Increasing
time spent in primary states and flexibility among states relates to increased
executive performance over adolescence. Indeed, flexibility is increasingly
advantageous for performance toward early adulthood. These findings demonstrate
that brain state dynamics underlie the development of executive function during
the critical period of adolescence.
