self-agency, reward, and anxiety

Our previous work demonstrated that behavioral inhibition is
associated with perturbations in the appetitive-motivational system.
In this study, we found that these perturbations were specific to the
condition in which participants believed that choice of self-executed
responses determined outcomes, and did not extend to the condition in
which outcomes were independent of subjects' agency. Indeed, a sense
of "responsibility," or self-agency, in a context of uncertainty
(probabilistic outcomes) drives the neural system underlying
appetitive motivation (i.e., nucleus accumbens) more strongly in
temperamentally inhibited than noninhibited adolescents. One important
next step will be to determine how the reward system interacts with
fear circuitry among subjects characterized by behavioral inhibition
and elevated anxiety. --
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785902/