Final answer:
Cerebrovascular lesions in the prefrontal cortex are most likely to cause post-event depressive symptoms.
Step-by-step explanation:
The region in the brain where cerebrovascular lesions are most likely to cause post-event depressive symptoms is the prefrontal cortex. This area of the brain is involved in regulating emotions, motivation, and decision-making. Damage to the prefrontal cortex can disrupt these functions and lead to depressive symptoms. For example, studies have shown that depletion of dopamine in the prefrontal cortex can cause cognitive deficits, which are sometimes observed in depressive disorders.