Why pupils are not constricted in central pontine myelinolysis?

In central pontine myelinolysis, the primary issue is the demyelination of axons in the pons, which affects the brain's ability to process and relay signals properly. Pupils remain non-constricted because the condition primarily disrupts the pathways involved in voluntary motor control and does not directly affect the autonomic pathways that control pupil size. The pupils typically respond to light and accommodation through intact midbrain reflexes, which remain functional despite the demyelinating process. Thus, central pontine myelinolysis does not lead to the pupillary constriction often seen in other neurological conditions.