Dihydroergotamine is used to treat migraine headaches and cluster headaches. It is not recommended for migraines that affect only one side of the brain (hemiplegic migraine) or the base of the brain /neck area (basilar migraine), or to prevent migraines from occurring.
Pop music is an abbreviation for popular music. In other words, the main difference between pop music and alternative or underground music is the kind of following it has: pop music is usually known by a lot of people and regularly appears on TV.
Not an easy question, as the delimitation of music genres can be very tricky ! Especially pop, which can also be understood as the adjective popular according to the context. - it comes from rock'n roll, which at first was basically blues with a faster tempo. - it is a hybrid type of music.