The exact meaning of invoke can depend upon its context. For example:
"invoking God's help"; or "invoking the spirit of the dead" — to call upon a great or magical power
"I invoke the First Amendment"; or "I invoke the words of Thomas Jefferson" — to cite or call upon for validation
"She invoked his sympathy and family memories." — to call upon someone's feelings or memories
"She invoked his assistance." — to call earnestly for
"The program invokes the subroutine" — to call up a computer program
A fat old man and dirty and unvirtuous was the Doc; his grammar was doubtful, his vocabulary alarming, and his references to his rival, good Dr. Needham, were scandalous; yet he invoked in Martin a vision of making chemicals explode with much noise and stink and of seeing animalcules that no boy in Elk Mills had ever beheld.