Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Consistent with these experimental findings in animals, head-down rotation (HDR) performed in young adults, which engages the otolith organs of the vestibular system, increases muscle sympathetic nerve activity (MSNA) and produces limb vasoconstriction (14, 20, 25, 34).
Category: