Explain why Gegenhalten, Mitmachen/Mitgehen, and negativism are best understood as points on a single spectrum rather than as entirely separate, unrelated signs.

All three signs concern how a patient's motor system responds to an examiner's attempt to passively move a limb, differing chiefly in the degree and direction of the response rather than in any fundamentally different underlying mechanism. Mitgehen, at one end, offers no resistance at all, moving readily even with minimal pressure; Gegenhalten sits in the middle, offering resistance that matches the force applied; and negativism, at the other end, is a more marked, apparently motiveless resistance extending beyond passive movement to interference more generally. Understanding them as a spectrum, rather than as isolated signs, helps a clinician recognise milder or borderline presentations and appreciate that a patient's findings may shift along this continuum over the course of an illness.