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:…Schwann cells (tSCs) at the NMJ mediate the compensatory process: they become activated in response to paralysis or denervation (Reynolds and Woolf, 1992) and extend fine processes, the hallmark of tSC activation, that induce and guide terminal sprouts (Son and Thompson, 1995a; Ko and Chen, 1996).
Category: