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:Ultimately, compensatory mechanisms secondary to altered cholinergic signaling might lead to reduced mGluR levels and consequently alters synaptic learning rules and attention behavior (Counotte et al., 2011a, b; Goriounova and Mansvelder, 2012b).
Category: