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:Binding of EphB2 to its physiological ligand ephrin initiates signaling pathways critical for neuroplastic processes such as axon guidance, angiogenesis, and long-term potentiation, a form of associative synaptic plasticity observed at hippocampal synapses (Klein, 2008).
Category: