which carry pain signals修饰哪个？

Of note, while the gray rami communicants contain only postganglionic sympathetic efferent nerves, the white rami communicants contain both efferent preganglionic sympathetic efferent nerves and afferent visceral nerves, which carry pain signals. The anatomic contents of the white rami communicants describe the only neural traffic between the central nervous system and sympathetic nervous system [2, 9].

值得注意的是，灰色交通支只包含节后交感传出神经，而携带疼痛信号的白色交通支既包含节前交感神经传出神经，也包含内脏传入神经。白交通支的解剖学意义在于是中枢神经系统和交感神经系统间唯一的神经联系^[2,9]。