Midbrain Several BDA labeled axons were observed in theperiaqueductal gray matter (PAG). The moderate BDA labeledterminals were found in the lateral superior colliculus (SC).

• 中脑：中脑导水管周围灰质(PAG)内可观察到少量BDA标记纤维终末的分布，上丘的外侧有中等密度BDA标记纤维和终术，中脑深核有密集的BDA标记纤维终末；