corpora quadrigemina

noun plural

cor·​po·​ra quad·​ri·​gem·​i·​na ˌkȯr-p(ə-)rə-ˌkwäd-rə-ˈjem-ə-nə 

: two pairs of colliculi on the dorsal surface of the midbrain composed of white matter externally and gray matter within, the superior pair containing correlation centers for optic reflexes and the inferior pair containing correlation centers for auditory reflexes