Final answer:
The tectum of the midbrain is the 'roof' region above the cerebral aqueduct containing the inferior and superior colliculi, which are involved in auditory and multisensory processing, respectively.
Step-by-step explanation:
The tectum is the region of the midbrain that is considered the 'roof' of the cerebral aqueduct. This area of the brain is subdivided into the inferior and superior colliculi. The superior colliculus is a crucial part of the tectum, responsible for aligning visual, auditory, and somatosensory spatial perceptions. The inferior colliculus, part of the auditory pathway in the brain, is involved in the auditory processing and relaying auditory signals to the thalamus and then to the cerebral cortex. Both colliculi play essential roles in sensory processing and reflexive reactions to stimuli.