What is the primary responsibility of the midbrain?

The midbrain, or mesencephalon, plays a crucial role in processing visual and auditory signals. It serves as an important relay center for sensory information, meaning it receives input from visual and auditory pathways and integrates that information to guide behaviors and reflexes. Specific structures within the midbrain, such as the superior and inferior colliculi, are specifically dedicated to the processing of visual and auditory stimuli, respectively. This sensory processing is vital for various functions, such as maintaining coordination and reflexive responses to visual and auditory cues in the environment.

In contrast, the other options refer to functions associated with different parts of the brain: regulating heart rate and blood pressure is primarily the responsibility of the medulla oblongata, emotional responses are primarily processed by the limbic system, and motor control is managed by areas like the cerebellum and basal ganglia. Therefore, the midbrain's main function is accurately described by its role in receiving and processing visual and auditory signals.