Final answer:
The cerebellum, also known as the "little brain," is responsible for processing sensory input, coordinating movement, and balance, as well as enabling nonverbal learning and memory. It is a critical component of the brainstem that aids in motor learning and maintaining procedural memory despite other memory impairments.
Step-by-step explanation:
The "little brain" at the rear of the brainstem, which processes sensory input, coordinates movement output and balance, and enables nonverbal learning and memory, is known as the cerebellum. The cerebellum, deriving its name from Latin meaning "little brain," is positioned at the base of the brain atop the brainstem. This brain region is critical for controlling balance, aiding in the coordination of movement, and contributing to the learning of new motor tasks. The brainstem itself, which the cerebellum is attached to, is composed of the midbrain, the medulla oblongata, and the pons. It's involved in several vital functions such as breathing, heart rate, and the integration of sensory and motor information.
It's also important to note that the cerebellum plays a role in the type of memory known as procedural memory, which is involved in learning and remembering how to perform tasks. Despite any impairments in the ability to form new explicit memories, as in the case of a patient like H.M., the intact cerebellum allows for learning new tasks, demonstrating the significance of the cerebellum in our motor learning and memory capabilities.