Final answer:
Neurons in the medulla oblongata control motor reflexes; the target of an upper motor neuron is a lower motor neuron, and the primary motor cortex in the frontal lobe is responsible for initiating voluntary movement.
Step-by-step explanation:
Neurons in the medulla oblongata control motor reflexes. The medulla oblongata, part of the brain stem, is crucial for controlling various autonomic functions such as heart rate and breathing. When considering the target of an upper motor neuron, the correct answer is lower motor neuron. The upper motor neurons originate in the motor region of the cerebral cortex and their axons connect to the lower motor neurons, which ultimately control muscle movements.
The frontal lobe, specifically the primary motor cortex, is responsible for initiating voluntary movement by connecting to cranial and spinal motor neurons. In contrast, the cerebellum is tasked with maintaining balance and aiding in the coordination of movement and motor learning. Importantly, while the cerebellum contributes to coordination during movement, it is not the primary site that controls motor reflexes.