Does the lou gehrig's disease happen in or from the brain stem?

Sometimes: In lou gehrig's disease the motor neurons ( the nerves that supply the muscles) die. Your brain is connected to your muscles by 2 nerves, an "upper motor neuron" that lives in the cerebral cortex, that sends a message to a lower motor neuron that lives in the brain stem or spinal cord which in turn connects to the muscle. Either nerve cell can die in als. So the brain stem can be affected.

Rare presentation: Only about 1-2% of all cases of ALS start in the brainstem, progressive bulbar palsy, as most cases are more diffuse, with a mix of upper and lower motor neuron involvement.