To understand ALS, one needs to understand how the motor neurons in the brain are divided. The brain has different types of neurons, sensory (for example, detecting touch), and motor neurons (responsible for causing muscle contractions). The motor neurons are the one’s effected by ALS, there are two regions that we will be focusing on, the upper and lower motor neurons.
The upper motor neurons are in the brain and they extend into the lower motor neurons. The lower motor neurons are in the spinal cord going directly to the muscle tissue.
In ALS the body loses control of its motor neuron causing the first symptoms of muscle weakness which progresses to complete loss of all muscle use leading to death. With ALS, the patients typically see lose of arm and leg control first and that is thought to be due to the amount of glutamate released in those neurons. Glutamate is an excitatory neurotransmitter that is released by the neurons.
It is believed from previous research that ALS targets neurons high in glutamate such as the bigger muscle of the arms and legs. The disease keeps progressing in 2 to 3 years causing muscle loss through out the body until the patient passes away.
This all sounds too gloomy, there is good news. In ALS patients, doctors noticed that the eye muscles are usually not affected as much as any other muscles even towards the end of the disease. Recent research shows that the eye muscle neurons have higher levels of a certain Gaba receptor possibly allowing them to fight ALS. The future could still be hopeful for a cure to such an aggressive disease.
How Does ALS Progress?
