2-Minute Neuroscience: Amyotrophic Lateral Sclerosis (ALS) Video Lecture | A-Z Guide to Neuroscience - Personal Learning

Welcome to 2 minute neuroscience, where I
simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss amyotrophic
lateral sclerosis, or ALS.
Also known as Lou Gehrig’s disease in the
US and motor neuron disease in the UK, ALS
is characterized both by muscle spasticity
and a progressive weakening of the muscles.
As the disease progresses, patients may lose
hand and arm function, and experience difficulty
walking, speaking, and even breathing.
Respiratory failure is often the cause of
death, and the average survival time from
diagnosis is around 3-5 years.
Although some cases of ALS are inherited,
in the vast majority of cases the cause of
ALS is unknown.
ALS is a neurodegenerative disorder, meaning
it is characterized by the degeneration and
death of neurons.
Specifically, the affected neurons in ALS
are called upper and lower motor neurons.
Upper motor neurons extend from the cerebral
cortex or brainstem and carry motor information
down to the spinal cord.
Lower motor neurons extend from the spinal
cord or brainstem to skeletal muscle to cause
movement.
Degeneration of upper motor neurons often
is responsible for spasticity and modest weakness,
but degeneration of lower motor neurons causes
more disabling weakness.
As the motor neurons stop working, muscles
also begin to atrophy.
Mutations in several genes have been linked
to the development of ALS, but the effects
of the mutations are not completely clear
and the mechanism that causes neurodegeneration
in ALS is still not understood.
Similar to other neurodegenerative diseases
like Alzheimer’s disease, ALS is characterized
by the accumulation of dysfunctional proteins
within neurons.
Although the impact of these protein groups
or aggregates is unclear, it is hypothesized
that they could impair neuronal function.
There also are a number of other mechanisms
proposed to play a role in neurodegeneration
in ALS and it is likely more than one is involved.