The doctor explains to Stephen Hawking that Motor Neuron Disease is affecting his ability to use any muscle activity, such as speaking, walking, breathing, and swallowing. The signals that tell the muscles to move are disrupted, and the result is gradual muscle decay.
Scientists are studying tadpoles to look at how their neural circuits develop. These neural circuits are made up of many neurons. Neurons generate electrical and chemical signals in order to communicate with one another.
Experts explain what would happen if we did not have any memory and what happens in our brain in order to store information and memories. Memory is an aspect of the brain that makes us fundamentally human and enables us to remember important ideas and lessons to keep us safe.
Jeffrey provides an overview of muscles and explains how they help our bodies move. He then describes how muscles grow in size and mentions that muscles need more than activity to grow: they also need proper nutrition and rest.