Deep inside the brain is a small but powerful region called the substantia nigra. Its job is to produce dopamine, a messenger molecule that allows your body to move smoothly and with control. But these dopamine-producing cells are vulnerable. Over time, they can be damaged by inflammation, toxins such as heavy metals, or even certain infections. In some cases, the immune system may mistakenly contribute to this damage. As these cells decline, dopamine levels drop—and the ability to move easily b