Neurodegenerative diseases are conditions that cause the gradual degeneration or death of nerve cells, known as neurons, in the brain and nervous system. This process can lead to a decline in cognitive functions, movement, and overall health. Common examples include Alzheimer's disease, which affects memory and thinking, and Parkinson's disease, which impacts movement and coordination. These diseases often develop slowly and worsen over time, making daily activities increasingly challenging. While the exact causes are not fully understood, factors like genetics, age, and environmental influences may play a role. Research is ongoing to find better treatments and potential cures for these debilitating conditions.