Microglia are specialized cells in the brain and spinal cord that act as the immune system's first line of defense. They constantly monitor the environment for signs of injury or infection. When they detect a problem, microglia can quickly respond by removing damaged cells and debris, helping to maintain a healthy brain. In addition to their protective role, microglia also play a part in brain development and function. They help shape neural connections and support communication between neurons. By doing so, microglia contribute to learning and memory, making them essential for overall brain health.