The Neuron Doctrine is a fundamental principle in neuroscience that states that the nervous system is made up of individual cells called neurons. Each neuron is a distinct unit that transmits information through electrical and chemical signals. This concept was established in the late 19th century, primarily through the work of scientists like Santiago Ramón y Cajal, who used advanced microscopy techniques to visualize neurons. According to the Neuron Doctrine, neurons communicate with each other at specialized junctions known as synapses. This communication is essential for all brain functions, including thought, movement, and sensation. The doctrine emphasizes that while neurons are interconnected, they remain separate entities, which is crucial for understanding how the brain processes information.