1. Sensory neurons: These neurons carry signals from sensory receptors in the body, such as the eyes, ears, skin, and muscles, to the central nervous system (CNS). They are responsible for transmitting information about the external and internal environment to the brain and spinal cord.

2. Motor neurons: These neurons carry signals from the CNS to muscles and glands, causing them to contract or secrete substances. They are responsible for initiating and controlling voluntary movements, as well as regulating involuntary functions such as breathing and digestion.

3. Interneurons: These neurons connect other neurons within the CNS. They are responsible for processing information, integrating signals, and making decisions. They are the most numerous type of neuron in the human brain and play a crucial role in learning, memory, and complex cognitive functions.

It's important to note that these three types of neurons are not entirely independent. They work together in complex networks to process information and control bodily functions.