by sending
Your afferent neurons send a message to your brain.
by the medulla oblongata
It depends what the message is.
Besides Brain? Yeah, I did. "Don't tell Brain I hid this secret message! Ha ha, Narf!" Then Brain says "I know about your silly secret message, Pinky."
Your eyes send a message to your brain and then your brain sends a message back telling you what your seeing.
The message of fluid sends a message to your brain causing it to flow up to your brain. The brain cells feed on the caffeine.
It is important to know how the body works. Neurons fire from the brain down nerves into the tongue, to relay the message.
Retina
neurotransmitters
When you want to move a muscle, your brain sends a message out to the muscle you want to move, and the muscle sends a message back to your brain that your moving it and where.
Brain
Afferent