What is "when you reach up to scratch your nose?

When you reach up to scratch your nose, several things happen involving your nervous system, muscles, and brain:

• Decision & Planning: Your brain decides you want to scratch your nose, likely because of an itch sensation. This involves the sensory cortex (processing the itch) and the motor cortex (planning the movement).

• Motor Commands: The motor cortex sends signals down your spinal cord to the nerves that control the muscles in your arm, shoulder, and hand.

• Muscle Activation: These nerves stimulate the appropriate muscles to contract in a coordinated sequence. This includes muscles for shoulder abduction (raising the arm), elbow flexion (bending the arm), and wrist and finger movements to position your hand near your nose.

• Proprioception: Throughout the movement, your brain receives constant feedback from proprioceptors (sensors in your muscles and joints) about the position of your arm and hand. This allows you to adjust your movements to accurately reach your nose.

• Tactile Feedback: Once your fingers touch your nose, you receive tactile feedback from your skin. This confirms you've reached the target area and allows you to begin the scratching motion.

• Itch Relief: The scratching action disrupts the signals causing the itch sensation, providing temporary relief. This also involves sensory nerves and pathways in your skin.