The stretch reflex tests that you demonstrated in this lab require input from the brain in order to work properly.

The stretch reflex is a spinal reflex that does not require input from the brain. It is a rapid and automatic response to stretching of a muscle that helps to maintain muscle tone and posture. The signal travels directly from the sensory receptors in the muscle spindle to the spinal cord, where it activates motor neurons that cause the muscle to contract. While the brain may modulate the stretch reflex, it is not required for it to occur.