The sensitivity of muscle spindles to stretch can be adjusted by?

The sensitivity of muscle spindles to stretch can be adjusted by the gamma motor neurons. Gamma motor neurons innervate the intrafusal muscle fibers of the muscle spindle, which are responsible for generating the stretch reflex. When gamma motor neurons are activated, they cause the intrafusal muscle fibers to contract, which increases the tension on the spindle and makes it more sensitive to stretch. This is known as the gamma-loop mechanism.