One of two types of somatic motoneurons that innervate intrafusal muscle fibers found within the muscle spindle. They regulate the sensitivity of the spindle to muscle stretching, thus enabling intrafusal fibers to contract (and shorten). When gamma neurons are activated, intrafusal muscle fibers contract such that only a small stretch is required to activate spindle sensory neurons and the stretch reflex. There are two types of gamma motoneurons: gamma dynamic motor neurons innervating dynamic bag muscle cells and gamma static motor neurons that innervate static bag muscle cells and chain muscle cells.
See Alpha (α) motoneuron, Extrafusal muscle fibers, Intrafusal muscle fibers, Motoneuron, Muscle spindle