general somatic efferent fibers general somatic efferent fibers the general (spinal) somatic efferent neurons (gse, somatomotor, or somatic motor fibers), arise from motor neuron cell bodies in the ventral horns of the gray matter within the spinal cord. they exit the spinal cord through the ventral roots, carrying motor impulses to skeletal muscle through a neuromuscular junction. general somatic efferent fibersscheme showing structure of a typical spinal nerve.1. somatic efferent.2. somatic afferent.3,4,5. sympathetic efferent.6,7. sympathetic afferent.anatomical terminology of the somatic efferent neurons, there exist subtypes. alpha motor neurons (α) target extrafusal muscle fibers. gamma motor neurons (γ) target intrafusal muscle fibres cranial nerves also supply their own somatic efferent neurons to the extraocular muscles and some of the muscles of the tongue.