The spinoreticular and spinomesencephalic tracts have a similar beginning as the spinothalamic tract. The principal difference is the target structure of the second-order axons. Rather than project to the thalamus as the spinothalamic tract does, the spinoreticular tract projects to the reticular formation in the brainstem to convey the emotional and arousal aspects of pain (eFig. 9.52), and the spinomesencephalic tract projects to the periaqueductal gray matter and superior colliculi in the midbrain for the central modulation of pain (eFig. 9.52).