The anterolateral pathway forms a reasonably compact bundle of fibers that ascend through the lateral part of the midbrain. Fibers of the spinoreticular division "peel off" at this level and terminate on cells of the reticular formation. Others, termed spinotectal fibers, pass more dorsally to end within the superior colliculus. Cells of the reticular formation, in turn, give rise to axons which ascend to the thalamus within the central tegmental tract (marked here by cross-hatching). While the spinothalamic division may retain some somatotopic organization, it is not precise enough to