||In the adult bilaterally paired compact tract located lateral to the medial forebrain bundle that extends to the diencephalon. Formed from several fascicles that originate in the precommissural telencephalon and converge rostrocaudally. In the seven day old fish bilaterally paired bundle that runs caudally from the anterior commissure to the forebrain. In the caudal diencephalon the bundle divides into two parts. The thinner part runs more laterally and ventrally, and the thicker part was located more medially and dorsally. Both bundles run in the caudal direction toward the cranial wall of the lateral recess of the diencephalic ventricle, where they apparently exchange some fibers. Then, they continue in the caudal direction, surrounding the lateral recess from the ventral and dorsal side, and meet close to the caudal wall of lateral recess at the level of the commissure of the posterior tuberculum.