[TA] a bundle of thick, heavily myelinated fibers originating in the deep layers of the superior colliculus, crossing to the opposite side in the dorsal tegmental decussation, descending along the median plane, between the medial longitudinal fasciculus dorsally and the medial lemniscus ventrally, and into the anterior funiculus of the spinal cord. The tract ends in the medial region of the anterior horn of the cervical spinal cord, and appears to be involved in head movements during visual and auditory tracking. Throughout its course in the brainstem, it is accompanied by fibers of the tectobulbar tract. SYN: tractus tectospinalis [TA], Held bundle, Loewenthal bundle, Loewenthal tract, Marchi tract, predorsal bundle.