Fig. 17.

a Schematic representation of the ascending and descending r4-derived tracts. Ascending r4-derived tracts include the lateral lemniscus with multiple midbrain and diencephalic terminals (black), the medial tegmental tract entering the medial forebrain bundle (red), the superficial ascending tract (blue), the trigeminothalamic tract (violet) and the trigeminal and vestibular cerebellopetal tracts (light green and dark green, respectively). Descending r4-derived tracts include the medial spinopetal tract (including medial reticulospinal and medial vestibulospinal fibres) (red), the lateral trigeminal oro-spinal tract (pink) and the lateral vestibulospinal tract (black). b Ramon y Cajal’s 1911 remarkable drawing of the distribution of the lateral lemniscus with terminals reaching inferior colliculus, superior colliculus and thalamus, in agreement with the present results. c A YFP-immunoreacted sagittal section from our material (E18.5; b1r4-Cre/YFP brain), illustrating a similar view of the lateral lemniscus