Abstract: | Non-mesencephalic origins of ascending afferents to the thalamic auditory nuclei, nuclei ovoidalis (Ov) and semilunaris parovoidalis (SPO), were identified in the pigeon in retrograde tracing experiments. These origins comprise dorsal and ventral lateral lemniscal nuclei. Injections of anterograde tracers into these nuclei produced terminal labelling in SPO in particular. These experiments show for the first time that the inferior colliculus is not an obligatory relay to the auditory thalamus. |