A monosynaptic pathway from dorsal cochlear nucleus to auditory cortex in rat.

Of the three major subdivisions of the auditory thalamus, the medial subdivision is the only one that receives a direct projection from the dorsal cochlear nucleus. Those cells in the medial auditory thalamus that receive the projection from the dorsal cochlear nucleus continue to the auditory cortex. A combination of anterograde and retrograde anatomical tracer injections made in the dorsal cochlear nucleus and the auditory cortex respectively, revealed terminal boutons which were directly apposed onto the dendrites and cell bodies of neurons in the medial auditory thalamus. The presence of a monosynaptic pathway, which transfers information from the first relay in the auditory system to the last, suggests that this pathway may rapidly convey very basic information to the auditory cortex.