Medial Geniculate Body
This nucleus (D3) is the diencephalic relaystation of the auditory pathway. It appears asan externally visible eminence medially to the lateral geniculate body. Its afferent fibers form the brachium of the inferior col-liculus from the ipsilateralinferior colliculus(D4). Some fiber bundles of the auditory pathway come from the nucleus of the trape-zoid body and the ipsilateral cochlear nuclei;however, most fibers originate from the contralateral cochlear nuclei. The efferent fibers of the medial geniculate nucleus ex-tend to the auditory cortex (D5), which lies in the transverse temporal gyri, or Heschl’s con-volutions of the temporal lobe.