What type of information do the inferior colliculi relay?

• A. Visual information via the lateral geniculate in the thalamus
• B. Auditory information via the medial geniculate in the thalamus
• C. Olfactory information via the olfactory bulb
• D. Somatosensory information via the ventral posterior nucleus

Answer: (B)

The inferior colliculi are the auditory midbrain relay in the central auditory pathway. They take auditory information from lower brainstem nuclei, integrate aspects of sound such as timing and localization, and then send this information upward to the thalamus through the medial geniculate nucleus. From the medial geniculate nucleus, the signal continues to the primary auditory cortex for conscious processing of sound. That’s why the correct description focuses on auditory information carried through the medial geniculate nucleus. Other sensory systems use different thalamic nuclei (visual information goes to the lateral geniculate nucleus; somatosensory information goes to the ventral posterior nucleus), and olfactory processing involves pathways that aren’t described by the inferior colliculus.