Nobuo Suga has recently explored the functional role of the corticofugal system in hearing because the corticofugal system has been poorly studied over the last 40 years and because his lab has found that it is involved in the adjustment and improvement of auditory signal processing.
The auditory system consists of the ascending and descending (corticofugal) systems. Suga has been testing his hypothesis that the corticofugal system reorganizes the central auditory system for a sound that is frequently perceived by an animal, that the reorganization is augmented as the sound becomes behaviorally relevant to the animal through associative learning, and that not only the auditory cortex, but also non-auditory sensory cortices, the amygdala, and the cholinergic basal forebrain are involved in this augmentation.