Cortical and midbrain mediation of a conditioned discrimination of acoustic intensities.

Conditioned auditory responses established in decorticate dogs and cats must be mediated subcortically. Complete simultaneous bilateral removal of the auditory cortex does not interfere with initial learning of a conditioned response and does not prevent relearning of a pre-operatively acquired habit. This would imply a neural connection between subcortical auditory centers and motor mechanisms. Kryter and Ades1 have suggested that the quadrigeminal nuclei may serve this function.