The brain and hearing: auditory discriminations affected by brain lesions.

After bilateral ablation of the auditory areas of the cerebral cortex, experimental animals have a severe deficit in ability to discriminate between temporal patterns of tonal stimuli and to localize sound in space. These two kinds of discrimination are basic for communication and for attack or avoidance of prey and predator. Recognition of which ear is stimulated may also depend upon excitation of auditory cortex contralateral to the given ear. Binaural discriminations are dependent upon interaction of nerve impulses from the two ears at a low level in the auditory nervous system. Similar hearing losses have been reported for human patients.