Behavioral auditory function after transection of crossed olivo-cochlear bundle in the cat. V. Pure-tone intensity discrimination.

This report describes the cat's ability to discriminate pure-tone intensity differences after transection of the crossed olivo-cochlear bundle at the floor of the fourth ventricle. Cats were trained by behavioral (avoidance) conditioning to detect intensity difference above 75 dB re 0.0002 dyne/cm2 of 10 000 Hz tones, using the repetitive method. Postoperative comparison of data from 5 experimental animals and 5 sham-operated control animals showed minimal differences which reflects merely functional biological variance. Neurohistological examination confirmed the accuracy of the lesion placement.