Roughness discrimination in cats with dorsal column lesions

Abstract

1. (1) Seven normal cats and 17 cats with dorsal column total (DC) lesions of 2-100% of the DC cross-sectional area were given neurological tests. Cats with lesions as large as 86% showed no deficits on neurological examination. All cats with lesions greater than 90% showed signs of neurological impairment.2. (2) Six cats with high cervical DC lesions were compared with 4 intact controls in a roughness-discrimination task of 4 graded levels. Two cats with 97% and 100% destruction of their total DC cross-sectional area failed to reach criterion on the second discrimination level; cats with 38-86% DC lesions learned the highest discmination grade as quickly as intact controls.3. (3) DC lesions of 69-86% in pretained cats failed to produce evidence of lasting postoperative deficits when compared with pretrained, sham-operated controls; however, a cat with a 100% lesion failed to reach criterion on the second discrimination level.4. (4) The results show that the effects of DC lesions in cats can be demonstr by neurological examination and roughness-discrimination tests. However, to show significant effects, at least 90% of the dorsal columns must be destroyed; in this study, such lesions were estimated to involve over 90% of the DC fibers transmitting information from the paws. Although these findings suggest a high level of functional redundancy within the DC system, alternative views of DC function and its analysis are suggested.