RECOVERY OF AVERSIVE THRESHOLDS FOLLOWING MIDBRAIN LESIONS IN CAT

Destruction of ascending pathways in the rostral midbrain of the cat produces striking elevations in aversive or pain thresholds. Similar procedures in humans (mesencephalic tractotomy) lead to a pain relief that is often temporary. To replicate empirically the return of pain found in the neurosurgical clinic, long-term effects of lateral tegmental (LT) lesions in 8 cats were analyzed. Aversive thresholds were measured before and after lesions by an adjusting escape schedule (titration). While thresholds were elevated after LT lesions, all Ss eventually demonstrated some return of sensitivity. The recovery a sensory phenomenon rather than a motor or learning effect. (15 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.