Brainstem pathways of reward

Tested 134 albino rats implanted with a single bipolar electrode aimed at a brainstem site for self-stimulation. 6 Ss were subjected to small lesions at the stimulation site so that degeneration from reward and neutral regions could be compared. Structures not typically related to reward (substantia nigra, brachium conjunctivum, ventral tegmental decussation, rubrospinal tract) yielded self-stimulation, while brainstem structures typically associated or implicated in the reward process (reticular formation, tegmental reticular nucleus, dorsal tegmental nucleus) did not yield self-stimulation behavior. Degeneration experiments supported the mapping work by implication of the brachium conjunctivum as 1 reward pathway. Results point to the significance of the extrapyramidal system in brainstem reward, and the possibility that the red nucleus may occupy a nodal position in this reward system. (26 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).