TY - JOUR T1 - Operantly conditioned plasticity and circadian rhythm in rat H-reflex are independent phenomena. JF - Neuroscience letters Y1 - 1995 A1 - Xiang Yang Chen A1 - Jonathan Wolpaw KW - circadian rhythm KW - H-Reflex KW - Learning KW - Memory KW - operant conditioning KW - Rats AB - Recent studies indicate that rats can increase or decrease H-reflex amplitude in response to an operant conditioning paradigm. In addition, rats also display a circadian rhythm in H-reflex amplitude. As part of the development of H-reflex conditioning in the rat as a new model for defining the plasticity underlying a simple form of learning, this study examined the relationship in the rat between operantly conditioned H-reflex change and the H-reflex circadian rhythm. When H-reflex amplitude increased or decreased in response to the operant conditioning program, its circadian rhythm showed no changes in phase and minimal change in amplitude. Furthermore, animals did not alter daily performance schedule so as to use the rhythm to increase reward probability. Thus, in the rat, H-reflex operant conditioning and the H-reflex circadian rhythm appear to be independent phenomena. The circadian rhythm should not be a significant complicating factor in studies of operantly conditioned H-reflex change. VL - 195 UR - http://www.ncbi.nlm.nih.gov/pubmed/7478262 ER -