Chronic stress impairs spatial memory and motivation for reward without disrupting motor ability and motivation to explore.
This study uses an operant, behavioral model to assess the daily changes in the decay rate of short-term memory, motivation, and motor ability in rats exposed to chronic restraint. Restraint decreased reward-related motivation by 50% without altering memory decay rate or motor ability. Moreover, chronic restraint impaired hippocampal-dependent spatial memory on the Y maze (4-hr delay) and produced CA3 dendritic retraction without altering hippocampal-independent maze navigation (1-min delay) or locomotion. Thus, mechanisms underlying motivation for food reward differ from those underlying Y maze exploration, and neurobiological substrates of spatial memory, such as the hippocampus, differ from those that underlie short-term memory. Chronic restraint produces functional, neuromorphological, and physiological alterations that parallel symptoms of depression in humans.
Kleen
Jonathan K
JK
Department of Psychology, Arizona State University, Tempe, AZ 85224-1107, USA.
Sitomer
Matthew T
MT
Killeen
Peter R
PR
Conrad
Cheryl D
CD
D000311:Adrenal Glands / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D004435:Eating / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology*; D006624:Hippocampus / Q000473:pathology; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology* / Q000473:pathology; D009042:Motivation; D009043:Motor Activity / Q000502:physiology*; D009929:Organ Size / Q000502:physiology; D010424:Pentobarbital / Q000494:pharmacology; D017966:Pyramidal Cells / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012201:Reward; D013312:Stress, Physiological / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors
D006993:Hypnotics and Sedatives; D010424:Pentobarbital