Environmental enrichment eliminates the anxiety phenotypes in a triple transgenic mouse model of Alzheimer's disease.
Although the impacts of environmental enrichment (EE) in several genetic models of Alzheimer's disease (AD) have been documented, the focus has remained predominantly on cognition. Few have investigated the expression of emotional phenotypes that mimic the notable affective features in AD. Here, we studied the interaction between EE and the coexpression of three genetic risk factors (mutations) for AD. In a longitudinal design, 3×Tg-AD mutants and wild type controls were compared at 6-7 months and subsequently at 12-13 months of age. Under standard housing, phenotypes of heightened anxiety levels were identified in the 3×Tg-AD mice in the elevated plus maze and open-field tests. Such trait differences between genotypes were substantially diminished under EE housing, which was attributable to the anxiolytic impact of EE on the mutant mice as much as the anxiogenic impact of EE on the wild type mice. In contrast, the phenotypes in learned fear were not significantly modified by EE in the tests of Pavlovian freezing and conditioned active avoidance conducted at either age. Rearing under EE thus has uncovered a novel distinction between innate and acquired expressions of fear response in the 3×Tg-AD mouse model that might be relevant to the mental health management of AD.
Laboratory of Behavioural Neurobiology, Swiss Federal Institute of Technology Zurich, Schorenstrasse 16, 8603, Schwerzenbach, Switzerland, susanna.pietropaolo@u-bordeaux1.fr.
Susanna
S
Pietropaolo
Joram
J
Feldon
Benjamin K
BK
Yee
D000367:Age Factors; D000544:Alzheimer Disease / Q000150:complications* / Q000235:genetics; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000818:Animals; D001008:Anxiety Disorders / Q000209:etiology* / Q000235:genetics / Q000451:nursing*; D003214:Conditioning, Classical / Q000502:physiology; D004195:Disease Models, Animal; D004777:Environment; D004924:Escape Reaction / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D046352:Freezing Reaction, Cataleptic / Q000502:physiology; D006801:Humans; D018782:Maze Learning / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D053764:Presenilin-1 / Q000235:genetics; D016875:tau Proteins / Q000235:genetics
D016564:Amyloid beta-Protein Precursor; C508853:PSEN1 protein, human; D053764:Presenilin-1; D016875:tau Proteins