Age-related loss of pattern separation capability in female Sprague-Dawley rats.

CANATELLI-MALLAT, MARTINA; GOYA, RODOLFO G.; MOREL, GUSTAVO R.; LEHMANN, MARIANNE; CHIAVELLINI, PRISCILA

Daegu

Congreso; The 10th World Congress of Neuroscience; 2019

Aging is associated with impaired performance in behavioral pattern separation tasks based on object location or features overlapping memories. In order to evaluate the effect of aging on pattern separation capabilities in female Sprague-Dawley rats we submitted three groups: Young (Y: 4-5 mo., n=25), Middle-Aged (MA: 18 mo., n=32) and Old rats (S: 28 mo., n=13).We performed two experiments for separate location and object discrimination. Experiment 1: spontaneous location recognition task (SLR). At the sample phase (10 min), in the black circular medium density fiberboard device (90 cm diameter, 30 cm high) rats were exposed to three identical objects (cans). At the choice phase (5 min) we removed one object and only used two objects then placed one of the two objects in a new position. Experiment 2: spontaneous object recognition task (SOR). At sample (10 min), in the white foam board triangular open field (60 cm long, 70 cm high), two of the three objects (cans/bottles/lanterns) shared one feature (AB and BC). At the choice (5 min), the novel object was made of the two nonshared features of the objects presented in the sample phase (AC), and the familiar object was a copy of the third object (EF). The results were expressed as a time (t) discrimination ratio [(tnovel ? tfamiliar)/ttotal]. In the SLR, memory showed deterioration in both aged groups as compared with Y animals. (Y: 0.39±0.14; MA: -5.48e-3 ± 0.07; S: 0.012 ± 0.12; One-way ANOVA p=0.03). In the SOR, only S rats presented a deterioration in overlapping memory discrimination, however MA rats showed a preserved overlapping memory discrimination as compared with Y rats (Y: 0.23±0,07; MA: 0,08±0,05; S: -0,27± 0,08; One-way ANOVA p