Ageing and plasticity: immediate and long term effects of enriched environment on spatial memory on aged rats

• Grant number: 13/16427-3
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2014
• End date: January 31, 2016
• Field of knowledge: Humanities - Psychology - Experimental Psychology
• Principal Investigator: Edvaldo Soares
• Grantee: Edvaldo Soares
• Host Institution: Faculdade de Filosofia e Ciências (FFC). Universidade Estadual Paulista (UNESP). Campus de Marília. Marília , SP, Brazil
• Associated researchers: Paulo Sergio Teixeira do Prado ; Sebastião Marcos Ribeiro de Carvalho ; Vitor Engrácia Valenti

Abstract

The study aims verify the immediate, long term and after the ageing effects of environmental conditions on spatial memory. Will be used 30 male albino Wistar rats, being distributed randomly in 3 same-sized groups: Experimental 1 (GEP1), Experimental 2 (GEP2) and Control (GCT). The experiment will begin after the ablactation, when the animals complete 40 days of life. The subjects on GEP1 will be submitted, after 7 day ambiance on enriched environment (EE) during 30 consecutive days, after the 50th day of life. The GEP2 and GCT will be kept in standard propylene boxes, in groups of four rats per box. All the subjects will be deprived of food 12 hours per day before the experimental sessions. For the EE, will be used two open fields, where will be put several objects, made by the researchers and factory made ones. During the first 10 sessions on EE, the two fields will be isolated and from 11th session onward, they will be interconnected. Some objects, called "toys" by the researchers produces sounds when moved, others will be constituted as challenges for obtainment of food as climb a platform, go through a "tunnel", touch a suspended object, etc. In each field, initially, will be placed 5 animals. The fields will be modified periodically. The experimental group animals (GEP1 and GEP2) will be taken to the EE approximately at 18h30, respecting its circadian cycle. The experimental subjects will stay in the EE two hours per day, five days per week. At the end of a 30 day period, being the animals 90 days old, the subjects of GEP1 and GCT will be submitted to the Morris' Aquatic Labyrinth (LAM). From there on, all the subjects will be kept in couples on the polypropylene boxes with free access to water and food, however without EE stimulation. Upon completion of 370 days of life, the animals on GEP1 and GCT will be again evaluated on LAM. The tests will be filmed and analysed by a field monitoring system(Insight's Software Monitor de Campo). After this test, they will return to their polypropylene boxes, in couples, with free access to water and food and without EE stimulation, until they complete 460 days of life, corresponding to the beginning of the ageing period in humans. From this, the animals on GEP2 will be submitted to EE on the same initial conditions as GEP1, while the subjects on GEP1 and GCT will be kept from stimulation. Upon completing 540 days of life, the animals on GEP1, GEP2 and GCT will be tested again on LAM. After LAM's testing, all animals will be kept in couples on their polypropylene boxes, with free access to water and food, however without any kind of stimulation or extra activities, for a period of 30 days. After 30 days, all subjects from groups GEP1, GEP2, GCT will be subdivided randomically in six subgroups of equal size: a) Subgroup 1: GEP1(1); GEP2(1) and GCT(1) e b) Subgroup 2: GEP1(2); GEP2(2) and GCT(2). The animals on subgroup 1 will be subjected to AE (enriched environment) for 30 days while animals on subgroup 2 will not have AE exposition. After this period, will be again applied the LAM test for all research subjects. (AU)