Spatial working memory training in aged rats: effects in anxiety, habituation and density of cells in the hippocampus

Author(s)

Aline Vilar Machado Nils

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2015-12-07

Examining board members

Gilberto Fernando Xavier; Miriam Mendonça Morato de Andrade; Fernando Canova; Simone Cristina Motta

• Advisor: Gilberto Fernando Xavier

Abstract

Decline in memory fuctions are related to aging process. Spatial learning and memory deficits are induced by aging in rodents. Elderly also correlates with decreases in exploratory behaviour and increments in baseline anxiety. The development of strategies that focus on the prevention of anxiety disorders and cognitive disabilities are needed to improve the welfare. Cognitive training prevents neurodegeneration processes and loss of hippocampal function, and provides improvements on performance of cognitive skills. However, remains unclear how training on a specific task affects another cognitive and emotional aspects. To evaluate the effects of training on spatial working memory task on anxiety, habituation and cell density in the hippocampus, we used aged and young rats trained in the working memory task (dependent of the hippocampus) or in a task with visible track (independent of the hippocampus) in the Morris water maze (MWM). After MWM training clousure the animals were exposed to the test and re−test in the elevated plus maze and the open field test. Subsenquently to behavioural tests animals were perfused and the hippocampus was processed for Nissl staining to quantify the density of hippocampal cells. The acquisition of the MWM task was disrrupted in aged animals submitted to working memory task and visible platform task, however the aged animals were capable to learn the task during the training and exhibit similar performance to youngest. Cognitive training on spatial working memory leads to reduction of anxiety-like behaviours in the elevated plus maze and modify habituation rate in the open field in aged rats compared to animals that were exposed to visible task. Although no differences were found in the hippocampus cell density between young and aged rats and also for different training. Cognitive training on the working memory version of MWM leads to decrease of anxiety levels and habituation rate in aged animals and could be an important tool to investigate plastic neural changes induced by training. (AU)

• FAPESP's process: 11/08035-2 - Influence of spatial learning on the temporal patterns of protein expression of BMAL1, CLOCK, PER1 and CREB in the hippocampus of aged rats
• Grantee: Aline Vilar Machado Nils
• Support Opportunities: Scholarships in Brazil - Doctorate