A área hipocampal CA1 é essencial para a memória similar à episódica

• Ano de defesa: 2016
• Autor(a) principal: Barreto, Davi Drieskens Carvalho de Castro Sá
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Psicologia; Programa de Pós-Graduação em Neurociência Cognitiva e Comportamento; UFPB
• Palavras-chave em Português: Memória similar à episódica; Hipocampo; CA1; Muscimol; Exploração de objetos; Episodic-like memory; Hippocampus; CA1; Muscimol; Objects exploration; CIENCIAS HUMANAS::PSICOLOGIA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/8549

Episodic memory is a declarative type of memory rich in temporal and spatial contexts. This type of memory has been atributed only to humans, but animals have been demonstrating an episodic-like memory, based on behavioural criteria and, considered as a memory for a particular event (“what”) that happened in a particular place (“where”) and in a particular time (“when”). To be considered as an episodic-like memory, these behavioural aspects must be evoked in an integrative and associative way, excluding any possibility of being evoked separately. For a long time it has been demonstrated that the medial temporal lobe (MTL) is important for processes involving episodic-like memory characteristics and, the hippocampus and other areas, such as the perirhinal, postrhinal, entorhinal and medial prefrontal cortices seem to be involved in one or more of episodic-like memory behavioural aspects. In this work we sought to investigate the role of the hippocampal subfield CA1 with bilateral infusions of the GABAA agonist muscimol, in an integrative episodic-like memory task. 24 naïve male wistar rats, ranging from 3 to 4 months, weighing 270-360g and kept in controlled coditions, were used as subjects. This task is done in an open-field and it depends on the tendency of rats to explore novelty. There were three trials: sample 1, sample 2 and test. Each one had a duration of five minutes and the intertrial interval was of 1 hour. In sample 1, rats were allowed to explore four novel objects (A) in specific locations. In sample 2, four new objects (B) were disposed in the open-field, where two of them were placed in locations previously occupied by objects “A”, and two of them were placed in new positions. In the test trial, animals were exposed to four copies of previously seen objects, where two of them were stationary to its initial position (A1 and B1) and another two were displaced (A2 and B2). The pattern of exploration expected to this task is of A1>B1 (temporal pattern), B2>B1 (spatial pattern) and A1>A2 (integrative pattern). Animals of the control group did evoked an episodic-like memory in the test trial, while the animals in the experimental group didn’t. This was not influenced by a lack of exploration in the muscimol group. Histology showed that the cannulae and niddle tips were placed in the right positions. Altogether, our data provides evidence that CA1 plays an essential role in the recollection of the episodic-like memory components, although it’s not clear if it does by having a role in the recognition of objects alone, or on the association of temporal and spatial aspects of episodic-like memory.