Faria Rodolfo Souza, Gutierres Luís Felipe Soares, Sobrinho Fernando César Faria, Miranda Iris do Vale, Reis Júlia Dos, Dias Elayne Vieira, Sartori Cesar Renato, Moreira Dalmo Antonio Ribeiro
Laboratory of Physiology, Faculty of Medicine of Itajubá-FMIt, São Vicente, Av. Renó Júnior, 368, Itajubá, MG 37502-138, Brazil.
Laboratory of Physiology, Faculty of Medicine of Itajubá-FMIt, São Vicente, Av. Renó Júnior, 368, Itajubá, MG 37502-138, Brazil.
Neurosci Lett. 2016 Aug 15;628:147-52. doi: 10.1016/j.neulet.2016.06.020. Epub 2016 Jun 18.
Exposure to negative environmental events triggers defensive behavior and leads to the formation of aversive associative memory. Cellular and molecular changes in the central nervous system underlie this memory formation, as well as the associated behavioral changes. In general, memory process is established in distinct phases such as acquisition, consolidation, evocation, persistence, and extinction of the acquired information. After exposure to a particular event, early changes in involved neural circuits support the memory consolidation, which corresponds to the short-term memory. Re-exposure to previously memorized events evokes the original memory, a process that is considered essential for the reactivation and consequent persistence of memory, ensuring that long-term memory is established. Different environmental stimuli may modulate the memory formation process, as well as their distinct phases. Among the different environmental stimuli able of modulating memory formation is the physical exercise which is a potent modulator of neuronal activity. There are many studies showing that physical exercise modulates learning and memory processes, mainly in the consolidation phase of the explicit memory. However, there are few reports in the literature regarding the role of physical exercise in implicit aversive associative memory, especially at the persistence phase. Thus, the present study aimed to investigate the relationship between swimming exercise and the consolidation and persistence of contextual and auditory-cued fear memory. Male Wistar rats were submitted to sessions of swimming exercise five times a week, over six weeks. After that, the rats were submitted to classical aversive conditioning training by a pairing tone/foot shock paradigm. Finally, rats were evaluated for consolidation and persistence of fear memory to both auditory and contextual cues. Our results demonstrate that classical aversive conditioning with tone/foot shock pairing induced consolidation as well as persistence of conditioned fear memory. In addition, rats submitted to swimming exercise over six weeks showed an improved performance in the test of auditory-cued fear memory persistence, but not in the test of contextual fear memory persistence. Moreover, no significant effect from swimming exercise was observed on consolidation of both contextual and auditory fear memory. So, our study, revealing the effect of the swimming exercise on different stages of implicit memory of tone/foot shock conditioning, contributes to and complements the current knowledge about the environmental modulation of memory process.
暴露于负面环境事件会引发防御行为，并导致厌恶联想记忆的形成。中枢神经系统中的细胞和分子变化是这种记忆形成以及相关行为变化的基础。一般来说，记忆过程是在不同阶段建立的，如获取、巩固、唤起、持续和消退所获取的信息。接触特定事件后，相关神经回路的早期变化支持记忆巩固，这对应于短期记忆。再次接触先前记忆的事件会唤起原始记忆，这一过程被认为对记忆的重新激活和随后的持续存在至关重要，确保长期记忆的建立。不同的环境刺激可能会调节记忆形成过程及其不同阶段。在能够调节记忆形成的不同环境刺激中，体育锻炼是神经元活动的有力调节因子。有许多研究表明，体育锻炼主要在显性记忆的巩固阶段调节学习和记忆过程。然而，关于体育锻炼在隐性厌恶联想记忆中的作用，尤其是在持续阶段，文献中报道较少。因此，本研究旨在探讨游泳锻炼与情境性和听觉提示性恐惧记忆的巩固及持续之间的关系。雄性Wistar大鼠每周进行五次游泳锻炼，持续六周。之后，通过音调/足部电击配对范式对大鼠进行经典厌恶条件训练。最后，评估大鼠对听觉和情境线索的恐惧记忆的巩固和持续情况。我们的结果表明，音调/足部电击配对的经典厌恶条件训练诱导了条件性恐惧记忆的巩固和持续。此外，进行六周游泳锻炼的大鼠在听觉提示性恐惧记忆持续测试中的表现有所改善，但在情境性恐惧记忆持续测试中没有改善。此外，未观察到游泳锻炼对情境性和听觉恐惧记忆巩固有显著影响。所以，我们的研究揭示了游泳锻炼对音调/足部电击条件反射隐性记忆不同阶段的影响，有助于补充和完善当前关于记忆过程环境调节的知识。
