Navegando por Palavras-chave "retrieval"

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    Effects of sleep deprivation on different phases of memory in the rat: dissociation between contextual and tone fear conditioning tasks
    (Frontiers Research Foundation, 2014-11-07) Rossi, Vanessa Contatto [UNIFESP]; Tiba, Paula Ayako; Monreira, Karin Di Monteiro; Ferreira, Tatiana Lima; Oliveira, Maria Gabriela Menezes de [UNIFESP]; Suchecki, Deborah [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Federal do ABC (UFABC)
    Numerous studies show that sleep deprivation (SD) impacts negatively on cognitive processes, including learning and memory. Memory formation encompasses distinct phases of which acquisition, consolidation and retrieval are better known. Previous studies with pre-training SD induced by the platform method have shown impairment in fear conditioning tasks. Nonetheless, pre-training manipulations do not allow the distinction between effects on acquisition and/or consolidation, interfering, ultimately, on recall of/performance in the task. in the present study, animals were first trained in contextual and tone fear conditioning (TFC) tasks and then submitted to SD with the purpose to evaluate the effect of this manipulation on different stages of the learning process, e.g., in the uptake of (new) information during learning, its encoding and stabilization, and the recall of stored memories. Besides, we also investigated the effect of SD in the extinction of fear memory and a possible state dependent learning induced by this manipulation. for each task (contextual or TFC), animals were trained and then distributed into control, not sleep-deprived (CTL) and SD groups, the latter being submitted to the modified multiple platform paradigm for 96 h. Subsets of eight rats in each group/experiment were submitted to the test of the tasks, either immediately or at different time intervals after SD. the results indicated that (a) pre- but not post-training SD impaired recall in the contextual and TFC; (b) this impairment was not state-dependent; and (c) in the contextual fear conditioning (CFC), pre-test SD prevented extinction of the learned task. Overall, these results suggest that SD interferes with acquisition, recall and extinction, but not necessarily with consolidation of emotional memory.
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    Modafinil Prevents Inhibitory Avoidance Memory Deficit Induced by Sleep Deprivation in Rats
    (Amer Acad Sleep Medicine, 2010-07-01) Moreira, Karin Monteiro [UNIFESP]; Ferreira, Tatiana Lima [UNIFESP]; Hipólide, Débora Cristina [UNIFESP]; Fomari, Raquel Vecchio [UNIFESP]; Tufik, Sergio [UNIFESP]; Menezes Oliveira, Maria Gabriela [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Federal do ABC (UFABC); Univ Groningen, Univ Med Ctr Groningen
    Study Objectives: Evaluation of modafinil effects on the inhibitory avoidance task (IA).Design: Rats were trained on a multiple trial IA task after receiving modafinil or vehicle injections. In experiment 1 they were trained with a weak protocol under baseline condition and in experiment 2, with a stronger protocol under sleep-deprivation condition.Results: In experiment 1 modafinil improved rats' acquisition whereas the retention test remained unaffected. In Experiment 2 modafinil did not interfere with training performance, but the lower dose prevented the retention impairment in sleep-deprived animals.Conclusions: Modafinil is able to improve acquisition in normal rats and reverse the long-term memory impairment induced by sleep-deprivation.
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    Pre-test metyrapone impairs memory recall in fear conditioning tasks: lack of interaction with I--adrenergic activity
    (Frontiers Research Foundation, 2015-03-03) Careaga, Mariella Bodemeier Loayza [UNIFESP]; Tiba, Paula Ayako; Ota, Simone Marie [UNIFESP]; Suchecki, Deborah [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Federal do ABC (UFABC)
    Cognitive processes, such as learning and memory, are essential for our adaptation to environmental changes and consequently for survival. Numerous studies indicate that hormones secreted during stressful situations, such as glucocorticoids (GCs), adrenaline and noradrenaline, regulate memory functions, modulating aversive memory consolidation and retrieval, in an interactive and complementary way. Thus, the facilitatory effects of GCs on memory consolidation as well as their suppressive effects on retrieval are substantially explained by this interaction. On the other hand, low levels of GCs are also associated with negative effects on memory consolidation and retrieval and the mechanisms involved are not well understood. the present study sought to investigate the consequences of blocking the rise of GCs on fear memory retrieval in multiple tests, assessing the participation of (3-adrenergic signaling on this effect. Metyrapone (GCs synthesis inhibitor; 75 mg/kg), administered 90 min before the first test of contextual or tone fear conditioning (TFC), negatively affected animals' performances, but this effect did not persist on a subsequent test, when the conditioned response was again expressed. This result suggested that the treatment impaired fear memory retrieval during the first evaluation. the administration immediately after the first test did not affect the animals' performances in contextual fear conditioning (CFC), suggesting that the drug did not interfere with processes triggered by memory reactivation. Moreover, metyrapone effects were independent of beta-adrenergic signaling, since concurrent administration with propranolol (2 mg/kg), alpha,beta-adrenergic antagonist, did not modify the effects induced by metyrapone alone. These results demonstrate that pre-test metyrapone administration led to negative effects on fear memory retrieval and this action was independent of a beta-adrenergic signaling.
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    Role of state-dependent learning in the cognitive effects of caffeine in mice
    (Cambridge Univ Press, 2013-08-01) Sanday, Leandro [UNIFESP]; Zanin, Karina Agustini [UNIFESP]; Patti, Camilla de Lima [UNIFESP]; Fernandes-Santos, Luciano [UNIFESP]; Oliveira, Larissa C. [UNIFESP]; Longo, Beatriz Monteiro [UNIFESP]; Andersen, Monica Levy [UNIFESP]; Tufik, Sergio [UNIFESP]; Frussa-Filho, Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Caffeine is the most widely used psychoactive substance in the world and it is generally believed that it promotes beneficial effects on cognitive performance. However, there is also evidence suggesting that caffeine has inhibitory effects on learning and memory. Considering that caffeine may have anxiogenic effects, thus changing the emotional state of the subjects, state-dependent learning may play a role in caffeine-induced cognitive alterations. Mice were administered 20 mg/kg caffeine before training and/or before testing both in the plus-maze discriminative avoidance task (an animal model that concomitantly evaluates learning, memory, anxiety-like behaviour and general activity) and in the inhibitory avoidance task, a classic paradigm for evaluating memory in rodents. Pre-training caffeine administration did not modify learning, but produced an anxiogenic effect and impaired memory retention. While pre-test administration of caffeine did not modify retrieval on its own, the pre-test administration counteracted the memory deficit induced by the pre-training caffeine injection in both the plus-maze discriminative and inhibitory avoidance tasks. Our data demonstrate that caffeine-induced memory deficits are critically related to state-dependent learning, reinforcing the importance of considering the participation of state-dependency on the interpretation of the cognitive effects of caffeine. the possible participation of caffeine-induced anxiety alterations in state-dependent memory deficits is discussed.