Navegando por Palavras-chave "fear conditioning"
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- ItemSomente MetadadadosEffects of nociceptin/orphanin FQ in the acquisition of contextual and tone fear conditioning in rats(Amer Psychological Assoc, 2008-02-01) Fornari, Raquel V. [UNIFESP]; Soares, Juliana C. K. [UNIFESP]; Ferreira, Tatiana L. [UNIFESP]; Moreira, Karin M. [UNIFESP]; Oliveira, Maria G. M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Nociceptin, or orphanin FQ (N/OFQ), the endogenous ligand of NOP receptors, is known to regulate learning and memory processes. To verify the role of N/OFQ in the acquisition of contextual (CFC) and tone fear conditioning (TFC), Wistar male rats received intracerebroventricular injections of N/OFQ (0.1-5.0 nmol) before training, and were tested 24 and 48 hr later to access the freezing response to context and tone, respectively. the intermediate doses (1.0 and 2.5 nmol) impaired the CFC test, sparing TFC. the highest dose (5.0 nmol) reduced freezing during both tests, a result that may be due to nonspecific effects. the posttraining injection of N/OFQ (1 or 5 nmol) did not interfere with CFC and TFC, suggesting a specific effect of the peptide in acquisition processes. Moreover, the impairment observed with N/OFQ (1 nmol) in CFC cannot be attributed to a state-dependent learning because it was not reversed by its pretest administration. the data support the negative role of N/OFQ in the acquisition of aversively motivated tasks, which encompass a spatial component and depend on the hippocampus.
- ItemSomente MetadadadosEffects of Pre or Posttraining Dorsal Hippocampus D-AP5 Injection on Fear Conditioning to Tone, Background, and Foreground Context(Wiley-Blackwell, 2008-01-01) Schenberg, Eduardo Ekman [UNIFESP]; Menezes Oliveira, Maria Gabriela [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)NMDA receptor antagonist D-AP5 was injected into the dorsal hippocampus of Wistar rats before or immediately after the training session in fear conditioning. Training was conducted both with signaled (background context) or unsignaled (foreground context) footshocks. Contextual fear conditioning was assessed 24 h later and tone fear conditioning 48 h after training (only in the signaled footshock condition). Pretraining injections impaired conditioned fear to contextual features, both in background and foreground configurations, whereas tone fear conditioning was left intact. Posttraining injections were ineffective in all cases. We conclude that dorsal hippocampal NMDA receptors are required for contextual fear acquisition independently of context saliency and that they are not required to early consolidation processes. (C) 2008 Wiley-Liss, Inc.
- ItemSomente MetadadadosEffects of pre- or post-training entorhinal cortex AP5 injection on fear conditioning(Elsevier B.V., 2005-11-15) Schenberg, E. E.; Soares, JCK; Oliveira, MGM; Universidade Federal de São Paulo (UNIFESP)Fear conditioning is one of the most studied paradigms to assess the neural basis of emotional memory. the circuitry involves NNMA receptor activation in the amygdala and, in the case of contextual conditioning, in the hippocampus. Entorhinal cortex is one of the major input/output structures to the hippocampus and also projects to the amygdala, both through glutamatergic transmission. Other learning tasks involving hippocampus and amygdala, such as inhibitory avoidance, require entorhinal cortex during acquisition and consolidation. However, the involvement of NMDA receptors mediated transmission in entorhinal cortex in fear conditioning acquisition and consolidation is not clear. To investigate that issue, rats were trained in fear conditioning to both contextual and tone conditioned stimulus. Immediately before, immediately, 30 or 90 min after training they received NMDA antagonist AP5 or saline injections bilaterally in the entorhinal cortex (AP-6.8 mm, L +/- 5.0 mm DV-6.8 mm). Contextual fear conditioning was measured 24 h after training, and tone fear conditioning 48 h after training. AP5 injections selectively impaired contextual fear conditioning only when injected pre-training. Post-training injections had no effect. These findings suggest that entorhinal cortex NMDA receptors are necessary for acquisition, but not for consolidation, of contextual fear conditioning. On the other hand, both acquisition and consolidation of tone fear conditioning seem to be independent of NMDA receptors in the entorhinal cortex. (c) 2005 Elsevier Inc. All fights reserved.
- ItemSomente MetadadadosEffects of the M1 Muscarinic Antagonist Dicyclomine on Emotional Memory Retrieval(Amer Psychological Assoc, 2016) Soares, Juliana Carlota Kramer [UNIFESP]; Perfetto, Juliano Genaro [UNIFESP]; Antonio, Bruno Brito [UNIFESP]; Oliveira, Maria Gabriela Menezes [UNIFESP]Extensive research has shown the involvement of the central cholinergic system in the acquisition and consolidation of tasks involving conditioned fear responses, such as those observed in contextual fear conditioning (CFC), tone fear conditioning (TFC) and inhibitory avoidance (IA). However, there are few data concerning the role of this system in the memory retrieval process. Therefore, the present study aimed to compare the effects of the administration of an M1 antagonist on retrieval during these tasks. For each behavioral procedure, groups of male Wistar rats were trained. Twenty-four hr later, they were treated with different doses of dicyclomine (16, 32, or 64 mg/kg, i.p.) or with saline 30 min before the test session. The results showed that dicyclomine at doses of 16 and 32 mg/kg impaired CFC without interfering with IA performance. Moreover, only 64 mg/kg impaired TFC. These data suggest that M1 muscarinic receptors contribute to memory retrieval in CFC and TFC but are not essential for retrieval in IA.
- ItemSomente MetadadadosEffects of the M1 Muscarinic Antagonist Dicyclomine on Emotional Memory Retrieval(Amer Psychological Assoc, 2016) Soares, Juliana Carlota Kramer [UNIFESP]; Perfetto, Juliano Genaro [UNIFESP]; Antonio, Bruno Brito [UNIFESP]; Oliveira, Maria Gabriela Menezes [UNIFESP]Extensive research has shown the involvement of the central cholinergic system in the acquisition and consolidation of tasks involving conditioned fear responses, such as those observed in contextual fear conditioning (CFC), tone fear conditioning (TFC) and inhibitory avoidance (IA). However, there are few data concerning the role of this system in the memory retrieval process. Therefore, the present study aimed to compare the effects of the administration of an M1 antagonist on retrieval during these tasks. For each behavioral procedure, groups of male Wistar rats were trained. Twenty-four hr later, they were treated with different doses of dicyclomine (16, 32, or 64 mg/kg, i.p.) or with saline 30 min before the test session. The results showed that dicyclomine at doses of 16 and 32 mg/kg impaired CFC without interfering with IA performance. Moreover, only 64 mg/kg impaired TFC. These data suggest that M1 muscarinic receptors contribute to memory retrieval in CFC and TFC but are not essential for retrieval in IA.
- ItemSomente MetadadadosFear conditioning performance and NMDA receptor subtypes: NR2A differential expression in the striatum(Elsevier B.V., 2006-04-28) Schenberg, E. E.; Ferreira, T. L.; Figueredo, L. Z.; Hipolide, D. C.; Nobrega, J. N.; Oliveira, MGM; Universidade Federal de São Paulo (UNIFESP); Ctr Addict & Mental HlthWhile considerable evidence implicates NMDA receptors in the hippocampus in contextual fear conditioning, the role of other brain regions is less well understood. To further investigate this issue, rats were subjected to a contextual fear conditioning task and then classified as high or low responders according to performance. Density of NMDA receptors was evaluated using [H-3]MK-801 autoradiography in 52 brain areas and expression of NR2A and NR2B subunits was studied with in situ hybridization in the same brains. Results revealed no differences between high- and low-performance rats in NMDA receptor binding in any of the brain areas studied. Similarly, NR2B subunit expression was also not different between groups. However, NR2A expression was significantly higher in the caudate-putamen of low-performance rats. These results suggest that NMDA receptors in the caudate-putamen may also be involved in contextual fear conditioning performance. (c) 2006 Elsevier Inc. All rights reserved.
- ItemSomente MetadadadosIs behavioral sensitization to ethanol associated with contextual conditioning in mice?(Lippincott Williams & Wilkins, 2003-03-01) Quadros, IMH; Souza-Formigoni, MLO; Fornari, R. V.; Nobrega, J. N.; Oliveira, MGM; Universidade Federal de São Paulo (UNIFESP); Ctr Addict & Mental HlthBehavioral sensitization to drugs of abuse seems to involve learning processes. in mice, ethanol-induced locomotor sensitization is potentiated by repeated pairing of ethanol (EtOH) injections and the testing chamber. the present study aimed to test: (1) the association between the performance in a contextual conditioning task and the development of behavioral sensitization to EtOH in mice; (2) whether EtOH sensitization would be expressed in a different testing environment. Male albino Swiss mice (n = 72) were initially submitted to a contextual fear conditioning task. After 2 weeks without manipulation, the animals received daily i.p. injections of 2.2 g/kg EtOH (n = 52) or saline (n = 20), for 21 days. They were tested weekly for locomotor activity in activity cages. After 1 week of withdrawal, all mice received 2.2 g/kg EtOH and had their locomotor activity recorded in an open-field. According to the locomotor behavior displayed along the 21-day treatment, EtOH-treated mice were classified as sensitized (n = 15) or non-sensitized (n = 15). When these subgroups and saline-treated mice were compared for the freezing response in the conditioning test, sensitized mice displayed a greater freezing time than non-sensitized mice. When challenged with EtOH in the open-field, none of the EtOH-treated subgroups expressed behavioral sensitization. These results suggest that the development of EtOH sensitization seems to be positively associated with contextual learning, and further confirms that the expression of sensitization is highly dependent on contextual cues.
- ItemAcesso aberto (Open Access)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.
- ItemSomente MetadadadosRole of muscarinic M1 receptors in inhibitory avoidance and contextual fear conditioning(Elsevier B.V., 2006-09-01) Kramer Soares, Juliana Carlota; Fornari, Raquel Vecchio; Menezes Oliveira, Maria Gabriela; Universidade Federal de São Paulo (UNIFESP)The objective of the present study was to observe the effects of pre-training or post-training administration of dicyclomine, a M1 muscarinic antagonist, on inhibitory avoidance (IA) and contextual fear conditioning (CFC) and to investigate if the effects observed with the pre-training administration of dicyclomine are state-dependent. for each behavioral procedure (IA and CFC) groups of Wistar male rats were treated with saline or dicyclomine either 30 min before training (pre-training), immediately after training or 30 min before training/30 min before test (pre-training/pre-test). the animals were tested 24 h after training. the acquisition of IA and CFC was impaired by pre-training administration of dicyclomine. the consolidation of both tasks was not affected by dicyclomine given immediately after training. Pre-training/pre-test administration of dicyclomine impaired both tasks, an effect similar to that observed in the group which only received pre-training administration. Pre-test treatment induced dissociation between both tasks, impairing CFC retrieval, without interfering with the animals avoidance response. These results show that the dicyclomine did not affect IA and CFC consolidation, suggesting specific involvement of M1 muscarinic receptor only in acquisition these tasks, and these effects was not state-dependent. However, it is possible that the retrieval of these tasks may be mediated, at least in part, by different neurochemical mechanisms and may be dissociated by dicyclomine. (c) 2006 Elsevier Inc. All rights reserved.