首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Terms such as ‘exist’, ‘actual’, etc., (hereafter, “ontic terms”) are recognized as having uses that are not ontologically committing, in addition to the usual commissive uses. (Consider, e.g., the Platonic and the neutral readings of ‘There is an even prime’.) In this paper, I identify five different noncommissive uses for ontic terms, and (by a kind of via negativa) attempt to define the commissive use, focusing on ‘actual’ as my example. The problem, however, is that the resulting definiens for the commissive ‘actual’ is itself equivocal between a commissive and a noncommissive reading. I thus consider other proposals for defining the commissive use, including two proposals from David Lewis. However, each proposal is found to be equivocal in the same way—and eventually I argue that it is impossible to define an ontic term unequivocally. Even so, this is not meant to overshadow that we can understand an ontic term as univocally commissive, in certain conversational contexts. I close by illustrating the import of these observations for the Hirsch–Sider debate in metaontology.  相似文献   

2.
Cyclic AMP response element binding protein (CREB) plays a critical role in fear memory formation. Here we determined the role of CREB selectively within the amygdala in reconsolidation and extinction of auditory fear. Viral overexpression of the inducible cAMP early repressor (ICER) or the dominant-negative mCREB, specifically within the lateral amygdala disrupted reconsolidation of auditory fear memories. In contrast, manipulations of CREB in the amygdala did not modify extinction of fear. These findings suggest that the role of CREB in modulation of memory after retrieval is dynamic and that CREB activity in the basolateral amygdala is involved in fear memory reconsolidation.  相似文献   

3.
According to the Unexpected-Event Hypothesis (UEH) (Frensch, Haider, Rünger, Neugebauer, Voigt & Werg, 2002), conflicts between expected and actually performed behaviors trigger attribution processes and ultimately lead to the ability to verbally report an incidentally experienced sequential regularity. In two experiments, we manipulated the likelihood that a specific conflict, a premature response, occurred in a sequential version of the Number Reduction Task (NRT). Experiment 1 demonstrated that a longer RSI leads to a larger number of premature responses and to more verbal report than a shorter RSI. However, this effect of the RSI on verbal report was removed when participants were discouraged from emitting premature responses. Experiment 2 revealed that artificially inducing premature responses leads to an increase in verbal report, but only when premature responses are introduced late in training. Overall, the findings strongly support the assumptions of the UEH.  相似文献   

4.
Ample evidence suggests that consolidated memories, upon their retrieval, enter a labile state, in which they might be susceptible to change. It has been proposed that memory labilization allows for the integration of relevant information in the established memory trace (memory updating). Memory labilization and reconsolidation do not necessarily occur when a memory is being reactivated, but only when there is something to be learned during memory retrieval (prediction error). Thus, updating of a fear memory trace should not occur under retrieval conditions in which the outcome is fully predictable (no prediction error). Here, we addressed this issue, using a human differential fear conditioning procedure, by eliminating the very possibility of reinforcement of the reminder cue. A previously established fear memory (picture-shock pairings) was reactivated with shock-electrodes attached (Propranolol group, n=18) or unattached (Propranolol No-Shock Expectation group, n=19). We additionally tested a placebo-control group with the shock-electrodes attached (Placebo group, n=18). Reconsolidation was not triggered when nothing could be learned during the reminder trial, as noradrenergic blockade did not affect expression of the fear memory 24h later in the Propranolol No-Shock Expectation group. Only when the outcome of the retrieval cue was not fully predictable, propranolol, contrary to placebo, reduced the startle fear response and prevented the return of fear (reinstatement) the following day. In line with previous studies, skin conductance response and shock expectancies were not affected by propranolol. Remarkably, a double dissociation emerged between the emotional (startle response) and more cognitive expression (expectancies, SCR) of the fear memory. Our findings have important implications for reconsolidation blockade as treatment strategy for emotional disorders. First, fear reducing procedures that target the emotional component of fear memory do not necessarily affect the cognitive component and vice versa. Second, mere retrieval of the fear memory is not sufficient to induce its labilization and reconsolidation.  相似文献   

5.
Advances in both experimental neuroscience and psychoanalytic theory and technique have made it possible to consider mechanisms by which psychodynamic psychotherapies might have an impact at the cellular and molecular level. Here potential analogies are drawn between (1) the mechanisms and results of blocking the reconsolidation of conditioned fear memories in the laboratory and (2) several key aspects of psychoanalytic process. A review of the biology of conditioned fear memory, including differences between extinction and inhibition of reconsolidation, indicates that this biology may have relevance to various ways in which psychoanalytic therapy is effective. The ideas proposed here might lead to further experimental attempts to understand the molecular biology of psychoanalysis.  相似文献   

6.
Both the acquisition and the extinction of memories leave short- and long-term mnemonic traces. Here, we show that in male Wistar rats, the short-term memory for a step-down inhibitory avoidance task (IA) is resistant to extinction, and that its expression does not influence retrieval or extinction of long-term memory. It has been known for some time that short- and long-term inhibitory avoidance memory involve separate and parallel processes. Here we show that, instead, short-term extinction of IA long-term memory is the first step towards its long-term extinction, and that this link requires functional NMDA receptors and protein synthesis in the CA1 region of the dorsal hippocampus at the time of the first CS-no US presentation.  相似文献   

7.
Contexts and discrete cues associated with drug-taking are often responsible for relapse among addicts. Animal models have shown that interference with the reconsolidation of drug-cue memories can reduce seeking of drugs or drug-paired stimuli. One such model is conditioned place preference (CPP) in which an animal is trained to associate a particular environment with the rewarding effects of a drug. Previous work from this laboratory has shown that intra-nucleus accumbens core infusions of a MEK inhibitor can interfere with reconsolidation of these drug-cue memories. A question that remains is whether post-retrieval drug effects on subsequent memories represent an interference with reconsolidation processes or rather a facilitation of extinction. In this experiment, we explore the effect of post-retrieval injections of propranolol, a beta-adrenergic receptor antagonist, on reconsolidation and extinction of cocaine CPP. After acquisition of cocaine CPP, animals were given post-retrieval propranolol injections once or each day during a protocol of unreinforced preference tests, until the animals showed no preference for the previously cocaine-paired environment. Following a cocaine priming injection, the animals that received daily post-test propranolol injections did not reinstate their preference for the drug-paired side. In contrast, a single post-retrieval propranolol injection followed by multiple days of unreinforced preference tests failed to blunt subsequent cocaine reinstatement of the memory. These data suggest that daily post-retrieval systemic injections of propranolol decrease the conditioned preference by interfering with reconsolidation of the memory for the association between the drug-paired side and the reinforcing effects of the drug, rather than facilitating new extinction learning.  相似文献   

8.
Contextual stimulus control over instrumental drug-seeking behavior relies on the reconsolidation of context-response-drug associative memories into long-term memory storage following retrieval-induced destabilization. According to previous studies, the basolateral amygdala (BLA) and dorsal hippocampus (DH) regulate cocaine-related memory reconsolidation; however, it is not known whether these brain regions interact or independently control this phenomenon. To investigate this question, rats were trained to lever press for cocaine reinforcement in a distinct environmental context followed by extinction training in a different context. Rats were then briefly re-exposed to the cocaine-paired context to destabilize cocaine-related memories, or they were exposed to an unpaired context. Immediately thereafter, the rats received unilateral microinfusions of anisomycin (ANI) into the BLA plus baclofen/muscimol (B/M) into the contralateral (BLA/DH disconnection) or ipsilateral DH, or they received contralateral or ipsilateral microinfusions of vehicle. They then remained in their home cages overnight or for 21 d, followed by additional extinction training and a test of cocaine-seeking behavior (nonreinforced active lever responding). BLA/DH disconnection following re-exposure to the cocaine-paired context, but not the unpaired context, impaired subsequent drug context-induced cocaine-seeking behavior relative to vehicle or ipsilateral ANI + B/M treatment. Prolonged home cage stay elicited a time-dependent increase, or incubation, of drug-context-induced cocaine-seeking behavior, and BLA/DH disconnection inhibited this incubation effect despite some recovery of cocaine-seeking behavior. Thus, the BLA and DH interact to regulate the reconsolidation of cocaine-related associative memories, thereby facilitating the ability of drug-paired contexts to trigger cocaine-seeking behavior and contributing to the incubation of cocaine-seeking behavior.  相似文献   

9.
10.
Memantine is a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist that has been approved for the treatment of the cognitive deficits noted in Alzheimer's disease. While there is a body of research that supports memantine's facilitative action upon memory compromise, this series of studies aimed to investigate the effects of this drug in healthy animals with intact memory functioning. A 0.1 mM dose of memantine injected immediately after a weakly aversive training event (i.e. 20% v/v methyl anthranilate) was found to enhance passive avoidance learning for this event in day-old chicks up to 24 h following training. The same dose of memantine was also observed to enhance memory for the training event when it was administered in conjunction with a reminder trial. These results suggest that memantine is capable of facilitating both memory consolidation as well as memory reconsolidation. It was concluded that memantine's mechanism may involve the short-term or intermediate memory phases of the Gibbs and Ng model of memory, and that the current findings represent enhancement of intact memory, rather than amelioration of memory compromise.  相似文献   

11.
Mammalian target of rapamycin (mTOR), a central regulator of protein synthesis in neurons, has been implicated in synaptic plasticity and memory. Here we show that mTOR inhibition by rapamycin in the basolateral amygdala (BLA) or dorsal hippocampus (DH) impairs both formation and reconsolidation of memory for inhibitory avoidance (IA) in rats. Male Wistar rats received bilateral infusions of vehicle or rapamycin into the BLA or DH before or after IA training or retrieval. Memory retention was tested at different time points after drug infusion. Rapamycin impaired long-term IA retention when given before or immediately after training or retrieval into the BLA. When infused into the DH, rapamycin produced memory impairment when given before training or immediately after retrieval. The impairing effects of post-retrieval rapamycin required memory retrieval and were not reversed by a reminder shock. The results provide the first evidence that mTOR in the BLA and DH might play a role in IA memory reconsolidation.  相似文献   

12.
Histone modifications contribute to the epigenetic regulation of gene expression, a process now recognized to be important for the consolidation of long-term memory. Valproic acid (VPA), used for many years as an anticonvulsant and a mood stabilizer, has effects on learning and memory and enhances the extinction of conditioned fear through its function as a histone deacetylase inhibitor (HDAC). Here we report that VPA enhances long-term memory for both acquisition and extinction of cued-fear. Interestingly, VPA enhances extinction, but also enhances renewal of the original conditioned fear when tested in a within-subjects design. This effect appears to be related to a reconsolidation-like process since a single CS reminder in the presence of VPA can enhance long-term memory for the original fear in the context in which fear conditioning takes place. We also show that by modifying the intertrial interval during extinction training, VPA can strengthen reconsolidation of the original fear memory or enhance long-term memory for extinction such that it becomes independent of context. These findings have important implications for the use of HDAC inhibitors as adjuncts to behavior therapy in the treatment of phobia and related anxiety disorders.  相似文献   

13.
A considerable literature has shown deficits in memory resulting from the administration of protein synthesis inhibitors; however, most of the past literature in this field has focused on acquisition of new memory using aversively-motivated tasks. The effect of protein synthesis inhibition on appetitive learning and memory as well as extinction is less clear. The present study employed an appetitive odor discrimination paradigm to examine the effects of acute cycloheximide administration (1 mg/kg) on reconsolidation and extinction.Male, Long-Evans adult rats were trained to discriminate between two odors (i.e., cocoa and cinnamon) and then received extinction trials following an intraperitoneal injection of cycloheximide or vehicle. Twenty-four hours later, rats were tested via one non-reinforced test trial. Results showed amnesia for extinction as well as original training (i.e., correct odor choice) in cycloheximide-injected rats in this appetitive task, while vehicle-injected controls showed good memory for extinction. These data add to a growing literature showing the importance of protein synthesis inhibition for extinction and reconsolidation in appetitive learning and memory.  相似文献   

14.
Memory reconsolidation is defined as a process in which the retrieval of a previously consolidated memory returns to a labile state which is then subject to stabilization. The reminder is the event that begins with the presentation of the learned cue and triggers the labilization-reconsolidation process. Since the early formulation of the hypothesis, several controversial items have arisen concerning the conditions that define reconsolidation. It is herein proposed that two diagnostic features characterize reconsolidation, namely: the labilization of the reactivated memory and the specificity of the reminder structure. To study this proposal, subjects received two different training sessions on verbal material on Day 1 and Day 2, respectively. Finally, they were tested for the first and second acquired memories on Day 3. It is demonstrated that the human declarative memory fulfills the two requirements that define the process. First, the reactivated memory is impaired by a new learning only when it is given closely after the reminder, revealing that the memory is labilized. Second, the omission of at least one of the reminder's components prevents labilization. Therefore, results show that the new learning fails to produce an amnesic effect on the target memory either when the reminder omits the learned cue or includes the beginning of the reinforcement.  相似文献   

15.
Conclusion The contention is that in providing an account of the intervention process beyond the usual parameters of reporting, Weinstein and her colleagues have helped bring to the fore issues in the conduct and reporting of intervention research which are anomalous to most current theories and accounts. Taken seriously, the issues openly discussed could provide a useful step toward reducing the discrepancy between how we carry out interventions and how we say we carry out interventions. Through attempts to incorporate these issues into theory, we increase the verisimilitude of our ideas and develop a more differentiated filter for our community work. If, as Cronbach asserts, social science is cumulative, not in possessing ever-more refined answers about fixed questions, but in possessing an ever-richer repertoire of questions (1986, p. 91), accounts such as those provided by Weinstein and her colleagues can indeed serve as a heuristic for theory by telling it like it was.  相似文献   

16.
Accumulating evidence indicates the key role of alpha-calcium/calmodulin-dependent protein kinase II (alphaCaMKII) in synaptic plasticity and learning, but it remains unclear how this kinase participates in the processing of memory extinction. Here, we investigated the mechanism by which alphaCaMKII may mediate extinction by using heterozygous knock-in mice with a targeted T286A mutation that prevents the autophosphorylation of this kinase (alphaCaMKII(T286A+/-)). Remarkably, partial reduction of alphaCaMKII function due to the T286A(+/-) mutation prevented the development of extinction without interfering with initial hippocampus-dependent memory formation as assessed by contextual fear conditioning and the Morris water maze. It is hypothesized that the mechanism of extinction may differ depending on the interval at which extinction training is started, being more akin to "new learning" at longer intervals and "unlearning" or "erasure" at shorter intervals. Consistent with this hypothesis, we found that extinction conducted 24 h, but not 15 min, after contextual fear training showed spontaneous recovery (reappearance of extinguished freezing responses) 21 d following the extinction, representing behavioral evidence for new learning and unlearning mechanisms underlying extinction 24 h and 15 min post-training, respectively. Importantly, the alphaCaMKII(T286A+/-) mutation blocked new learning of contextual fear memory extinction, whereas it did not interfere with unlearning processes. Our results demonstrate a genetic dissociation of new learning and unlearning mechanisms of extinction, and suggest that alphaCaMKII is responsible for extinguishing memories specifically through new learning mechanisms.  相似文献   

17.
This article emphasizes the development of formulations as a framework from which leaders can intervene effectively in assisting groups to work toward their stated goals. The concept of formulation, used as a teaching tool to help students and supervisees conceptualize group issues, is presented, as is a schema whose purpose is to teach steps leading to clear formulations. The schema simplifies, for the purposes of teaching and supervision, the complex process used by experienced group therapists as a basis for interventions. The schema emphasizes perception, affect, cognition, validation, intervention, and evaluation. Here-and-now processes, conscious and unconscious mechanisms, and group affect also are stressed.  相似文献   

18.
外派人员与组织的期望匹配模式对绩效的影响   总被引:2,自引:0,他引:2  
外派个人与组织的期望具有四种可能的匹配关系。本研究构建了四种关系的概念模型并进行了效度验证。研究数据采自多种行业跨国公司的两组样本,结构方程建模的分析结果表明,构思关系具有良好的诺姆网络效度,个体-组织期望的不同组合模式对外派的绩效有显著影响。该研究结果对于外派经理及其所在的组织都具有重要意义。  相似文献   

19.
A distributed limbic-corticostriatal circuitry is implicated in cue-induced drug craving and relapse. Exposure to drug-paired cues not only precipitates relapse, but also triggers the reactivation and reconsolidation of the cue-drug memory. However, the limbic cortical-striatal circuitry underlying drug memory reconsolidation is unclear. The aim of this study was to investigate the involvement of the nucleus accumbens core and the basolateral amygdala in the reconsolidation of a cocaine-conditioned stimulus-evoked memory. Antisense oligodeoxynucleotides (ASO) were infused into each structure to knock down the expression of the immediate-early gene zif268, which is known to be required for memory reconsolidation. Control infusions used missense oligodeoxynucleotides (MSO). The effects of zif268 knockdown were measured in two complementary paradigms widely used to assess the impact of drug-paired CSs upon drug seeking: the acquisition of a new instrumental response with conditioned reinforcement and conditioned place preference. The results show that both intranucleus accumbens core and intrabasolateral amygdala zif268 ASO infusions at memory reactivation impaired the reconsolidation of the memory underlying a cocaine-conditioned place preference. However, knockdown of zif268 in the nucleus accumbens at memory reactivation had no effect on the memory underlying the conditioned reinforcing properties of the cocaine-paired CS measured subsequently, and this is in contrast to the marked impairment observed previously following intrabasolateral amygdala zif268 ASO infusions. These results suggest that both the basolateral amygdala and nucleus accumbens core are key structures within limbic cortical-striatal circuitry where reconsolidation of a cue-drug memory occurs. However reconsolidation of memory representations formed during Pavlovian conditioning are differentially localized in each site.Through Pavlovian association with the effects of addictive drugs, a conditioned stimulus (CS) acquires both general motivational and sensory-specific conditioned reinforcing properties (Everitt et al. 2000). These associations contribute to the high likelihood of relapse in addicted individuals, yet the extinction of drug CSs by nonreinforced exposure has proved to be of limited therapeutic utility (Conklin and Tiffany 2002). In abstinent humans, drug CSs evoke salient and persistent memories of drug-taking experiences, inducing craving and relapse (Childress et al. 1988; O''Brien et al. 1992), while in animals they also precipitate relapse to, or reinstatement of, drug-seeking behavior (de Wit and Stewart 1981; Meil and See 1996; Fuchs et al. 1998; Weiss 2000). Thus, disrupting drug-related memories might significantly diminish relapse propensity on subsequent exposure to drug-paired CSs, and thereby promote abstinence.Exposure to a drug-associated CS also triggers a process of memory reconsolidation, which restabilizes the reactivated and labile memory (Nader 2003). While reconsolidation may adaptively update memories (Dudai 2006; Hupbach et al. 2007; Rossato et al. 2007; Lee 2009), its disruption may reduce the impact of intrusive or aberrant memories on behavior subsequently (Lee et al. 2005, 2006; Brunet et al. 2008; Kindt et al. 2009; Taubenfeld et al. 2009). The reconsolidation of CS–cocaine memories has been shown to depend upon protein synthesis and expression of the plasticity-associated immediate-early gene, zif268, in the basolateral amygdala (BLA), since zif268 knockdown at memory reactivation disrupted the acquired conditioned reinforcing properties of the CS measured in drug-seeking tasks days or weeks later (Lee et al. 2005, 2006).Although the BLA has an established role in CS-drug memory reconsolidation, it remains unclear whether other sites within limbic cortical-ventral striatal circuitry participate in this process. The nucleus accumbens core (AcbC) is a primary candidate, as zif268 is up-regulated in the AcbC as well as in the BLA following exposure to cocaine CSs (Thomas et al. 2003). Furthermore, the AcbC, which is strongly implicated in Pavlovian influences on drug seeking and relapse (Cardinal et al. 2002; Kalivas and McFarland 2003), has been shown to be a site where the reconsolidation of a drug conditioned place preference (CPP) memory can be disrupted (Miller and Marshall 2005).Given the evidence of increased zif268 expression in the AcbC following CS-drug memory reactivation, we investigated its requirement in the reconsolidation of cocaine-associated memories. To address this issue, we employed two different but complementary paradigms widely used to measure the conditioned effects of CSs associated with drugs of abuse: the acquisition of a new instrumental response with conditioned reinforcement (ANR) and CPP. These procedures have been used successfully to investigate the mechanisms underlying the reconsolidation of appetitive Pavlovian memories, but it is likely that they depend upon different associative mechanisms (Everitt et al. 1991; White and McDonald 1993) that in turn depend upon different neural loci within limbic cortical-striatal circuitry (Cardinal et al. 2002). Therefore, to enable a full comparison with the functional involvement of the BLA, we investigated the necessity for BLA zif268 expression in drug memory reconsolidation as assessed in the CPP paradigm.  相似文献   

20.
We have previously shown that fear extinction is accompanied by an increase of synaptic efficacy in inputs from the ventral hippocampus (vHPC) and mediodorsal thalamus (MD) to the medial prefrontal cortex (mPFC) and that disrupting these changes to mPFC synaptic transmission compromises extinction processes. The aim of this study was to examine whether these extinction-related changes undergo further plasticity as the memory of extinction becomes more remote. Changes in synaptic efficacy in both vHPC-mPFC and MD-mPFC inputs were consequently analyzed when the memory was either 1 d or 7 d old. Increases of synaptic efficacy in the vHPC-mPFC pathway were observed when the memory was 1 d old, but not 7 d after initial extinction. In contrast, potentiation of synaptic efficacy in the MD-mPFC pathway increased over time. In rats that received low-frequency vHPC stimulation immediately after extinction, both vHPC-mPFC and MD-mPFC inputs failed to develop potentiation, and the recall of extinction (both recent and remote memories) was impaired. These findings suggest that post-extinction potentiation in vHPC-mPFC inputs may be necessary for both the recall of recent memory and post-extinction potentiation in the MD-mPFC inputs. This late potentiation process may be required for the recall of remote extinction memory.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号