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Behavioral flexibility is an indispensable cognitive ability that allows the adjustment of behavioral responses to different situations, while resilience refers to the capability to deal effectively with stress. On one hand, standard laboratory housing provides impoverished cognitive, sensory, and physical stimulation compared to the conditions found in nature. Conversely, enriched and naturalistic housing conditions offer a broadening in the behavioral repertoire that can be depicted by the animals in their home cages, in addition to enabling a better management of possible stressors. Here, we investigated the effects of environmental enrichment and naturalistic housing compared to the standard laboratory housing on different behavioral tasks, including Morris water maze, open field, object location, and fear conditioning. This allowed us to evaluate how different housing conditions modulate behavioral flexibility and resilience to stress, in addition to spatial memory, in adult male rats. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
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Anxiety is highly common, and stress is a major trigger for anxiety. Anxiety includes heightened threat assessment and avoidance, but we do not fully understand which components are sensitive to stress. Rodents show a balance of exploration and avoidance that incorporates threat assessment prior to making the relatively risky decision to explore an open area. The purpose of this study was to determine if stress impacts risk assessment and if this is tied to the effects of stress on exploration. The present study used elevated plus maze (EPM) to test the effects of repeated social defeat stress (RSDS) on risk assessment behaviors in adult male rats. We then tested the effects of diazepam, an anxiolytic that reduces the impact of stress on EPM exploration, to further clarify the relationship between risk assessment and risky behavior in the EPM. We found that RSDS decreased time in the open arm, similar to prior studies. We also found that RSDS increased the likelihood of the primary risk assessment behavior, stretch and attend posture (SAP), increased SAP prior to entering an open arm, and decreased the likelihood that a rat would enter an open arm after SAP. Diazepam ameliorated the effects of RSDS on both SAP and exploratory behavior, further linking risk assessment and subsequent exploratory behaviors. These results suggest that increased risk assessment and reduced risky choices after risk assessment are tied to effects of stress on exploration and provide novel insight into how stress may increase avoidance by effects on risk assessment. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
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Consolidated long-term memories can be modified when destabilized at reactivation (RA). This must be followed by an upregulation of protein synthesis to return the memory to a stable state. Reconsolidation is suggested to maintain the relevance of stored memories, preserving behavioral flexibility. Older or strongly encoded memories resist reconsolidation because of biological boundary conditions and destabilization of such memories is more likely in the presence of prediction error at reactivation. The neurotransmitter dopamine (DA), which has been implicated in prediction error, has been linked to destabilization using appetitive or aversive memory paradigms. However, more neutral memories also undergo modification to adapt to changing environments. Evidence suggests that a salient novel cue presented at reactivation can trigger destabilization of boundary condition-protected object memories, but DA has not yet been implicated in this process. Using male rats in a modified spontaneous object recognition task, we report that systemic administration of the D1 receptor (D1R) antagonist SCH23390 blocked recently encoded and novelty-induced relatively remote object memory destabilization. Further, systemic administration of the D1R agonist SKF38393 promoted destabilization of relatively remote memory traces in the absence of salient novelty at reactivation. Finally, systemic D1R antagonism and agonism blocked and promoted integrative memory updating, respectively, in the postreactivation object memory modification task. This work therefore advances current knowledge related to the role of DA in the dynamic nature of memory storage. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
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The posterior parietal cortex (PPC) is an associative neocortical region that integrates multiple streams of information and is implicated in spatial cognition and decision making. In some cases, however, the PPC is not required for these functions. One possibility is that the PPC is recruited when spatial complexity is high. Yet, few studies of PPC function have explicitly manipulated environmental complexity, complexity of spatial changes, or the temporal structure of spatial tasks. To examine whether task complexity recruits PPC function, we tested rats with neurotoxic damage to the dorsal PPC on a series of tasks varying in spatial and temporal complexity. Recognition memory was first assessed in standard exploration tasks, including object recognition, object location, and object in place, as well as a more complex object task in which spatial changes occurred across multiple delays. Spatial navigation was assessed in the circular hole board maze (Barnes maze), and temporal processing was assessed in a temporal order task. PPC damage spared performance on standard recognition memory tasks but caused deficits on tasks involving changes in object configuration or multiple changes across time. PPC damage spared acquisition on the Barnes maze but impaired retention and decreased efficiency of search strategies. PPC damage did not impact temporal order memory. Overall, these results suggest that the PPC is necessary when spatial complexity of the task increases attentional and long-term memory demands. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
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At the core of adaptive behavior is the ability to accurately predict relationships between environmental events. Such predictions require associative relationships to be updated in the face of changing contingencies. One example of such updating is the overexpectation effect. Prior investigations into overexpectation in the appetitive domain revealed that female rats require additional training to manifest the effect compared to males. This finding raises two possibilities, namely, that females are also slower at updating (reducing) fear expectancies in overexpectation, reflecting a general learning trait across valence domains, or, conversely, that they are comparable or perhaps even faster at reducing fear expectancies compared to males. To test these hypotheses, we trained male and female rats in aversive overexpectation. Our results show that while males show the overexpectation effect following two trials of overexpectation training, females are less likely to do so given the same parameters. Increasing the number of overexpectation training trials from two to four yielded a successful overexpectation effect in females. These results align with prior research in the appetitive domain (Lay, Frate, et al., 2020), providing evidence that females require more trials to downregulate previously acquired associations, whether the outcome is appetitive or aversive. These data carry important implications for the behavioral, neural, and hormonal mechanisms that support reduction in conditioned responding in both sexes and may shed light on sex differences reported in anxiety-related disorders. (PsycInfo Database Record (c) 2025 APA, all rights reserved)
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Thu, 18 Apr 2024 00:00:00 GMT