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Introduction: Long‐term spaceflight composite stress (LSCS) can cause adverse effects on human systems, including the central nervous system, which could trigger anxiety and depression. Aims: This study aimed to identify changes in hippocampus synaptic plasticity under LSCS. Methods: The present study simulated the real long‐term space station environment by conducting a 42‐day experiment that involved simulating microgravity, isolation, noise, circadian rhythm disruptions, and low pressure. The mood and behavior of the rats were assessed by behavior test. Transmission electron microscopy and patch‐clamp were used to detect the changes in synapse morphology and electrophysiology, and finally, the expression of NMDA receptor channel proteins was detected by western blotting. Results: The results showed that significant weight loss, anxiety, and depressive behaviors in rats were observed after being exposed to LSCS environment for 42 days. The synaptic structure was severely damaged, manifested as an obvious decrease in postsynaptic density thickness and synaptic interface curvature (p < 0.05; p < 0.05, respectively). Meanwhile, LTP was significantly impaired (p < 0.0001), and currents in the NMDAR channel were also significantly reduced (p < 0.0001). Further analysis found that LSCS decreased the expression of two key subtype proteins on this channel. Conclusion: These results suggested that LSCS‐induced depressive behaviors by impairing synaptic plasticity in rat hippocampus. [ABSTRACT FROM AUTHOR]

This commentary examines the synergy between meta-learned models of cognition and integrative learning in enhancing animal and human learning outcomes. It highlights three integrative learning modes - holistic integration of parts, top-down reasoning, and generalization with in-depth analysis - and their alignment with meta-learned models of cognition. This convergence promises significant advances in educational practices, artificial intelligence, and cognitive neuroscience, offering a novel perspective on learning and cognition.

Background: We had previously advanced the concept of "Integrative Learning", that is, "under the role of 'meta-learning self', learners actively integrate learning materials to achieve rapid and in-depth understanding of knowledge", and designed an animal behavioral model to compare the effects of "Integrative Learning" (IL) vs . "Progressive Learning" (PL) in young rats. It was found that IL is more advantageous than PL. Here, we aim to examine whether the same phenomenon persist in older rats., Methods: Fifteen 12-month-old male Sprague-Dawley (SD) rats were selected as subjects and randomly divided into the IL group and the PL group, and a 14-unit integrative T-maze was constructed for the study. Training and testing procedures contained three stages: the learning stage, the memory retention test stage and the Gestalt transfer learning stage. Data on young rats (1-month-old) from the previous study were also drawn here for comparisons on learning performance., Results: (1) The 12-session learning stage can be divided into three sub-stages as each sub-stage represented the new opening of one third of the whole path in the PL group. There were significant interactions in total errors made between groups and sessions: the PL group had significantly fewer errors during Sub-stage One due to a much shorter path to be learned, however, the IL group's errors made sharply dropped as learning progressed into Sub-stage Two and Three, and were maintained at a significantly lower level than the PL group during Sub-stage Three. (2) When compared with young rats, age had a main effect on the number of errors made-the 1-month-old groups learned overall better and faster than the older groups, whereas the pattern of group differences between the IL and PL learning modes remained consistent across young and older groups. (3) Unlike young rats, during the memory retention test stage and the Gestalt transfer learning stage, the IL group did not perform better than the PL group in older rats., Conclusions: (1) "Integrative Learning" promotes learning but not memory in older rats. (2) Higher-order cognitive abilities that support meta-cognition, long-term retention and knowledge transfer might be deteriorating in older rats., Competing Interests: The authors declare that they have no competing interests., (© 2023 Yin et al.)