INSIGHT of Medicine(phase 16, 2024)

1.The impact of adult neurogenesis on affective functions: of mice and men

DOI: 10.1038/s41380-024-02504-w

https://www.nature.com/articles/s41380-024-02504-w

This review focuses on the influence of newly-generated neurons in the brain on affective functions. While adult neurogenesis, the production of new neurons in the adult brain, has been established in mammals, there has been reluctance to translate this concept to humans. However, recent data suggests that new neurons can be derived from both stem cells and a population of neuroblasts that mature and become integrated into adult brain circuits under specific signals. The review also discusses the significance of recruiting new neurons in adult brain circuits, particularly in the context of affective outcomes. It emphasizes that adult neurogenesis may be the crucial cellular process that integrates internal and external environmental elements to regulate brain functions. While caution is necessary regarding unrealistic promises, exploring the potential of neural recruitment in adult primates, including humans, is important.

2.Population-wide cerebellar growth models of children and adolescents

DOI: 10.1038/s41467-024-46398-2

https://www.nature.com/articles/s41467-024-46398-2

This study focuses on the role of the cerebellum in cognitive functions and neurodevelopment, going beyond its traditionally known involvement in motor function. Using a large dataset of neuroimaging scans from individuals aged 6-17 years, the researchers provide detailed models of cerebellar development during childhood and adolescence. They offer openly accessible models based on both anatomical and functional parcellation of the cerebellum. The findings reveal an anterior-posterior growth gradient in the cerebellum, similar to maturation patterns observed in the cerebral cortex. This suggests a direct relationship between cerebellar and cortical development. Furthermore, the researchers demonstrate how this approach can be used to identify cerebellar abnormalities in clinical samples. These findings enhance our understanding of the cerebellum's role in cognitive development and provide insights into potential clinical applications.

3.Biomimetic versus arbitrary motor control strategies for bionic hand skill learning

DOI: 10.1038/s41562-023-01811-6

https://www.nature.com/articles/s41562-023-01811-6

Researchers aimed to determine whether biomimetic motor control, resembling natural hand movements, provides superior outcomes compared to non-biomimetic control for bionic limbs. Two groups of non-disabled participants learned to control a wearable myoelectric bionic hand using different strategies. The biomimetic group mimicked the desired bionic hand gesture with their biological hand, while the arbitrary control group mapped an unrelated biological hand gesture to the desired bionic gesture. Both groups showed improved bionic limb control, reduced cognitive reliance, and increased embodiment over time. Biomimetic users demonstrated more intuitive and rapid control early in training, while arbitrary users matched biomimetic performance later and showed enhanced generalization to new control strategies. The findings suggest that the optimal control strategy lies within the biomimetic-to-arbitrary spectrum, depending on individual users, training opportunities, and requirements.

4.States of epistemic curiosity interfere with memory for incidental scholastic facts

DOI: 10.1038/s41539-024-00234-w

https://www.nature.com/articles/s41539-024-00234-w

High levels of curiosity can enhance learning and memory for new information. However, a study found that when individuals experienced a high state of curiosity prompted by a trivia question, their memory for unrelated scholastic facts presented around the same time was actually impaired. The study involved participants being shown trivia questions followed closely by scholastic facts unrelated to the trivia. Memory performance for the scholastic facts was lower when they were presented after high-curiosity trivia questions compared to low-curiosity ones. These findings challenge previous research indicating that curiosity improves memory for incidental stimuli. It suggests that when individuals are highly curious about specific information, their ability to encode and retain unrelated and complex scholastic facts presented in close temporal proximity may be hindered.

5.Dnmt3a1 regulates hippocampus-dependent memory via the downstream target Nrp1

DOI: 10.1038/s41386-024-01843-0

https://www.nature.com/articles/s41386-024-01843-0

The study focused on the role of DNA methylation, specifically the function of DNA methyltransferases (Dnmts), in long-term memory formation. It aimed to determine whether individual Dnmts have unique or redundant roles in memory formation and to explore the downstream processes controlled by Dnmts during memory consolidation. The research found that Dnmt3a1, a predominant Dnmt in the adult brain, is necessary for long-term spatial object recognition and contextual fear memory. Through RNA sequencing, the study identified a genomic program regulated by Dnmt3a1, involving genes associated with functional and structural plasticity. Among these genes, Neuropilin 1 (Nrp1) was identified as a downstream target of Dnmt3a1, essential for hippocampus-dependent memory formation. The findings revealed a specific mechanism involving Dnmt3a1 and Nrp1 in memory formation, emphasizing the role of distinct epigenetic regulators in brain function.