Why do children and adults believe others apologize?

Neurological diseases and neuroinflammation, including Parkinson’s disease (PD), Alzheimer’s disease (AD) (Cheng et al., 2025; Martinez and Peplow, 2025), and migraine, are major causes of death and poor health worldwide (Samanta et al., 2024; Shi and Yong 2025). Current treatments for the nervous system generally include drug therapy, namely, neurotransmitter modulators (such as levodopa, paroxetine, and olanzapine; Dean and Standaert 2024; Zheng et al., 2024), central nervous system (CNS) stimulants/depressants (such as methylphenidate) (Shellenberg et al., 2020), neuroprotective agents/anti-inflammatory drugs (such as edaravone; Singh et al., 2024), surgical treatment, immunotherapy and targeted therapy, psychological therapy, and behavioural interventions (Lopes et al., 2022). However, these treatments have considerable drawbacks. Drug therapy is prone to side effects, surgical treatment is highly traumatic, and immunotherapy and targeted therapy carry the risk of long-term immunosuppression. Psychotherapy has limited effectiveness (García-González et al., 2024). Finding the right treatment method has become a tricky problem. In recent years, an increasing number of studies have shown that the gut microbiota, an important regulator, can achieve two-way signal regulation with the central nervous system through the gut–brain axis (Park et al., 2025; You et al., 2025), thereby slowing damage to and repairing the nervous system (Góralczyk-Bińkowska et al., 2022). The use of the gut microbiota for therapeutic purposes is a novel and emerging area of research, with certain specific gut bacterial strains currently serving as the focal point of ongoing studies. The brain–gut axis is an intermediate regulator connecting the gastrointestinal tract and the central nervous system (Lee et al., 2023; Ju et al., 2025; Sun et al., 2025). It has bidirectional conduction and complex characteristics (Kraimi et al., 2024), including multiple components such as the vagus nerve, enteric nervous system, and endocrine pathways (Naufel et al., 2023). Specifically, the gut microbiota secretes metabolic products such as short-chain fatty acids (SCFAs), neurotransmitters, inflammatory factors, and other signaling molecules, which ultimately regulate the levels of inflammatory factors, neurotransmitter balance, metabolic balance, blood–brain barrier stability, and immunity in the central nervous system (Fan and Pedersen, 2021; Dicks, 2022). Recent studies have shown that the brain–gut axis plays a key regulatory role in emotions, cognition (Toader et al., 2024), and neural regeneration (Merlo et al., 2024). Therefore, identifying specific gut bacterial strains that can alleviate neurological diseases through the important medium of the gut–brain axis has become a key issue that needs to be addressed. (AKK) is an oval, nonmotile, strictly anaerobic, gram-negative bacterium first isolated from human feces in 2004 (Zhou and Zhang, 2019; Rodrigues et al., 2022; ). AKK resides within the mucus layer of the human intestinal tract and uses mucin secreted by intestinal epithelial cells as its main carbon source. By degrading mucin, AKK produces SCFAs, which are essential for intestinal health because they regulate the acid-base balance in the gut (Kim et al., 2022). AKK can briefly colonize the mucous layer of the intestine, and the reason for this short-term colonization may be that AKK possesses various genes and proteins related to mucin and surface adhesion, which may support short-term biofilm formation and the attachment of AKK to the mucosal surface (Mulhall et al., 2020; Trastoy et al., 2020). These structures can help AKK adhere to and enhance the integrity of the intestinal barrier, but whether they can form a lasting biofilm still requires further research. Additionally, AKK is unable to form spores, and thus its survival relies on the ability to use resources from the external environment rather than being able to colonize based on its own favorable resources (Zeng et al., 2025). Finally, we speculate that AKK may have a metabolically complementary relationship with other gut microbiota, and that the monosaccharides released after its degradation of mucin can be used by other bacteria. Although AKK comprises only approximately 3% of the intestinal microbiota, it plays a critical role in maintaining the intestinal barrier (Liu et al., 2022). It increases the thickness of the mucus layer and improves barrier function, preventing pathogenic microorganisms from crossing the intestinal epithelium (Geerlings et al., 2021). AKK has significant anti-inflammatory effects, especially in diseases associated with intestinal inflammation, such as inflammatory bowel disease (Hasani et al., 2021). Changes in AKK abundance affect gut health, with reduced levels linked to metabolic diseases, including obesity and diabetes, as well as chronic inflammation (Mo et al., 2024). Recent studies have focused on the association between AKK abundance and