RESUMO
Diversity in brain health is influenced by individual differences in demographics and cognition. However, most studies on brain health and diseases have typically controlled for these factors rather than explored their potential to predict brain signals. Here, we assessed the role of individual differences in demographics (age, sex, and education; n = 1298) and cognition (n = 725) as predictors of different metrics usually used in case-control studies. These included power spectrum and aperiodic (1/f slope, knee, offset) metrics, as well as complexity (fractal dimension estimation, permutation entropy, Wiener entropy, spectral structure variability) and connectivity (graph-theoretic mutual information, conditional mutual information, organizational information) from the source space resting-state EEG activity in a diverse sample from the global south and north populations. Brain-phenotype models were computed using EEG metrics reflecting local activity (power spectrum and aperiodic components) and brain dynamics and interactions (complexity and graph-theoretic measures). Electrophysiological brain dynamics were modulated by individual differences despite the varied methods of data acquisition and assessments across multiple centers, indicating that results were unlikely to be accounted for by methodological discrepancies. Variations in brain signals were mainly influenced by age and cognition, while education and sex exhibited less importance. Power spectrum activity and graph-theoretic measures were the most sensitive in capturing individual differences. Older age, poorer cognition, and being male were associated with reduced alpha power, whereas older age and less education were associated with reduced network integration and segregation. Findings suggest that basic individual differences impact core metrics of brain function that are used in standard case-control studies. Considering individual variability and diversity in global settings would contribute to a more tailored understanding of brain function.
Assuntos
Encéfalo , Cognição , Eletroencefalografia , Humanos , Masculino , Feminino , Adulto , Cognição/fisiologia , Pessoa de Meia-Idade , Encéfalo/fisiologia , Idoso , Adulto Jovem , Individualidade , Adolescente , Fatores Etários , Envelhecimento/fisiologiaRESUMO
AIM: This study aimed to evaluate the expression levels of miR-99b and miR-135b in peritoneal carcinoma and liver metastases associated with Colorectal Cancer (CRC), assess their association with the intracellular signaling pathway proteins Kirsten Rat Sarcoma Virus (KRAS) and Akt, and investigate their effects on survival. MATERIALS AND METHODS: Changes in the KRAS gene and Akt proteins, expression levels of miR-99b and miR-135b, and factors affecting survival were compared between colorectal cancer-associated peritoneal carcinomatosis and liver metastasis. RESULTS: The expression levels of miR-99b and miR-135b and the immunohistochemical grade classification score of Akt were higher in colorectal cancer, peritoneal carcinomatosis, and liver metastasis than in normal tissues (p < 0.05). MiR-99b expression was highest in CRC, whereas miR-135b expression was highest in peritoneal carcinomatosis (p < 0.05). The expression level of miR-99b decreased and that of miR-135b increased in peritoneal and liver metastases compared with that in the tumor tissue. MiR-99b, Akt, and recurrence were risk factors that affected the overall survival rate in the model of clinical predictions (p = 0.045, p = 0.006, and p = 0.012, respectively). CONCLUSION: While the expression of miR-99b was highest in the primary tumor, its decrease in liver metastasis and peritoneal carcinomatosis suggests that miR-99b has a protective effect against liver metastasis and peritoneal carcinomatosis. However, the detection of miR-135b expression was highest in peritoneal carcinomatosis and liver metastasis compared with that in the colorectal cancer tissues suggesting that it facilitates peritoneal carcinomatosis and liver metastasis. Furthermore, miR-99b, KRAS mutations, and Akt are risk factors for the overall survival of colorectal cancer.