Mountains of research: Where and whom high-altitude physiology has overlooked

High altitude is a natural setting in which to study human acclimatization and adaptation. Here, I identify where and in whom high-altitude physiology research has occurred. There has been a mismatch between countries with large high-altitude populations vs. where high-altitude research has been conducted. From 1970 to 2020, 83% of high-altitude physiology research took place in just seven countries: Nepal, China, USA, Peru, India, Bolivia and Italy. Collectively, these countries account for only 35% of the global population living above 2500 m. Furthermore, high-altitude physiology research has predominantly studied low-altitude residents visiting high altitude and female participants are under-represented. Accordingly, the included populations are not necessarily a proportional representation of high-altitude residents. Here, I discuss how this influences our understanding of high-altitude adaptation. Finally, I highlight past initiatives to increase diversity in high-altitude research. By identifying the broad gaps in high-altitude physiology research, I propose exciting, inclusive opportunities to study human high-altitude physiology.

How does V1 population activity inform perceptual certainty?

Neural population activity in sensory cortex informs our perceptual interpretation of the environment. Oftentimes, this population activity will support multiple alternative interpretations. The larger the spread of probability over different alternatives, the more uncertain the selected perceptual interpretation. We test the hypothesis that the reliability of perceptual interpretations can be revealed through simple transformations of sensory population activity. We recorded V1 population activity in fixating macaques while presenting oriented stimuli under different levels of nuisance variability and signal strength. We developed a decoding procedure to infer from V1 activity the most likely stimulus orientation as well as the certainty of this estimate. Our analysis shows that response magnitude, response dispersion, and variability in response gain all offer useful proxies for orientation certainty. Of these three metrics, the last one has the strongest association with the decoder's uncertainty estimates. These results clarify that the nature of neural population activity in sensory cortex provides downstream circuits with multiple options to assess the reliability of perceptual interpretations.

At-home dried blood spot (DBS) collection to increase population heterogeneity representation in pediatric research: An ECHO study

Self-collection of dried blood samples (DBS) in the participant's home provides an alternative to university/hospital visits for research and has the potential to improve the representation of population heterogeneity in research. This study aimed to assess the feasibility of guardian and/or self-DBS collection in healthy youth in the lab and home. Guardians/youth [N = 140; females = 63; M _age = 8.73, SD _age = 3.56] who enrolled in a longitudinal study of typical development were asked during a lab visit to provide a DBS. Upon providing a sample, the participants were asked if they would be willing to self-collect in the home and return the sample via the post office. Of those asked to provide a sample in the lab, 82% consented and 18% declined, with a significant difference in age but no significant difference in sex, ethnicity, race, or family income. Of those who provided a sample in the lab, 75% were willing to self-collect DBS in the home, with no significant difference in demographic variables between them. We report a quality assessment and DNA extraction results from a subset of samples. The results demonstrate a high feasibility of DBS collection from healthy youth for research purposes both in the laboratory and in the home across different demographic variables. Developmental researchers should consider including this approach in their studies to increase population heterogeneity representation.

Participant diversity is necessary to advance brain aging research

An absence of population-representative participant samples has limited research in healthy brain aging. We highlight examples of what can be gained by enrolling more diverse participant cohorts, and propose recommendations for specific reforms, both in terms of how researchers accomplish this goal and how institutions support and benchmark these efforts.