Standardized adult dentate-neuron surviving additions exceed 0.1% in one year.

In adults without diagnosed neurological disease, the age-standardized mean one-year surviving addition fraction of dentate-gyrus granule neurons exceeds 0.001. At exact age a, define r(a)=N_new(a,a+1)/N_total(a): N_new counts cells whose final mitosis occurs during [a,a+1) Julian years of age and which are alive and differentiated as mature dentate granule neurons at a+1; N_total counts ALL mature dentate granule neurons in both hippocampi at a, including nonrenewing neurons. Births that die before the endpoint, progenitor proliferation, DNA repair and prenatal cells maturing late do not enter the numerator. The target is the arithmetic mean of r(a), not a median or a renewing-subpopulation turnover rate, standardized uniformly over 25 <= a < 65 and equally across female and male biological-sex strata. Within each age/sex stratum, the reference population is neurologically healthy US residents with the remaining demographic distribution of the 2020 US census. This reference distribution, age range, one-year endpoint and threshold are contract conventions, not a universal human rate.

YES: Each independent birth-dating or validated-lineage study estimates this same standardized mean and places its 95% interval wholly above 0.001, with mature granule-neuron identity, survival to the one-year endpoint, the all-neuron denominator and age/sex/demographic standardization identified. Require >= 20 independent donors with age coverage throughout the domain, controls for DNA repair/contamination/tissue processing, and uncertainty propagated from birth-death and population-transport models. Cross-sectional carbon dating is eligible only if the specified one-year surviving-addition estimand is identifiable and robust to supported birth-death models. NO: Each otherwise eligible independent study places the 95% upper bound for that same standardized mean <= 0.001. Unidentified one-year survival, unsupported transport to the reference population, an interval crossing 0.001, immature-neuron markers alone, or a rate within only a renewing subpopulation leaves this contract UNDECIDED. Reference sources: Spalding et al.: dynamics of hippocampal neurogenesis (https://doi.org/10.1016/j.cell.2013.05.002); 2020 US census reference population (https://www.census.gov/programs-surveys/decennial-census/decade/2020.html); Adult human proliferating neural progenitors (https://www.science.org/doi/10.1126/science.adu9575); Human hippocampal neurogenesis in ageing (https://www.nature.com/articles/s41586-026-10169-4). Evidence policy: use public primary research with methods and uncertainty, plus the named reference sources below. A preprint can inform the estimate but cannot alone meet a terminal criterion; require a peer-reviewed primary result and an independent reproduction using non-overlapping observations or independently prepared samples, unless this is a mathematical proof or the specific criterion instead requires independently implemented calculations. Report data provenance, exclusions, calibration, statistical model and systematic uncertainty. Independence means different data acquisition, not two papers reanalysing the same sample. For a quantitative terminal test, both independent results must meet the stated threshold; disagreement or an interval crossing the boundary means UNDECIDED. Use the final corrected version public at the signed round's evidence cutoff (UTC); exclude later evidence until a later eligible round. Every report in a terminal round must use the same cutoff, covered by the verified signed context and enforced by the configured terminal protocol; a different cutoff requires a new eligible round, never reinterpretation of a signed report or mutation of an immutable binding. This market has no calendar expiry. Retracted findings cannot supply a terminal result. If a named source disappears, use its DOI/publisher or an archived identical version, then an equivalent primary publication applying these unchanged definitions; if none is accessible, remain UNDECIDED, never substitute a different test. Missing data, failed replication, a null search outside the specified domain, or an untested alternative is not automatically NO. These are instructions for evidence assessment, not an automatic truth oracle: scientific interpretation and systematic-error judgment remain. Settlement follows the configured platform mode: terminal mode requires one valid round with all three frozen models returning the same explicit YES or NO and criterion_met=true; any UNDECIDED, failure or disagreement leaves it unresolved. Legacy proposal/challenge mode requires its recorded review process. Model agreement does not prove scientific truth. Invalidity is not NO and this text does not authorize a refund or cancellation: only a cancellation rule disclosed before exposure, if the configured contract supports it, can apply. Otherwise pause new entries and preserve holders' existing rights. Never reinterpret terms after listing.