Protracted neuronal recruitment in the temporal lobes of young children.
Level 5 - mechanism / opinion, no new human data
Bench/laboratory analysis of post-mortem human brain and macaque tissue
PubMed 38122823 · doi:10.1038/s41586-023-06981-x
What was done
The authors analyzed post-mortem human brain tissue across developmental stages and rhesus macaque (Macaca mulatta) brain specimens using immunostaining and single-nucleus RNA sequencing. They profiled germinal zones of the ganglionic eminence, the entorhinal cortex (EC) migratory stream, and the postnatal EC to track neuronal migration and identify the molecular phenotypes of migrating cells.
What was found
A prominent tangential migratory stream of young neurons into the human EC persists until approximately one year of age, with radial dispersal into cortex continuing until two to three years of age. This postnatal migratory stream was absent in rhesus macaques. Molecular profiling showed the migrating cells derive from the caudal ganglionic eminence and mature into LAMP5+ RELN+ inhibitory interneurons. The abstract reports developmental timeframes but does not report exact sample sizes, cell counts, or statistical values.
Why it matters
These findings demonstrate that human entorhinal cortex circuitry undergoes prolonged postnatal cellular recruitment during early childhood, identifying an extended window of plasticity and establishing the developmental origins of interneuron populations vulnerable in Alzheimer's disease.
Limits
The abstract does not report the number of human or non-human primate donors, post-mortem intervals, donor health history, or quantitative cell counts. Cross-sectional post-mortem histology cannot directly measure dynamic migration in vivo.