Protracted Neuronal Recruitment in the Temporal Lobe of Young Children

This study describes a stream of migrating neurons directed to the human entorhinal cortex. This migration is among the most protracted in the developing human brain, with young neurons still arriving at 2-3 years of age. We did not observe a similar migratory process in the early postnatal macaque brain, which suggests that this migration may be uniquely delayed or extended into early postnatal human life. Using immunohistochemistry and single‐cell RNA sequencing (scRNA‐seq), we identified these late-arriving neurons as being mainly CGE-derived LAMP5+/RELN+ interneurons. ]]> Postmortem human brain samples with unknown neuropathological condition were included and collected from University of California, San Francisco (UCSF) and University of Maryland through the NIH Neurobiobank. The samples obtained through the Neurobiobank were selectively to contain the entorhinal cortex, and the preference was given to samples with the highest RNA quality, as assessed by their RNA integrity number (RIN) scores. The RNA quality was assessed in the laboratory before sequencing, and the samples with RIN scores < 7 were excluded from the study. ]]>