Ectopic recruitment of neuroblasts in striatal myelin bundles and nucleus accumbens following AraC chemical lesion

: In the adult brain, neural stem cells (NSCs) constitutively generate new neurons in specific neurogenic domains. Recent research has unveiled reactive neurogenesis, whereby brain injury triggers NSC activation, enhancing their differentiation potential and guiding progeny to injured areas. Our study provides evidence of alternative migration pathways for newborn neurons in the mouse subcortical forebrain, revealed by administration of a chemotherapeutic agent. This allows a high number of newborn neurons to migrate long distances over an extended period. Notably, a subpopulation of neuroblasts diverts from the canonical SVZ-olfactory bulb (OB) rostral migratory stream toward the striatum (STR), with distinct localization along striatal myelin tracts and through nucleus accumbens (NAc) to the anterior commissure (AC). This neuroblast (NB) rerouting is accompanied by with oligodendrocyte lineage dysregulation and myelin deficits, suggesting a link between ectopic NB presence and observed myelin abnormalities.