title: Development of afferent lamination in the fascia dentata of the rat.
abstract: In the present study we examine the development of afferent lamination in the fascia dentata of the postnatal rat, as a first step in determining possible mechanisms controlling synaptic specificity in this system. This analysis is based on degeneration-induced argyrophilia as well as autoradiographic labeling of the entorhinal and commissural/associational afferents. Both methods show that in spite of the immaturity of the neonatal fascia dentata, these afferent systems have already established territorial relationships by 4 days of age which persist into adulthood. At 4 days, the entorhinal projection is restricted approximately to the outer 45 mum of the 80 mum wide molecular layer. The commissural/associational projection occupies appoximately the inner 35 mum of the molecular layer. At older ages the commissural/associational zone increases in width very slowly relative to the entorhinal zone. We also discuss these results in relation to potential mechanisms of afferent development and dendritic differentiation.
mesh_terms: D000344:Afferent Pathways / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D000367:Age Factors; D000818:Animals; D006624:Hippocampus / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D009474:Neurons / Q000502:physiology; D051381:Rats