Cajal-Retzius cells: organizers of cortical development

Abstract

Cajal-Retzius cells (CRc) are a major neuronal population in the marginal zones of the developing neocortex and hippocampus. CRc belong to the earliest born neurons in the cortex and originate from several regions at the pallial-subpallial border. A substantial fraction of CRc disappears during postnatal development. CRc express a variety of neurotransmitter receptors, receive mainly GABAergic synaptic inputs and give rise to glutamatergic synapses. Recent studies identified some modes of how CRc are integrated into immature neuronal circuits, although their exact role for immature information processing remains unknown. As a major source for the extracellular matrix protein reelin, which is critically involved in lamination of the cerebral cortex, CRc are an important factor for the structural development of the neocortex and hippocampus. In addition, CRc contribute to the patterning of cortical areas and shape the development of perforant path connections in the hippocampus. In summary, CRc are a major cellular element in the structural development of the cerebral cortex and may serve as a link between early electrical activity and morphological organization during prenatal und early postnatal development.