Normal and Abnormal Development of the Human Cerebral Cortex

The functional organization of the developing human brain does not only differ substantially from that of the mature brain, but it also undergoes continuous changes. During fetal brain development, transient neuronal circuitries are formed which are essential for the subsequent development of mature projections. Transitory connections are linked to transient structures which are particularly prominent in the human fetal brain and are susceptible to damage under pathological circumstances. The First International Symposium on Normal and Abnormal Development of the Human Fetal Brain aimed to gather basic information on these transitory organizations and the major developmental events that occur in the fetal brain. This paper summarizes a roundtable discussion at the symposium on transient characteristics and injuries in the developing human cerebral cortex. An overview of cortical development is first presented and then the development of several fetal structures, including the subventricular zone, ganglionic eminence, marginal zone, subplate and cortical plate, is discussed with regard to their important contribution to the formation of the correct fiber projections in the adult. The last section focuses on the anomalies that are commonly found in the premature fetal brain on the one hand and on the other hand are related to the transitory characteristics of the developing brain.