engleski

The role of the subplate zone in the structural plasticity of the developing human cerebral cortex.

Background: Perinatal lesions of the human brain are followed by a variable extent of functional plasticity and recovery of neurological and cognitive functions. In trying to determine the structural basis of that plasticity, previous studies proposed an essential role for the neuronal elements of the subplate zone. Aim: The purpose of this review is to identify essential features of the subplate zone which represent a developmental potential significant for the areal, axonal, modular and synaptic plasticity of the cerebral cortex, with special emphasis on long "waiting" axonal pathways of the subplate zone. Results: The following features of the subplate zone were found to be essential for its role in the structural plasticity of the human cerebral cortex after periventricular lesions: (1) the presence of waiting fibres ; (2) early areal accumulation of thalamocortical afferents ; (3) early tangential compartmentalization of neuronal elements ; (4) the abundance of extracellular matrix and growth-promoting molecules ; (5) the presence of early maturing neurons, neurotransmitters and synapses ; (6) differential cell death, and (7) a specific response to hypoxia or perfusion failure. The crucial period for the participation of thalamocortical afferents in the areal and laminar reconstruction is around 24/26 postovulatory weeks (W). For corticocortical callosal and long associative pathways, the critical period is around 34 W and lesions of these fibres can probably cause changes in the formation of gyri, especially around ventriculomegalic and porencephalic regions. It is essential that the subplate zone as well as major related axonal bundles can be visualized in the human cerebrum by the MRI technique. Conclusions: "Waiting" fibres and transient cells of the subplate zone participate in areal, laminar, gyral, axonal, modular and synaptic rearrangements after perinatal lesion in the preterm infant and set limits for the structural plasticity between 22 and 34 W.

extracellular matrix; cortical afferents; transient fetal cells; transient synapses

nije evidentirano