Extensive migration of young neurons into the infant human frontal lobe

Building the human brain As the brain develops, neurons migrate from zones of proliferation to their final locations, where they begin to build circuits. Paredes et al. have discovered that shortly after birth, a group of neurons that proliferates near the ventricles migrates in chains alongside circulatory vessels into the frontal lobes (see the Perspective by McKenzie and Fishell). Young neurons that migrate postnatally into the anterior cingulate cortex then develop features of inhibitory interneurons. The number of migratory cells decreases over the first 7 months of life, and by 2 years of age, migratory cells are not evident. Any damage during migration, such as hypoxia, may affect th…

Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.

New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus(1-5). This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease(6-10). In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day(11), whereas other studies find many fewer putative new neurons(12-14). Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal …

Does Adult Neurogenesis Persist in the Human Hippocampus?

Rapid Reform and Unfinished Business: the development of education in independent Latvia 1991-2007

Education in Latvia has changed a great deal in the last 15 years. The development of an independent and democratic state system has creatively combined elements of foreign experience and influence with the enrichment and further development of features of the earlier Latvian system. This article outlines the main steps in this process of change and then goes on to argue that there is still much to be done: firstly, to consolidate and secure the developments to date, and secondly, to enable a successful functioning within the EU in a rapidly changing wider context.