3 - The human brain and longitudinal research in human development

Summary

INTRODUCTION

Knowledge in the field of human developmental neurobiology has grown considerably during recent years. This chapter will selectively review only data and concepts which I consider to be helpful in designing longitudinal research in human development.

Human brain growth can be described as the increase in weight and volume of the brain in pre-natal and post-natal life. A first idea about the magnitude and speed of human brain growth can be obtained by looking at the changes in the shape of the human brain and the complexity of the gyri on its surface during the latter part of gestation (Cowan, 1979). The fetus in the womb shows a growth spurt of the brain, but this can also happen post-natally when a child is born prematurely. Pre-natal growth can be studied by ultrasound measurement of the biparietal diameter of the head. Post-natal growth can be assessed by measuring head circumference. The values obtained should be placed on growth charts and should be compared with the changes in body weight and height over the same period.

A longitudinal study on biological risk factors, and its relation with later psychosocial development is of little value without anthropometric data. One could even argue that each longitudinal study should include a minimum of biological growth variables to explain some of the age-related variations in the non-biological variables.