Development of the Primate Visual System Throughout Life

Abstract

Developmental principles derived from experimental analysis of the visual system in nonhuman primates provide insight into the normal and pathological development of vision in man, and reveal some general mechanisms of brain maturation and aging. This overview is based on a series of longitudinal studies in the developing rhesus monkey carried out in my laboratory over the last two decades. This type of work poses extraordinary challenges, as there is no easy and straightforward way to determine how functional circuitry is formed and maintained in a species with a lifespan of more than 30 years. To be meaningful, the research has to be carried out on the entire visual system, rather than focused on its components, and the analysis has to be rigorously quantitative, as many changes may be relatively small. The introduction of computer-aided quantitative methods, and the availability of cell class-specific markers, neurotransmitters and receptors have opened unprecedented opportunities for probing the principles governing the development of functionally dedicated networks even in the large and complex primate brain. I will also include in my presentation our data on the development of binocular as well as color-opponent or broad-band parallel pathways from the retina across the lateral geniculate nucleus to the striate cortex, the formation of cytoarchitectonic maps, as well as the dynamics of synaptic connections and their biochemical maturation in the visual system. Although progress in this field has been possible due to research carried on in many laboratories, this short overview is based exclusively on the studies done in my laboratory. Description of the material and methods, experimental details, factual data and additional relevant literature can be found in the papers listed in the bibliography.