Early Learning Capability in Rodents: A Review (Rattus Norvegicus and Mus Musculus)

Available data on learning capabilities in immature rodents are briefly summarized and some new findings on early learning in mice are presented. We omit the comparatively small number of works concerning precocial species of rodents, that is, guinea pigs and spiny mice. In a comparison we have already made (D'Udine and Alleva, 1983) we found that rodent species characterized as precocial types appeared to be affected in a dramatic way by environmental factors during postnatal development, as shown by profound modification of their adult behavioral patterns. Since the aim of our contribution is to review the methodological paradigms used to assess early learning capabilities in rodents, we shall focus here on the Norway rat and the house mouse, because they are the only species for which evidence has progressively been built up through the use of different tests

Developmental plasticity and human health

Many plants and animals are capable of developing in a variety of ways, forming characteristics that are well adapted to the environments in which they are likely to live. In adverse circumstances, for example, small size and slow metabolism can facilitate survival, whereas larger size and more rapid metabolism have advantages for reproductive success when resources are more abundant. Often these characteristics are induced in early life or are even set by cues to which their parents or grandparents were exposed. Individuals developmentally adapted to one environment may, however, be at risk when exposed to another when they are older. The biological evidence may be relevant to the understanding of human development and susceptibility to disease. As the nutritional state of many human mothers has improved around the world, the characteristics of their offspring—such as body size and metabolism—have also changed. Responsiveness to their mothers' condition before birth may generally prepare individuals so that they are best suited to the environment forecast by cues available in early life. Paradoxically, however, rapid improvements in nutrition and other environmental conditions may have damaging effects on the health of those people whose parents and grandparents lived in impoverished conditions. A fuller understanding of patterns of human plasticity in response to early nutrition and other environmental factors will have implications for the administration of public health