ABSTRACT
The study of the behavioral effects of apparently irrelevant sensory and motoric events on reflex expression in the alert and behaving animal began toward the end of the nineteenth century, when it was becoming understood that reflex activities are not driven by stimuli acting through fixed and isolated sensory-neural pathways, but are very sensitive to subtle events of psychological significance and, thus, by complex neural activities in the brain. These early experiments on reflex modification (described in Ison and Hoffman, 1983) studied the basic phenomena of reflex modification and also its application, and demonstrated the strength and ubiquity of prestimulus effects in species as disparate as frogs (Yerkes, 1905) and humans (Lombard, 1887; Bowditch and Warren, 1890). These workers showed that both facilitation of reflex expression and its inhibition can be produced by near-threshold stimuli and by the initiation of voluntary movements, the outcome depending on small differences in the timing between their onset and subsequent reflex elicitation. Some variables that affect the strength of these reflex phenomena are important in other research domains, notably sensation and perception (L.H. Cohen et al., 1933), emotion (J.S. Brown et al., 1951), and aspects of psychopathology in humans (Braff et al., 1978). The comparability of reflex findings in rats and humans has supported the development of animal models in these areas that prove useful in understanding both normal function and disease, and this has extended the scope and the importance of research on reflex behavior. Recent advances in molecular biology have made inbred, transgenic, and knock-out mice the most powerful animal models for analyzing the functional effects of gene expression. The purpose of this chapter is to review the research on reflex elicitation and modification in mice, in order to extend these models for the more fruitful neurobehavioral analysis of genetic manipulation.
