Abstract
Modulatory influence of some hormones on learning and memory. There is growing evidence that learning and memory, which are of outstanding adaptive importance for the organisms, are subjected to the modulatory influence of a number of substances and treatments. The role played in this sense by hormones rises growing interest. This paper discusses specially the involvement, in learning and memory processes, of some hormones related to stress. In general terms, those hormones related to the stress reaction tend to improve memory, while other hormones which reduce emotional strain usually deteriorate memory. Nevertheless, this general relationship depends on such factors as: a) the dose of the hormone [usually, an U-shaped relationship is observed between dose and response (i.e., the effect upon memory)]; b) the time-gap between the administración of the hormone (or its endogenous release) and treatment; and c) the intensity of the experience or of the stimuli presented during training. The mechanisms mediating the influences of the various hormones upon memory are not well known, but some of those mechanisms may have a peripherical origin.
