Hypothalamic involvement in sexuality and hostility: comparative psychological aspects.

Evidence presented in this article shows the representation of sexual and aggressive behaviors at the level of the hypothalamus to be more prominent than in all other brain areas involved. Indeed, there are good arguments to attribute a central position to the hypothalamus within larger structural systems encompassing the limbic system, where aspects of the behaviors involved can be influenced. So far, however, the arguments are purely descriptive and factual and do not contribute much to answering questions about hypothalamic function: the grounds for and consequences of this massive representation of apparently almost all emotionally relevant social behavioral complexes, so universally established in a diversity of species, still has to be detected. A second and equally important aspect of hypothalamic function obviously has to be related to its central position within various hormonal systems. The present article concentrated on the acute dynamics and behavioral significance of activation of the pituitary-adrenocortical and pituitary-gonadal axes. Evidence indicates that the unconditioned behavioral stimuli or the consequences of behavior, but also stimuli conditioned to emotionally relevant events, may drastically alter hypothalamic hormonal regulation. Most importantly, these hormonal consequences in themselves again seem to determine further behavior and responses in relevant situations. The evidence presented with respect to reward and aversion, associated with alterations of specific hormones of the gonadal axis, may add a new dimension to our understanding of psychoendocrine functions of the hypothalamus (see also Gary, 1975; Leshner et al., 1981; Carey, 1987). Psychologically, such data can be taken as an argument for a more thorough study of the relation between memory processes and emotion (Bower et al., 1981). However fragmentary and incomplete this review may be, it will be clear that hypothalamic substrates and directly related areas, as well as affiliated hormonal mechanisms, play a central role in many of the most complex motivational and emotional syndromes and disorders. The prime idea in this is that the psychological concomitants of hypothalamic (dys)function are as much output as input, and as much the consequences as the cause within related syndromes. Such a view places the hypothalamus at the core of psychological theories of emotion and motivation, which from their most early origin have been heavily set towards hormonal and humoral changes and their relationships with psychological experience.(ABSTRACT TRUNCATED AT 400 WORDS)