Similarly, sexual and feeding behavior, while

largely conserved at the neural system level, is also expressed behaviorally in diverse ways within mammals. For example, although androgen activity in the hypothalamus is important in all male mammals, the semen delivery process varies in males, in part because of different approaches required given the configuration of the male and female body (e.g., Pfaff, 1999). This is perhaps most dramatically illustrated by the lordosis posture of female rats. The male cannot insert his penis into the vaginal cavity of a female unless she arches her back to adopt this posture, http://www.selleckchem.com/products/Fasudil-HCl(HA-1077).html which is regulated by the binding of estrogen during the fertile phase of her cycle (Pfaff, 1999 and Blaustein, 2008). Further, some mammals use their snouts when eating and others their paws/hands, but the core circuits described above nevertheless regulate the various homeostatic and behavioral functions required to regulate energy and nutritional supplies. Thus, the responses used by survival circuits to achieve survival goals can be species-specific even though the circuit is largely species-general (obviously, there must be some differences in circuitry, at least in terms

of motor output circuitry for different kinds of behaviors, but the core circuit is conserved). By focusing on the selleck chemicals llc evolved function of a circuit (defense, reproduction, energy and nutrition maintenance, fluid balance, thermoregulation), rather than on the actual responses controlled by the circuit, a species-independent set of criteria emerge for defining brain systems that detect

significant events and control responses that help meet the challenges and opportunities posed Aciclovir by those events. A key component of a survival circuits is a mechanism for computing circuit-specific stimulus information. A defense circuit needs to be activated by stimuli related to predators, potentially harmful conspecifcs, and other potential sources of harm, and not be triggered by potential mates or food items. The goal of such computational networks is to determine whether circuit-specific triggers are present in the current situation, and, if a trigger is detected, to initiate hard-wired (innate) responses that are appropriate to the computed evaluation. Such responses are automatically released (in the ethological sense—see Tinbergen, 1951, Lorenz, 1981 and Manning, 1967) by trigger stimuli. The nature of behavioral responses released by survival circuit triggers should be briefly discussed. Activation of a survival circuit elicits behavioral responses on the spot in some cases (e.g.