Dogs demand equal treats

Dogs can tell when they're being treated unfairly, and they won't take it lying down, a new study shows.

Friederike Range (University of Vienna, Austria) and colleagues carried out a behavioral experiment using trained pet dogs that knew how to “give the paw” (shake hands) on command (Proc. Natl. Acad. Sci. USA, published online 8 December 2008; doi:10.1073/pnas.0810957105). Dogs that performed the trick were rewarded with either sausage (a high-value reward), bread (low-value) or nothing.

When tested alone, most dogs were willing to shake hands repeatedly, even if the experimenter offered no reward. When a dog was tested alongside another dog (a 'partner'), however, the situation changed. In one experiment in which both dogs were told to give the paw, the partner was rewarded with bread, whereas the subject received nothing. After a short time, the subject grew visibly frustrated and refused to continue shaking hands.

This is the first time that such behavior has been documented in a non-primate species. Unlike primates in similar studies, dogs did not seem to object when their partners received a better quality reward or got treats for doing nothing, even if the subject was required to hold out its paw for the same reward.

Females can blame hormones for migraine troubles

Researchers are beginning to shed light on the mechanisms of a severe inherited condition called familial hemiplegic migraine (FHM). FHM attacks are accompanied by visual disturbance (aura) as well as a sensation of weakness on one side of the body. The condition is relatively rare and is three times more prevalent in women than in men.

FHM in humans is caused by two mutations in the gene CACNA1A. Cenk Ayata (Harvard Medical School, Boston, MA) and colleagues investigated mice that were engineered to express either one of these two mutations (J. Clin. Invest. published online 22 December 2008; doi:10.1172/JCI36059). Compared with wild-type mice, transgenic mice were more susceptible to cortical spreading depression, an advancing wave of tissue depolarization in the cortex. Spreading depression is likely to be the cause of aura, and it may be the endogenous trigger of migraine headaches.

Female mice were more sensitive than males to spreading depression and to neurological deficits. These differences were not observed in females whose ovaries were removed, though they did occur, to a lesser degree, in ovariectomized females that received supplemental estrogen. The researchers therefore conclude that female gonadal hormones have an important role in modulating FHM.

Step away from the mouse

There is no denying that mice have furthered our understanding of immunology. As subjects in basic immune studies, their utility is difficult to overstate. But by and large, the advances in knowledge that they have provided have not translated into clinically successful applications: many therapies that seem to cure mice of autoimmunity, cancer and infectious diseases turn out to be ineffective in humans. Mark Davis (Stanford University School of Medicine, Stanford, CA) believes that mouse studies have come as far as they can go alone, and that further progress requires a new approach that focuses on human immunology.

In a recent essay, Davis proposes that we should use a large-scale, 'systems biology' strategy—similar to that used to sequence and map the human genome—to clearly define human immunological health (Immunity 29, 835–838; 2008). Davis suggests that the raw material for this project is relatively accessible: blood and tissue samples from both healthy and ill people. By equipping major research medical schools with complete immune monitoring facilities and instituting a national or international program to standardize and validate the assays used, we can assemble immunological data from these samples into a more clinically relevant picture of human health.