Researchers in the Nancy Pritzker laboratory of the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine in the United States have shown in a new study that chronic pain can cause changes in a certain area of the brain, resulting in a decrease in motivation in mice. .
Chronic pain changes the connection of neurons in the nucleus accumbens with the help of a neuropeptide called galanin, which leads to underpowered behavior. However, the researchers also noticed that this effect can be reversed by blocking the effects of galanin. Clinicians know that in humans, chronic pain, depression, and decreased motivation to accomplish long-term goals are often closely related.
To explore these connections, Neil Schwartz and colleagues looked at neurons taken from mice that suffered from two types of chronic pain, including injections of inflammatory substances in the soles of their hind feet and by damaging their sciatic nerves. And the pain caused. Researchers tested the motivation level of mice by testing whether they would try to overcome increasingly difficult obstacles in order to obtain food rewards. Mice with chronic pain are less motivated to overcome these obstacles than other mice, even when they are given analgesics to relieve the pain.
Schwartz and colleagues concluded that this decline in motility seems to come from galanin-dependent changes in the motility neural circuit. In a related "Perspective" article, Howard Fields discusses these results in the context of other recent discoveries about the basis of dynamical nerves.