What injured squid can teach us about irritability and pain - LA Times

A new study involving injured squid and hungry sea bass may help explain why we are so grumpy and irritable when we are in pain. For many of us, the unpleasantness of being in pain often goes beyond the agony of the injury. If we are in excruciating discomfort, suddenly it seems everything bothers us -- sounds are too loud, lights are too bright, and even a gentle touch can be uncomfortable. "One of the effects of pain is the peripheral sensory system becomes hyperactive," said Edgar T. Walters, who studies pain and neural plasticity at the University of Texas Medical School at Houston. "People in pain are very easily irritated and we found that this fits in with a primitive pattern designed for an animal to be extra-vigilant." Walters is the senior author of a new study in the journal Current Biology that looks at how squid react after having the end of one of their arms snipped off -- a relatively minor injury by squid standards. The researchers put four injured squid in a tank with four squid predators -- in this case, sea bass. Then they compared the injured squids' behavior to four non-injured squid who were put in the same predator-heavy conditions. The injury was subtle enough that it didn't effect the squid's ability to swim or maneuver in the water. However, the researchers found it did affect the behavior of the squid. "The injured squid were really touchy," said Robyn Crook, an evolutionary neurobiologist at the UT M...
Source: Psychology of Pain - Category: Psychiatrists and Psychologists Source Type: blogs