A new study found that the sense of anxiety or pain from enduring an accident or any injury usually felt by humans can also be present in any animal such as the squid.
The findings from the research show that behaving in a counterproductive manner may at times have an advantage when seen from an evolutionary point of view.
“Many pain researchers and clinicians consider long-lasting sensitization and associated pain to be maladaptive, rarely considering whether it might be evolutionarily adaptive. Intense pain is certainly maladaptive in many human contexts when modern medical care is available. However, this study provides the first direct evidence for the plausible evolutionary hypothesis that sensitization mechanisms – which in some animals are known to promote pain – have been shaped by strong evolutionary selection pressure, including pressures from predators,” said Edgar Walters from the University of Texas Medical School, in a press release.
For the experiment, the researchers placed squid and black sea bass to swim freely in laboratory tanks. They observed that the squid could still swim normally around even after getting an injury in one of their arms. However, they are still in a disadvantaged position since the bass would continue pursuing the injured squid more compared to pursuing those that are uninjured. This pursuing activity even goes on at greater distances.
It further shows that once the injured squid becomes the pursuer’s target, they would act more defensively, as well.
The most intriguing aspect of the experiment is the injured squid’s survival value of heightened vigilance. After the squid is treated briefly with anesthetic, disabling its nervous systems to register the injuries, it was not able to respond with enhanced defensive behaviours that could have helped it to survive.
The findings suggest a totally different way of evaluating how humans react to injury and pain.
“If we can understand more about what the natural, ‘intended’ purpose of nociceptive sensitization is, we might be in a better position to find new ways to treat its pathological expression in human, “said Robyn Crook, lead author of the study.
Further details of the study can be read on the May 8 issue of Cell: Current Biology.
