Stress, self-injury link to be discussed at neuroconference

A UF researcher’s effort to understand self-injurious behavior will be featured when neuroscientists from around the world gather Nov. 2 in Orlando.

Research into the neurobiology of stress responses and self-injurious behavior by Darragh P. Devine, Ph.D., is among topics the Society for Neuroscience will present for public release at its 32nd annual meeting. The event annually draws more than 25,000 neuroscientists, with more than 20 UF researchers expected to attend this year.

Devine has discovered that rats that are more easily stressed than others also are more vulnerable to develop behaviors that lead to self-injury.

“This finding may help explain why some autistic and intellectually handicapped children deliberately hurt themselves while others do not,” he said.

Self-injurious behavior is a devastating, often life-threatening disorder that is suffered by many autistic and intellectually handicapped people, Devine said.

Devine, a professor of psychology who works with the Evelyn F. and William L. McKnight Brain Institute of UF, focused on the behavior that leads to injury. Other studies almost exclusively consist of examinations of traumatized tissue, without detailed behavioral analysis, Devine said.

Ultimately, Devine and his team want to characterize individual differences in the development of self-injury to better define the progression of this devastating disorder.

“It may tell us why some humans injure themselves and some do not,” Devine said.

An additional distinction between Devine’s work and previous research is that Devine’s experiments do not inevitably lead all of the subject animals to the point of self injury, which reflects the fact that some but not all children with autism exhibit head-banging behavior. Devine and his team regulate the dose of pemoline, a drug that resembles Ritalin and amphetamine, so that about 50 percent of the subject animals will self-injure, while 50 percent will not. The experiments last six days. When the self-injurious behavior occurs, the experiment is ended because the researchers do not want the animals to seriously harm themselves, Devine said.

“We find that rats that are more highly responsive to a mild stressor, such as a new environment, secrete greater amounts of stress-related hormones,” he said. “Some of the rats run around a lot and secrete a lot of hormones. These rats will more readily exhibit self-injury than will rats that do not respond so highly to the mild stress.”

Devine and his team are now examining how these individual differences arise. They measure the behaviors of rats living in an enriched environment compared to a stark one.

“We begin at weaning, 21 days after birth. Some rats have toys, nests, things to play with and social interactions,” Devine said. “Others are in a simple metal cage. We want to find out if those differences affect stress response and vulnerability to self-injury.” Soon, the UF researchers will analyze the rat brain tissue on a molecular level.

“We’ll look at the expression of the genes, differences in the neurotransmitters, things that make one rat different from the next,” Devine said. “We’re looking at some manipulations that may make rats more vulnerable or less vulnerable to self-injurious behavior. The rat brains will show us what to look for in the human brain.”