• CLA Discoveries
• About CLA
• Faculty, Teaching & Research
• Students
• In the Community
• Departments & Majors
• Alumni & Friends
• News & Events
  • CLA Events Calendar
  • For the Media
  • Reach Magazine
  • RSS Feeds
  • Publications & Social Media
• Giving to CLA

Home > News & Events > CLA Today Archive > Spring 2004 : High Anxiety

High Anxiety

by Deane Morrison

Psychology researcher Jonathan Gewirtz's studies of stress and startle reactions could one day help addicts kick the habit and help us all manage fear.

Imagine two people at a party: one fresh from a great round of golf, the other weary from herding screaming kids all day. When a plate falls and shatters, which one will jump like a scared rabbit?

Surprisingly, perhaps, it's the latter. The harried parent's reaction is typical of people in a state of anxiety or fear. Whether it's everyday stress or something more serious like post-traumatic stress disorder or the agony of drug withdrawal, people and other animals react more strongly when startled if they're already in a state of anxiety.

Understanding this phenomenon—called “potentiated startle"—helps Jonathan Gewirtz, an associate professor of psychology, in his studies of brain mechanisms that produce drug addiction. The drive to reduce withdrawal anxiety plays a key role in our understanding of the addiction process and in treatment of addiction, he says.

“Withdrawal in animals gives insights into mechanisms of anxiety and drug addiction,” says Gewirtz. “Our experience implies that if you can manipulate a [drug-exposed] rat to lower its startle response back to the baseline level, that's good. If you could replicate that in people, you may help them get off drugs.”

In his experiments, Gewirtz gives a rat a drug, then inactivates a region of the brain just before ceasing drug administrations. If this blocks the withdrawal process—indicated if the rat shows a relatively mild startle response—that suggests that the brain region was involved in producing the anxiety of withdrawal.

Using this approach, Gewirtz has administered opiates such as morphine and heroin to rats and studied structures deep in the brain that are known to play a role in many emotional behaviors. After one round of drug administration and withdrawal, he was able to link certain brain structures to withdrawal anxiety. After two rounds, a related brain region—the nucleus accumbens—also came into play.

“This suggests that with repeated drug use, you recruit this area of the brain [in trying to relieve withdrawal anxiety],” says Gewirtz. “Interestingly, exactly the same area of the brain has been implicated in 'craving' for a drug to which an individual is addicted. Therefore, the nucleus accumbens could be the key to chronic drug dependence"—and thus to recovery.

In related studies, Gewirtz is looking at the neural and behavioral impact of a variety of substances. With psychology professor Chris Patrick, he is investigating the effects of alcohol on fear and anxiety. With collaborators from the pediatrics department, Gewirtz is examining the long-term effects of iron deficiency on memory. With Lisa Schrott, a former pharmacology faculty member, Gewirtz measured in rats the long-term effects—such as altered stress hormone regulation or signs of anxiety—of neonatal abstinence syndrome, a severe condition in babies born to opiate-dependent mothers.

The path to research

Like many careers, Gewirtz's has been shaped by a mix of predilection, training, love, and serendipity. Growing up in London and Manchester, England, Gewirtz leaned toward “the health care side of things, like clinical psychology,” until a tutor at Manchester University sparked his interest in how animals learn and remember. After college, Gewirtz went to London to direct a Jewish youth organization and met his future wife at an Israeli folk dance.

The two moved to Israel, where Gewirtz pursued a master's degree at Tel Aviv University and set out on the path that would one day take him to Minnesota's Department of Psychology to research memory and related brain functions.

Later, at Yale for his doctoral studies, Gewirtz watched in awe as psychiatry professor Michael Davis traced the pathway of brain and nerve signals in an animal that jumps when startled by noise.

It was only his first week in New Haven, but it was a eureka moment. “On a blackboard, [Davis] drew a diagram of how signals were passed,” Gewirtz recalls. “He had done much to trace the startle reflex from the ear to the muscles.

“I was amazed by how signals were transmitted from one brain structure to another.”

Gewirtz's interest in the startle reflex was more than academic. The Gulf War had raged while he was in Israel, and for a long time afterward, a car backfiring could put him on edge, as could an accelerating motorcycle, which revved in his brain like a siren.

Driven by his fascination with the brain, Gewirtz envisions a day when his research will contribute to the recovery of people who are substance-dependent and reveal even more about the brain mechanisms that motivate behavior or cause mental illness.

Studying the brain is studying what and who we are, says Gewirtz: “The brain is the most fascinating organ because it defines us—it is us.”