Rejection really does hurt as research links emotional and physical pain

10/10/2003

Rejection packs the same painful punch as a blow to the gut as far as your brain circuitry is concerned.

In today's issue of the journal Science, a researcher from the University of California Los Angeles used brain research to show that even the mildest rejection activates the same part of the brain that registers physical pain.

It's also a nifty demonstration of the way evolution builds on a primitive system. A brain circuit critical to our survival - the awareness of pain - creates an emotion linked to infant survival - the need to keep mother close by.

Nearly 30 years ago, a Bowling Green researcher made the same observation, only he did it in the brains of guinea pigs. Since the 1970s, Jaak Panksepp has studied the emotions that evolution etched into mammalian brains. As a result, Dr. Panksepp saw his funding disappear, and his papers rejected. He lived an outsider's life in the field of neuroscience.

In short, he learned about rejection from the inside out, as well as from the outside in. Now, finally, neuroscience seems to be approaching for a rare embrace.

“He was probably one of the first people to talk about this: that the system that keeps us close to other people piggybacks on the pain system,” said Naomi Eisenberger, the lead author of the paper in Science.

Now, the researcher who insisted - over the protest of an entire field - that animals have emotions, that they feel separation, and caring, and that what they feel is critical to understanding the human brain, is finally able to feel a bit of acceptance himself.

The Science article, for which he wrote a commentary, is the most recent sign that Bowling Green just may be home to one of the leading thinkers in neuroscience.

In Ms. Eisenberger's Science publication, she showed that adults are exquisitely sensitive to rejection. Using functional Magnetic Resonance Imaging, she watched what happened in the brains of subjects playing a video game of catch.

The research subjects were not told that the other players were computer-generated. At first, the subject was included in the game, and the other “players” toss him the ball. But as the game progressed, the subject was left out.

Each subject of the study said he felt rejected. And in each brain, his pain circuitry - centered in a structure called the anterior cingulate cortex - lit up.

The pain circuit gets its first emotional workout in infants, Dr. Panksepp says. But the statement is controversial.

Separate a baby from its mother and it cries: kittens, puppies, rats, guinea pigs, humans. It's a universal mammalian response.

While most of us see the whimpering as an expression of distress, not all scientists agree.

You cannot see inside the puppy's brain. You cannot know its feeling. You can describe its behavior, but you cannot say what that behavior means.

“I'm not comfortable projecting my feelings onto my spouse; so I'm sure not comfortable projecting them onto a rat,'' says Mark Blumberg, a psychology professor at the University of Iowa. He is one of many neuroscientists reluctant to speculate on animal feelings.

His own research suggests animal separation cries may convey no more emotion than a sneeze. They appear to be the physical response to reduced body temperature. The cry may be part of an automatic reaction the animal uses to squeeze blood from its limbs back to the heart.

That's it. No emotions. Just data and a hypothesis.

That approach represents the way all neuroscience conducted itself when Jaak Panksepp first mapped the brain circuits for the crying baby animal.

“When we were developing our ideas, to say an animal felt pain was to indicate you were outside the main camp.” Of course pain can't be seen, Dr. Panksepp acknowledges. But it can be measured.

He learned he could provoke emotional responses in animals just by stimulating the right parts of the brain.

“You can make an animal appear happy, appear scared, appear lonely,” he said. But what did that really mean? Standard neuroscience said it did not necessarily mean anything.

“I am the fool who went the one extra step and said, I'm sorry, all the data indicates the animal also has the emotional experience,” Dr. Panksepp said.

And that's how he got into trouble.

“He has been an outsider, quite frankly,'' says Thomas Insel, the director of the National Institute for Mental Health. “Jaak's not somebody who has been at the core of neuroscience because he was there way ahead of his time.”

There is more than a little cruel irony in the fact that Dr Panksepp bears perhaps more than his share of difficult emotions. His daughter Tina was born a few years after he began studying emotions. When she was 1 year old, he became both mother and father to the girl when his first marriage ended.

Then, in 1991, his daughter and three of her friends were killed in an automobile accident in Bowling Green. A drunken driver hit her car broadside.

He's not maudlin, but Dr. Panksepp makes no secret of this tragedy. He mentions his daughter's death in the footnotes of the commentary he wrote in this week's Science. Her silhouette is imprinted in his 1998 book, Affective Neuro- science.

In 1998, Dr. Panksepp brushed against fame. It wasn't so nice. People Magazine wrote an item about him. News of the Weird, a compendium of the day's strangest news stories, gave him a mention. Ripley's Believe It or Not featured his work in one of its cartoons.

His feat: He'd discovered rat “laughter.”

It was a strange moment. He had just authored a book that synthesized the ideas of his career. It was the summary he hoped would put him on the map. Yet he found himself instead at the center of attention that was more silly than serious.

Few seemed very interested in why he looked into rat vocalizations. But, at the heart of rat laughter, Dr. Panksepp suspects, will lie some of the secrets of human joy.

Fear, anger, seeking, sadness, lust, care, and play. Those are the core emotions, the ones we share with other mammals before we add our higher-brain spice to come up with complex mixtures such as jealousy.

He found rats making high-pitched squeaks as he studied play. All young mammals play, and Dr. Panksepp suspects such play is critical to organizing the maturing brain..

Yet while he was fielding questions about “giggling” rats, something serious was happening. His book was gaining notice.

Shelley Taylor, a psychology professor at UCLA, calls it “one of the most important books I've ever read, in terms of its impact on my thinking and my research.”

“His book will widely be regarded in time as sort of a landmark,” said Douglas Watt, director of neuropsychology at the Quincy Medical Center near Boston. “I would consider it to be one of those touchstone pieces.”

Finally, it appears Dr. Panksepp's work is gaining acceptance.

“I didn't write the book to gain acceptance,'' he said. “I wrote it to project young thinkers into the future. So success for me would be if many young investigators start pursuing these issues.”