The Bounce-Back Effect

First Published: Chicago Reader, September 1, 2000

Adolescence is difficult everywhere but nowhere more so than on Cayo Santiago. A thousand rhesus monkeys share this tiny island paradise just off the coast of Puerto Rico, virtually unbothered by humans. But when they reach adolescence, young males are subject to a treacherous social test. Leaving the troupes of their mothers, they go out to seek their fortunes, make new friends, find their way into a new troupe – and a quarter of them die trying to do it.

“We don’t know why,” says Dr. Ned Kalin, who’s been studying the monkeys on yearly visits since 1992, but he expects it has to do with their emotional dispositions, their affective style. In this circumscribed habitat, Kalin and his fellow researchers can follow the progress of individuals. They make detailed social observations – they know who is related to whom, who gets groomed, and who has lots of friends – and every year they take a battery of physiological measures. They’re expecting they’ll find that monkeys with outgoing personalities share certain biological features, features that will also connect with their ability to deal with the stress of leaving home. “We’re trying to predict who’s going to be able to make that transition in a very effective way and who’s going to be vulnerable to not do it so well, and maybe even die in the process.”

Kalin is the Director of the HealthEmotions Research Institute, which has assembled what is probably the largest concentration of emotions researchers anywhere, in Madison Wisconsin. Affiliated with the University of Wisconsin, the Institute has recently received an $11 million grant from National Institute of Health, and lots of media attention, for its all-fronts approach to figuring out the biology of positive and negative emotions and how they impact health. Their efforts coordinate the most basic cell biology with lab rat and primate research, human brain imaging and long term population studies.

The Institute’s researchers have identified a constellation of qualities that make for what they call a positive affective style. Generally the monkey with the positive affective style is the one who tends to move forward in the world where others are uncertain. It’s not that he’s shallow – he still suffers the kind of fear, anxiety and sadness that afflicts most mortal primates, but he gets over it faster.

Kalin’s colleague, Dr. Richard Davidson describes the positive affective style as the “ability to feel emotions deeply but appropriately, then rapidly recover.” Director of the university’s W.M. Keck Laboratory for Functional Brian Imaging and Behavior, Davidson sees no reason happiness should be limited to the lucky few born with good brain chemistry or the right neural wiring. As they learn how affect is determined by genes and shaped by life experience, researchers at the HealthEmotions Research Institute are also asking how we might improve it, by medication, behavioral therapy, or age old meditation techniques. “There’s no reason to think of emotional reactivity as a skill any different from other skills,” Dr. Davidson told the audience at the Institute’s Symposium on Positive Emotion this spring. He urged them to imagine the day when we could be emotional athletes, pressing the limits of emotional resilience.

For years, neuroscientists have avoided the emotions – they’d study sense perception, cognition, even try to put their fingers on the seat of consciousness itself before they’d muddle into the tangled circuits of affect. Partly they didn’t have the tools to place their theories in the live human brain. They could take pictures of its structure, or they could mark its electric pulse with electrodes taped to the scalp, but they couldn’t take a good picture of it that showed which parts were activated until the advent of functional Magnetic Resonance Imaging – a process for imaging changes in blood flow, the fMRI requires a phenomenally expensive piece of machinery that didn’t come online for brain research until 1991.

Animal brains are more accessible. They can be sliced into sections and treated to mark the presence of particular hormone or neurotransmitter systems; you can grind them up and separate out specific receptors, or penetrate them with surgically implanted electrodes to see which part a rat will self-stimulate and which parts he won’t. Neuroscientists have learned their way around the brain of a rat so well they can implant tiny instruments to measure the firing of particular neurons in a live animal. Yet even with all this, it’s hard to know exactly what the rat is feeling.

Beyond the practical considerations there may be some lingering fear that emotions research isn’t quite decent. Neuroscience textbooks still include cautionary reference to the phrenologists, that school of 19th century scientists who thought they could read a person’s character from the topography of his skull. Now, as the field ventures into emotions and personality, they say they’re teasing apart the intricate exchanges among the brain’s structures, they’re learning the many roles of its neurotransmitter and hormonal systems, but they never point to any one lump or region and say “fear occurs here.”

When Edmund Rolls came to Madison this spring to speak at the HealthEmotions Institute’s symposium, which is an annual event, he brought out the cover of his most recent book, The Brain and Emotion, with its illustration of Pandora and her awful box. Pandora wasn’t sure if she should look in the box, he reminded his audience – are we? Then he launched into a sober discussion of whether the neurons in the orbito-frontal cortex of a rat can differentiate between the promise of a glucose or a saline reward.

It doesn’t sound very emotional, but then “emotions are states elicited by reinforcing stimuli,” he says; he challenges his audience to think of an emotion that can’t be traced back to reward or punishment. Our genetic codes are relatively rigid he muses. Emotions may have evolved as a sort of interface that gives an organism the flexibility to react to the vagaries of the external world.

Not everyone at the Symposium would describe emotions so operationally as Edmund Rolls, but emotions research is still built on the most basic cell biology and a strong sense of evolutionary function. So the scientists haven’t come to Madison to delve into the nuances of their messier sentiments. They talk about pleasure and pain, reward and reinforcement, the tendency to approach or withdraw in response to a stimulus.

After all, how do you know when a rat is feeling anxious? The researchers at the HealthEmotions Research Institute use a maze for the purpose, some of its corridors are dark and enclosed, some are open to the light. It’s designed to bring out conflicting impulses in a rat. On the one hand, the bright parts are so interesting he wants to rush out there and see what’s going on; on the other hand, they’re novel, a little scary, he’ll feel more secure in the darker parts of the maze.

Say you expose the rat to the scent of a predator, they you drop him in the maze to see what he does. If he retreats to the dark corners he’s withdrawing in response to the stimulus; if he shuns the dark and makes his way out into the bright exposed parts anyway, he might be feeling brave, giddy, curious or defiant. But he has apparently overcome his impulse to withdraw in response to a threatening stimulus and let his desire to approach win out. And at a distance, he looks like a rat with a positive affective style.

The scientists at the HealthEmotions Research Institute aren’t the first to point to the approach/withdraw response as a substrate of emotion, but they are doing important work tracking the systems that regulate it. In fact, they argue there are 2 distinct pathways, one that activates the emotion, and one that effectively decides when to shut it off. Kalin and Davidson have split the pursuit between them.

Kalin directs the labs that are unraveling fear, anxiety, negative emotions as they’re activated in the primitive regions of the brain’s limbic system. Much of his work centers on the corticotropin releasing hormone, or CRH. Starting in the amygdala, a small emotional powerhouse deep in the brian, CRH triggers the production of adrenocorticotropic hormone, which triggers the release of cortisol, a stress hormone so caustic it may virtually scorch the brain during particularly stressful events, especially young brains, leaving permanent impairments in the emotional circuits. Labs at the HealthEmotions Research Institute are stressing rats, slicing their brains, looking for where the CRH system is expressed; they’re unraveling the genetic code that determines it, and studying how strong, steady pulses of CRH might cause the proteins that receive it into the cell to permanently retract, which might be the mechanism by which traumatic stress can affect permanent disorders.

Meanwhile, they’re injecting drugs that block CRH from working into different parts of the limbic system of rats, to see if treated rats are less likely to cower in the dark parts of the maze. Is this really a rat with a positive affective style? “You could think of people who are emotionally resilient as having a CRH system that more rapidly comes back into control, and we’re sort of artificially doing that by giving rats a drug that blocks a receptor…,” Kalin supposes, though technically the experiment is set up to study the activation of anxiety. They may even be blocking the anxiety before it occurs. The positive affective style is the ability to turn negative emotions off after they’ve started, and that’s associated with the other end of the system.

The prefrontal cortex is the skin of the front part of the brain’s more sophisticated frontal lobe – the lobe associated with cognition and intelligence. Davidson first suspected the prefrontal cortex had some role in regulating emotion when he learned that patients with lesions on the left side tended to be melancholy and depressed, while those with damage on the right were cheerier, even manic.

To check it out, he assembled 90 right handed subjects and covered their scalps with a net of electrodes to compare patterns of electrical activity underneath. He tested them to see which side of their prefrontal cortex seemed to be more active. Then he had each take a questionnaire designed to test their tendency to be active or inhibited in their behavior, and he compared the results. Sure enough, people who answered yes to statements like “When I want something, I go all out,” were more left lateral than those who saw themselves in statements like “When I want something, I worry I’ll make a mistake.”

To figure out whether the people with more left dominant prefrontal cortices were just oblivious to the darker possibilities in the world, Davidson devised a clever experiment based on the fact that most people (with the exception of some sociopaths) blink when they are startled. If they are upset when they’re startled, they blink longer.

To get an emotional reaction in the limited environment of the lab, they used a set of photographs developed by University of Florida researcher Peter Lang. Some of the pictures are meant to evoke positive reactions – babies, puppies, nude people – others provoke negative ones – violent car wrecks and the like. The pictures have been tested across hundreds of subjects whose reactionsare averaged, and the pictures have been ranked for their evocative power.

Davidson showed his subjects negative pictures, startling them with a loud noise beforehand, and then again while they were looking at each picture. Then he startled them several times immediately afterwards to see how quickly they recovered. Right laterals continued to show strong startles after the picture was gone, in fact they seemed to get more upset in the moments after their first impression. Left laterals showed strong startles when the picture was shown, in some cases they had stronger reactions than the right laterals, but their startled blinking diminished more rapidly.

At the Symposium, Davidson lists a host of other positive qualities his left lateral subjects enjoy – everything from positive affect while they’re dreaming to greater ability to anticipate positive incentives. When he’s through, there’s a question from the audience – someone wants to know if there isn’t some point at which all this positive affect is maladaptive? A little later, someone else asks the same thing, citing studies that link right lateral activity to empathy, for instance. Maybe these people were wondering if they would want to be surrounded by people who jump out of bed in the morning and go all out, or maybe they’re not sure they like the idea there could be an absolute standard of emotional health.

Davidson isn’t claiming to have discovered the absolute standard, but he reminds them again, it’s not that his left lateral subjects don’t feel negative emotion – in some cases they feel it more deeply, but “appropriately.” Then they rapidly recover.

Of course, we could all stand to feel emotions more appropriately, to recover more quickly. Identifying the basis of healthy emotion opens up the possibility that we can move toward it. In fact, we adjust our emotional behavior to what’s appropriate every day – a capacity that Davidson has confirmed in another experiment with disturbing pictures and startling sounds. This time, the lab instructed each subject to either enhance, or suppress, or maintain the emotion inspired by the card – and it turned out people really can suppress their emotional blinking, just by deciding to. Though of course the left lateral people did it better.

But to what extent can we change the balance of the circuits themselves? Doctors at medical centers scattered across the world, including the Harvard Medical School, have already begun treating depressed patients with magnets to see if they can stimulate their left cortices, and at Northwestern University in Evanston, Dr. Peter Rosenfeld has development a system that may help train you to swing your prefrontal activity toward the left with neurofeedback. He says most of his patients have been successful, though he cautions the method needs to be studied with a control group.

Davidson has been exploring the powers of mediation. In a study with Jon Kabat Zinn at University of Massachusetts Medical Center in Worchester, executives of fast paced biotech companies were trained in mediation techniques. Other experiments have involved Tibetan monks. Davidson isn’t talking about the results though, since he’s just submitted a paper for publication.

There is tentative evidence that some anti-depressants make patients more left lateral, though it’s unclear how long the effects last. In the past, Kalin has suggested behavioral training could teach extremely inhibited people to regulate mood altering neurotransmitter systems without being medicated. Now he says “Exposing people to what scares them has been shown to be effective for treating lots of anxiety problems. One of the best ways to get over a fear is to get that person to be in a scary situation so their bodies get used to it, and they realize that what’s really scaring them is their physical response.” If such exposure tones down the CRH system, this might be the mechanism by which such de-conditioning occurs – “but that’s a big might,” he adds with the caution of his field.

Davidson’s left lateral subjects, with their positive affective style, sound a little like the patients taking selective serotonin reuptake inhibitors, or SSRIs, in Peter Kramer’s Listening to Prozac. At least Kramer argues his patients haven’t become terminally cheerful, or oblivious to pain, they’ve just acquired a new ability to bounce back from adverse circumstance, they’ve acquired a new emotional resilience – and apparently without the discouraging side effects that have limited the use of other anti-depressants.

Davidson is skeptical that they’re talking about the same thing. “I don’t know of a single study that has rigorously examined the effects of SSRIs on the rapidity of recovery following a negative event.” Though serotonin does reduce CRH levels, “we’re thinking that’s one of the ways it works actually,” Kalin says. And together, he and Davidson have found that left lateral monkeys have lower levels of CRH than their less resilient, right lateral peers. Someday, the HealthEmotions Research Institute’s work on CRH blockers might translate into drugs that bypass the serotonin system, reducing anxiety and maybe avoiding the sexual dysfunction, which is the one really discouraging side effect the SSRIs turned out to have.

Kramer was so impressed with the glorious effects of Prozac that it made him uneasy. There are some ethical questions raised by a drug that doesn’t just make people more peppy, or more relaxed – those scales hit limits where they're not advantages anymore – but one that makes people more lucid in their thinking, quicker to make decisions, more resilient. He describes a patient who found Prozac made her more effective in her role as a representative of corporate interests in labor negotiations – leaving him wondering if labor should have been offered Prozac too.

Having moved past vague definitions of happiness and set their sights on the more practical goal of emotional resilience, emotions researchers are describing a set of fairly competitive behaviors. And why shouldn’t they be competitive if emotional health is adaptive, if neural circuits contribute to individual survival, and evolutionary advantage?

Is the positive affective style, with its roots in approach oriented behavior, just a
competitive personality? Kalin is thoughtful, “Positive affective style, or a resilient personality and so on, these terms are relatively new. So the idea that that kind of a person might be very outgoing, or very approach oriented, or very competitive, is an interesting idea.

“My thought is that they don’t necessarily go hand in hand. You can have a person who is very positive, adaptive, healthy emotionally, who is not necessarily terribly competitive. You could also submit that if it’s very competitive, it’s not very healthy emotionally,” or very adaptive. Very competitive people might have trouble getting along with others if they’re not considered empathic, for instance.

Ultimately, he says, “the healthiest emotion style is to be able to experience a full range of emotions appropriately, but also to be able to turn them off when it’s not appropriate.” You can’t argue with a standard defined as what’s appropriate, but if we learn to recover more rapidly, what is appropriate will probably also change.

When Kalin, who is Chair of the University of Wisconsin, Madison’s Department of Psychiatry, writes about anxiety among monkeys, he frames his research in the context of what science might do for an anxious child. Biologically based anxieties won’t necessarily lead to physical illness, or death, but they will make his whole life more difficult, and may start “a vicious circle leading to isolation, low self esteem, under achievement, and anxiety and depression.” Kalin’s research on Cayo Santiago, where as many as a quarter of the males really do die from the pains of adolescence, illustrates the gravity of emotional pain. On the other hand, if so many monkeys already die because they can’t find a place for themselves in the world, how would they fare in a colony of emotional athletes?

Is positive affective style just very competitive behavior? “There are certainly some important areas of overlap,” Davidson says. For instance, some scientists have found that anger, particularly anger directed to remove some obstacle to an individual’s goal (“an important function of anger,” Davidson adds), is associated with a similar pattern of brain activity as the positive affective style. “Undoubtedly, as we begin to look more closely at these emotional states and characteristics we will discover other differences between an approach oriented style that is tinged with anger and one that is more unequivocally positive.”

This doesn’t mean that as we develop emotional prowess, we will be angrier, any more than cultivating our recovery times will mean we’ll all become cut-throat competitors in a spinning global economy, or that we’ll toss out our brooding novels for the faster fare of MTV. Whatever the evolutionary purpose that gave us emotions in the first place, it’s our emotions that make us cling to things that aren’t practical, that don’t move the race forward, that aren’t always advantageous to us as individuals. It’s because of them that we don’t want the monkeys with poor affective styles to perish, and maybe we don’t even want to be people who jump out of bed in the morning, impatient to go all out. But if everyone else is going to be like that, we might consider medication.

Or we might turn to other methods. In a one-time experiment, Davidson flew a Buddhist monk in from Dharmasala India to give him his EEG test for left or right laterality. When he placed the result on a scale with 175 of his regular subjects to see who had the most left lateral prefrontal cortex, it was the gentle man from Dharmasala who came out on the furthest extreme of the scale.

Photo: Aleksandar Todorovic /

No comments:

Post a Comment