Google search using: post-traumatic stress disorder size gives a lot: http://www.dcmsonline.org/jax-medicine/2002journals/augsept2002/PTSD.htm Discover March, 1999 STRESS AND YOUR SHRINKING BRAIN.(post traumatic stress disorder's effect on the brain) Author/s: Robert Sapolsky ............... In the last few years, however, some neuroscientists have begun to look at the bigger picture, generating magnetic resonance images of PTSD patients' brains and carefully measuring the volumes of the organs' many bewildering regions. The researchers have dotted their is and crossed their it's like good scientists, controlling for the depression and substance abuse that often accompany PTSD and controlling for total brain size, age, sex, and education. Recently, groups working independently at Yale Medical School; the Veterans Administration Medical Center in Manchester, New Hampshire, and Harvard; and the University of California at San Diego reported that in afflicted individuals an important region of the brain called the hippocampus is smaller than average. ...the hippocampus is well-explored territory. We use it to form long-term memories, retrieve old ones, and manage explicit, conscious memory. When repeatedly stimulated pairs of hippocampal neurons and their connections become stronger, more excitable: shazam--those neurons have learned something. Surgically destroy the hippocampus, as has been done in a zillion lab rats and in one famous neurological patient known only as HM, and some major types of memory will be gone for good. Similar problems result when Alzheimer's disease ravages the hippocampus. Most of the recent PTSD imaging studies have found atrophy only in the hippocampus; the rest of the brain is fine. The damage, however, is not trivial. For example, Tamara Gurvits, Roger Pitman, and their colleagues at the Manchester VA Medical Center and Harvard Medical School have studied combat PTSD patients and reported that one side of the hippocampus was about 25 percent smaller than expected. Twenty-five percent! That's like reporting that an emotional trauma eliminates one of the four chambers of the heart. These hippocampi are seriously out of whack. Research by J. Douglas Bremner and his colleagues at Yale Medical School supports that notion. Typically, when a person is given a memory task, the metabolic rate of the hippocampus increases, reflecting the energy it takes for that brain region to kick into gear. In people with PTSD, though, the same memory task fails to speed up hippocampal metabolism, a finding that fits with the memory deficits typical of PTSD sufferers. ...an atrophied hippocampus and PTSD go together, there is a lot of debate over why. One possible explanation, favored by Bremner, involves a class of steroid hormones called glucocorticoids; most people are familiar with hydrocortisone, the glucocorticoid found in humans. During stress, whether of a physical or a psychological nature, a person's adrenal glands secrete loads of these chemicals. Glucocorticoids are necessary for surviving a stressful sprint across the savanna with a hungry leopard on one's tail. They help send energy to the thigh muscles, and they shut down nonessentials, such as growth or reproduction, that can wait for more auspicious times. But however useful glucocorticoids can be in the face of an acute physical stressor, too much of the hormones--during chronic psychological stress, for example--can be a trigger for all sorts of stress-related conditions, including high blood pressure. Because the hippocampus has lots of receptors for glucocorticoids, it's the part of the brain most sensitive to the hormones. Glucocorticoids can damage neurons in the hippocampi of rodents and primates. Researchers in my laboratory and elsewhere have found a number of ways in which this happens. For starters, a few days' worth of elevated glucocorticoid levels can endanger a hippocampal neuron, making it less likely to survive a seizure, a period without oxygen and glucose, as occurs during cardiac arrest. Next, over a few weeks or months, glucocorticoids shrivel the branchlike connections between hippocampal neurons; once the stress or glucocorticoid exposure ends, the branches slowly grow back. Finally, when glucocorticoid levels stay high enough for long enough--months or years--they can destroy hippocampal neurons. These findings have unnerved some clinicians because patients with a variety of diseases are treated with high-dose glucocorticoids for long periods (even though the treatment is known to cause memory problems) and because the body itself secretes a ton of these hormones during neurological crises. Can excessive glucocorticoids damage the human hippocampus? Maybe. Consider Cushing's disease, in which any of several types of tumors produce astronomically high glucocorticoid levels. Monica Starkman and her colleagues at the University of Michigan have found atrophied hippocampi on MRI scans of people with this disease. The rest of the brain is fine, but the higher the levels of glucocorticoids in the bloodstream, the smaller the hippocampus and the more memory problems the patient experiences. When the tumor is corrected and glucocorticoid levels go back to normal, the hippocampus slowly returns to normal size, suggesting that the shriveling was reversible and the branches grew back. Is this what happens in PTSD? The model fits best if we imagine neuron loss (instead of just shriveling), because the atrophy can persist for years or decades after the trauma. Still, no one really has a clue if this is what's going on. Researchers need to study actual brain tissue, instead of pictures, to determine whether PTSD patients really have fewer neurons in their hippocampi than healthy individuals. Moreover, no one knows how high glucocorticoid levels get during a rape or a bombing. An alternative model comes from Rachel Yehuda and her colleagues at Mount Sinai School of Medicine and the Bronx Veteran Affairs Medical Center in New York. They have examined patients' glucocorticold levels once post-trauma problems emerge. To everyone's surprise, they and others have observed that levels are not higher than normal but lower. Their careful work has shown that this might be because the brain is more sensitive to the regulatory effects of glucocorticoids, resulting in less secretion (rather like making a thermostat more sensitive to minor changes in temperature). Thus, they explain the syndrome not by excessive stress hormones during trauma but by excessive sensitivity to these hormones after the trauma. In either model, what's interesting is that scientists have identified a likely culprit, a stress-related hormone known to do bad things to the hippocampus and memory under other circumstances. Naturally, the idea that trauma could cause a brain to shrink could be completely wrong, the sort of chicken-and-egg mess that often trips up scientists just when they think they've found a clue. Put a bunch of soldiers through some unspeakable hell of combat and typically only a subset of them, 15 to 30 percent, get PTSD. Maybe we have the story backward. Maybe the person with a small hippocampus who goes into a trauma is the one vulnerable to PTSD. Maybe that person processes information differently, forms memories differently, and is more at risk for flashbacks. Pitman and his colleagues have reported that soldiers who wind up with PTSD were likely to have had a higher-than-average rate of what are called "soft" neurological signs--not out-and-out neurological diseases but some minor red flags such as delayed developmental landmarks or a higher than average rate of learning disorders. Some researchers are trying to figure out whether a small hippocampus predisposes someone to PTSD. Pitman, Arieh Shalev, and their colleagues are doing a prospective study, examining MRIs of people who have just undergone a trauma and following up with later scans. The neuroscientists will examine the before-and-after images to see whether a small hippocampus really does precede and predict who will get PTSD, or if hippocampal volume decreases in the later picture. Meanwhile, Thomas Freeman, a psychiatrist at the North Little Rock Veterans Administration Medical Center, is taking another approach to untangling the question of cause and effect. If the hippocampus shrinks after the trauma, especially if it does so as a function of the ongoing post-trauma period, the extent of atrophy should be more dramatic in survivors of older disasters than of recent ones. Freeman and his colleagues are comparing brain scans of PTSD victims from the Gulf War, Vietnam, Korea, and so on. Although the recent hippocampal research has little to say about everyday stress and recovered memory, it does have some valuable practical lessons for us. If a small hippocampus is indeed a risk factor for PTSD, neuroanatomy should be taken into account when we decide whom to ship off to battle, the same way we'd consider the presence of a heart murmur. And if the atrophy is a consequence of the trauma or the post-trauma period, scientists have their usual marching orders: figure out how the process works so we can learn how to prevent it. RELATED ARTICLE: The Aftermath of Severe Trauma * The National Institute of Mental Health defines post-traumatic stress disorder as "an extremely debilitating condition that can occur after exposure to a terrifying event or ordeal, in which grave physical harm occurred or was threatened." * At least 4 percent of adults in the United States (5.7 million people) suffer from PTSD every year. One million Vietnam veterans have developed the disorder, as have nearly one in three people who have spent time in war zones. * Triggers include military combat, violent personal assault (rape, torture, physical or sexual abuse), accidents (car wrecks, plane crashes), natural disasters (floods, hurricanes, earthquakes). Families of victims can also develop PTSD. * PTSD sufferers may experience flashbacks in which they feel they are reliving the ordeal. They may have trouble falling asleep or stay awake because of nightmares, night after night. I hey may reel emotionally numb and cut off from the people closest to them. They may have terrifying intruding thoughts or memories. They may turn to drugs or alcohol to keep their thoughts and feelings at bay. They may become depressed, anxious, or irritable, snapping or lashing out at people around them. And they may suffer from extreme feelings of guilt, as if they should or could have prevented the disaster. * Anyone who goes through a severe ordeal risks developing the disorder, but the threat is greatest for people with previous traumatic experiences--particularly those who were sexually, physically, or emotionally abused as children. * PTSD patients are often given antianxiety or antidepressant drugs, such as nefazodone and trazodone, to treat symptoms of depression, anxiety, and sleeplessness. Behavioral and cognitive-behavioral therapy can also be useful. For example, a therapist may teach a patient to head off panic attacks by taking slow, deep breaths. The therapist may gradually expose the patient to images or sensations that remind him of the trauma (battle photos, loud noises), then help him deal with the fears that come up. ROBERT SAPOLSKY ("Stress and Your Shrinking Brain,"), a professor of neuroscience at Stanford who studies stress-induced diseases, says he and his colleagues have been waiting for years to get a good look at the brains of people who suffer from such maladies as depression and post-traumatic stress disorder. Now that imaging techniques have finally caught up, researchers have been able to confirm their -ideas. "In 1990 you could resolve a 5-millimeter slice of brain," says Sapolsky. "Now it's .5 millimeter. I assume we'll get to a point where if you're just walking down the street, someone can image you from 30 stories up and find out if you flossed your teeth that day." Sapolsky is the author of Why Zebras Don't Get Ulcers. ------------------------------------------------------------------------------- COPYRIGHT 1999 Discover NATURE NEUROSCIENCE NOVEMBER 2002 PRESS RELEASE -------------------------------------------------------------------------------- NATURE NEUROSCIENCE NOVEMBER 2002 http://www.nature.com/neuro/press_release/nn1102.html A RISK FACTOR FOR POST-TRAUMATIC STRESS DISORDER Post-traumatic stress disorder (PTSD) develops in response to traumatic events, such as kidnapping or war. Its symptoms include flashbacks, nightmares, jumpiness and emotional problems. PTSD may be more likely to occur in people with pre-existing damage to the hippocampus, a brain area involved in memory and stress responses, reports a paper in the November issue of Nature Neuroscience. This finding could help predict which individuals may be particularly sensitive to stressful experiences. Previous work had shown that the hippocampus is smaller than normal in PTSD patients. Because stress can damage this brain region, though, most researchers concluded that PTSD had caused the hippocampus to shrink. No one had looked at brain scans before and after PTSD developed, and so it remained possible that the brain damage was present before the trauma. In the new study, the authors addressed this question by examining identical twins in which one brother was a combat veteran of the Vietnam War, while the other had remained at home. As expected, the hippocampus was smaller in combat-exposed brothers who developed PTSD than in other veterans who did not develop the disorder. But to the researchers' surprise, this brain region was also small in the stay-at-home brothers of the PTSD patients. In other words, the hippocampal size of the twin who was not exposed to combat predicted whether his soldier brother would develop PTSD. Because identical twins typically have similar brain structures, this finding suggests that the hippocampus was probably small in the PTSD patients before the trauma, which may represent a risk factor for the development of PTSD. In an accompanying News & Views article, Robert Sapolsky cautions that much work is needed before a definite cause-and-effect relationship between PTSD and brain trauma can be determined. --------------------------------------------------------------------------------