Brian Handwerk
From National Geographic News

January 17, 2007
Amnesia may rob people of their imaginations as well as their memories, new research suggests.

"What we've shown is that people with amnesia really are stuck in the present," said lead study author Eleanor Maguire of the Wellcome Trust Centre for Neuroimaging at University College London.

"They can't recall the past, and now it seems that they can't even imagine the future or indeed richly imagine even fictitious experiences."

Amnesia, which is sometimes temporary, describes several conditions that involve partial or complete memory loss.

Brain damage, tumors, strokes, or even psychological issues that cause the brain to black out disturbing memories can cause the effect. (Related: "Beyond the Brain" in National Geographic magazine.)

Incomplete Picture

Reporting this week in the online edition of the journal Proceedings of the National Academy of Sciences, Maguire and colleagues examined patients who were "profoundly amnesic."

These patients were unable to acquire any new memories.

Several of the amnesiacs did have some past memories, but only of events that occurred 10 or even 20 years before the onset of their illness. Many had no detailed memories of anything that had ever happened in their lives.

The researchers asked the amnesiacs to imagine scenarios such as lying on a sandy beach and then to describe what the experience would be like—what they would see, hear, and smell.

But the patients could describe only fragmented scenes.

"They described many of the elements that would characterize the experience," Maguire said. "But they couldn't put them into a spatial context—they couldn't organize them into the location of that scenario."

"They would know there should be a sea, that there would be sand, but in the way they described it, they'd say, I just can't visualize the whole scene as you'd like," she added.

Without an environment or location to house a scene, amnesiacs may be unable to recreate or imagine normal experiences.

"If you think about memories, they are always somewhere, because things happen somewhere," Maguire explained. "So spatial context is very important for our experiences."

Placing a Memory

Scientists believe that the brain recalls past events by meticulously reconstructing the individual cues of an experience—the people, objects, and other aspects that composed the scene.

This process is thought to occur in a region of the brain known as the hippocampus, which was damaged in the amnesiac patients studied. (Related: "First Ever Brain 'Atlas' Completed" [September 26, 2006].)

The new study implies that similar processes in the hippocampus are also used to imagine future events, suggesting that memory and imagination are two sides of the same coin.

The hippocampus may provide the spatial context that binds and blends the people, objects, and other aspects of a memory—or an imagined event.

"Maybe the hippocampus," Maguire said, "is the basic scaffold around which memories are hung."

 

More professional football players are turning up with irreversible brain disorders. Are concussions to blame?

By Brett Zarda | August 2007 From Popular Science

 

Andre Waters, 44, shot himself in the head after bouts with depression. Terry Long drank a bottle of antifreeze at 45. Thirty-six-year-old Justin Strzelczyk heard voices and died in a crash while fleeing police. All ex–NFL players, all dead before their 46th birthday, and according to autopsies performed by physician Bennet Omalu, all with signs of brain damage.

Omalu, a former neuropathologist at the University of Pittsburgh School of Medicine, believes he's the first to pinpoint forensic evidence of a condition he has dubbed football-induced chronic traumatic encephalopathy (CTE), a variation of "boxer's dementia." Symptoms include confusion, mood disorders, slurred speech and memory loss. On the eve of football season, Omalu, along with a growing number of clinicians, argues that other players are at risk.

Now chief medical examiner for San Joaquin County in California, Omalu discovered abnormal proteins in each player's brain similar to those found in 90-year-old dementia patients. He believes that scores of players have analogous damage, but proving it requires postmortem brain sectioning. "These are not the first football players to develop dementia, become destitute, and suffer from depression," he says. "The novelty is that for the first time, we have direct, indisputable tissue evidence."

The NFL, however, isn't convinced. "No one is dismissing the work, but there are numerous inconsistencies and inaccuracies," says physician Ira Casson, co-chairman of the NFL's Mild Traumatic Brain Injury (MTBI) committee. "We refuse to jump on the bandwagon with the first report."

Casson disagrees that the pathology is consistent with boxer's dementia. Omalu concedes that components of boxer's CTE are not evident, but notes that different impacts will yield different pathologies.

Kevin Guskiewicz, the research director at the Center for the Study of Retired Athletes, a frequent critic of the MTBI committee, says the NFL should consider evidence beyond brain slices. Surveying retired players, Guskiewicz found a three-fold increase in clinical-depression rates after three or more concussions. In June he presented his findings at the first-ever "concussion summit" in Chicago, a gathering of more than 250 clinicians, player representatives, and team doctors and trainers convened by NFL commissioner Roger Goodell to discuss traumatic head injuries. Casson dismissed Guskiewicz's results as well, saying the study relied too heavily on anecdotal information. "The data is there," Guskiewicz counters. "Now, hopefully, physicians and trainers will put it to good use."

The NFL has come under mounting pressure to step up the care of its players. Most recently, a congressional subcommittee threatened to enact legislation that would force the league to improve its player-disability plan. Slowly, the NFL is beginning to make changes. As of this season, all players must undergo neuropsychological testing, and the MTBI committee is initiating a study to monitor brain function in retired players. The league has also implemented a new medical plan to cover players diagnosed with dementia. (It has accepted 50 of 104 applications to date.)

Meanwhile, the New Hampshire–based company Simbex is developing technology that could help prevent CTE altogether. It makes sensor-embedded telemetry helmets that can gauge in real time a concussive-level impact and notify personnel on the sidelines. In addition to helping staff decide when to bench a player, the technology is enabling researchers to better understand the biomechanical causes of head trauma, which in turn could lead to better headgear. Seven universities and five high schools now require players to wear the helmets. The NFL is considering the technology but has no firm plans to adopt it.

Guskiewicz, for one, insists that the NFL needs to do more. "Is it smarter to assume the risk is there, until proven otherwise, and treat the players more cautiously," he asks, "or should we assume it's not there and risk the chance?"

 

As Diet Ideas Abound, Is Willpower Obsolete?
By BARRON H. LERNER, M.D.
Published: July 10, 2007

When I was growing up, the word “willpower” was used a lot. If only one was strong enough to resist sweets, according to logic of the time, one could stay thin.

Yet today, based on a series of scientific discoveries, the importance of willpower in promoting weight loss is becoming an obsolete notion. Is it worth saving?

The concept of willpower came less from scientific data than from Christian teachings about the dangers of temptation. Gluttony, after all, was one of the seven deadly sins, up there with pride, greed, extravagance, envy, wrath and sloth.

The late 19th century was perhaps the heyday of the revolt against what John C. Burnham, a historian at Ohio State University, calls “bad habits.” Groups like the Salvation Army and the Women’s Christian Temperance Union urged sinners to stop drinking, gambling and smoking.

Comparable sentiments characterized writings about obesity. In 1946, Wilson G. Smillie, a public health professor at Cornell, wrote that the physician should appeal to the obese patient’s “ability to manifest self-control.” Weight-loss programs like Overeaters Anonymous and Weight Watchers have reflected this philosophy.

Similarly, many physicians have also discouraged surgical procedures like stomach stapling or shortening of the intestines, not only because of their risks but also because they were somehow seen as quick fixes for lazy patients who do not stick to their diets.

But as critics have pointed out, while willpower can work, it usually does not. A study published in The Journal of the American Medical Association in 2005 found that regardless of the diet attempted, patients lost an average of only 5 percent of their baseline weight after one year. And dropout rates exceeded 40 percent. [A newer study is reported on this page today, in Vital Signs.]

As a result, strategies for promoting weight loss have recently begun to shift from a focus on individual behaviors to a public health approach.

As the late Dr. Donald H. Gemson of the Mailman School of Public Health at Columbia once put it, “the causes of the obesity epidemic are environmental, and the answers will be as well.” Rather than simply urging people to eat better and exercise more, experts like Dr. Gemson have increasingly argued that society has to facilitate such changes by reducing the availability of high-calorie foods, advertisements of junk food to children and reliance on automobiles, while increasing access to healthy foods and exercising.

The environmental theory of obesity is prompting governmental interventions, like New York City’s ban on most trans fats in restaurant food. And environmental strategies have successfully been used in other areas that formerly relied on moral suasion. For example, taxes on cigarettes have contributed greatly to lowered smoking rates. Legislatures have enacted laws making restaurants liable if they permit drunk patrons to drive home.

So will people necessarily lose weight if society actively discourages fattening foods? Maybe not. Consider the genetic hypothesis, the latest reassessment of the obesity problem.

Research suggesting a strong hereditary predisposition to obesity goes back several decades, but several recent findings have put this theory into the forefront. In 1994, for example, Jeffrey M. Friedman, a molecular geneticist at Rockefeller University, discovered the appetite-regulating hormone leptin. Dr. Friedman believes that people’s appetites are largely controlled by genetics, which causes them to have different “set points” at different times in their lives.

A study in The Journal of the American Medical Association in May suggested another way in which genetics might affect changes in weight. Researchers from Children’s Hospital in Boston reported that differences in how young adults secrete the hormone insulin determine how well they respond to various dietary interventions.

So maybe it is time for health professionals to stop reflexively assuming that personal sacrifice will lead to weight loss. But this will not be easy.

For one thing, there certainly are success stories of people who have dropped dozens of pounds by drastically altering their lifestyles. Moreover, watching one’s diet can have beneficial health effects beyond losing weight.

And I just cannot conceive of a session with an overweight patient that does not involve a discussion of being careful at holiday meals, controlling portion size, avoiding bedtime snacks and trying to exercise three times a week. Somehow it still seems to me that part of a doctor’s job is to push patients to try harder. Just call me old-fashioned.

Barron H. Lerner teaches medicine and public health at Columbia University Medical Center.