Category: Memory

People who read vivid print advertisements for fictitious products actually come to believe they've tried those products, according to a new study in the Journal of Consumer Research.

"Exposing consumers to imagery-evoking advertising increases the likelihood that a consumer mistakenly believes he/she has experienced the advertised product, and subsequently produces attitudes that are as strong as attitudes based on genuine product experience," write authors Priyali Rajagopal (Southern Methodist University) and Nicole Montgomery (College of William and Mary).

In one study, the researchers showed participants different types of ads for a fictitious product: Orville Redenbacher's Gourmet Fresh microwave popcorn. Other participants ate what they believed to be Orville Redenbacher's Gourmet Fresh microwave popcorn, even though it was another Redenbacher product. One week after the study, all the participants were asked to report their attitudes toward the product and how confident they were in their attitudes.

"Students who saw the low imagery ad that described the attributes of the popcorn were unlikely to report having tried the popcorn, and they exhibited less favorable and less confident attitudes toward the popcorn than the other students," the authors write.

People who had seen the high imagery ads were just as likely as participants who actually ate the popcorn to report that they had tried the product. They were also as confident in their memories of trying the product as participants who actually sampled it. "This suggests that viewing the vivid advertisement created a false memory of eating the popcorn, despite the fact that trying the fictitious product would have been impossible," the authors write.

The authors found that decreasing brand familiarity and shortening the time between viewing the ad and reporting evaluations reduced the false memories in participants. For example, when the fictitious brand was Pop Joy's Gourmet Fresh instead of the more familiar Orville Redenbacher's, participants were less likely to report false memories of trying it.

"Consumers need to be vigilant while processing high-imagery advertisements because vivid ads can create false memories of product experience," the authors conclude.

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Journal Reference:

1. Priyali Rajagopal and Nicole Votolato Montgomery. I Imagine, I Experience, I Like: The False Experience Effect. Journal of Consumer Research, October 2011 DOI: 10.1086/660165

 Several years ago, Suparna Rajaram noticed a strange sort of contagion in a couple she was close to. One partner acquired dementia — and the other lost the nourishing pleasures of joint reminiscence. "When the other person cannot validate shared memories," said Rajaram, "they are both robbed of the past."

From this observation came a keen and enduring interest in the social nature of memory, an area of scholarship occupied mostly by philosophers, sociologists, and historians — and notably unattended to until recently by cognitive psychologists.

So Rajaram, a psychology professor at Stony Brook University, began to specialize in "collaborative memory" — or how people learn and remember in groups. People generally believe that collaboration helps memory — but does it always? "How is memory shaped by being experienced in a social context?" These are the questions Rajaram investigates in the lab — and addresses in a new paper published in Current Directions in Psychological Science, a journal of the Association for Psychological Science.

Some findings in the field of collaborative memory research have been counter intuitive. For one, collaboration can hurt memory. Some studies have compared the recall of items on lists by "collaborative groups," or those who study together, and "nominal groups," in which individuals work alone and the results are collated. The collaborative groups remembered more items than any single person would have done alone. But they also remembered fewer than the nominal groups did by totaling the efforts of its solitary workers. In other words, the collaborators' whole was less than the sum of its parts.

This so-called "collaborative inhibition" affects recall for all sorts of things, from word pairs to emotionally laden events; it affects strangers or spouses, children or adults. It is, in scientific lingo, "robust."

What explains this? One dynamic is "retrieval disruption": Each person remembers in his or her own way, and compelled to listen to others, can't use those strategies effectively. Sometimes that effect fades. Sometimes it squashes the memories for good, causing "post collaborative forgetting." Then there's "social contagion" of errors, wherein a group member can implant erroneous recollections in another's memory.

On the other hand, collaborative learning helps — which is why people hold it in high esteem. Individuals recall different information or events; after time, they can get together, contribute their bits, and reeducate each others' memories and expand the group's recall, mitigating the costs of collaboration. People can also correct each other's erroneous memories, a process Rajaram and her colleagues call "error pruning." Or they can "cross-cue" — bring up recollections that jog memories others have forgotten.

Rajaram's work involves small groups in the controlled laboratory environment. Yet, like others in her field, she believes it can inform the understanding of the wider "networks in which social memory phenomena are occurring" — classrooms, institutions, communities, subcultures, or nations.

"If a small group can reshape memories, we see how individuals come to hold certain viewpoints or perspectives," she says. "That can serve as a model for how collective identities and histories are shaped."

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Journal Reference:

1. S. Rajaram. Collaboration Both Hurts and Helps Memory: A Cognitive Perspective. Current Directions in Psychological Science, 2011; 20 (2): 76 DOI: 10.1177/0963721411403251

 Lapses in memory occur more frequently with age, yet the reasons for this increasing forgetfulness have not always been clear. According to new research from Concordia University, older individuals have reduced learning and memory because their minds tend to be cluttered with irrelevant information when performing tasks.

Published in The Quarterly Journal of Experimental Psychology, these findings offer new insights into why aging is associated with a decline in memory and may lead to practical solutions.

"The first step of our study was to test the working memory of a younger and older population and compare the results," says Mervin Blair, first author and a PhD student in Concordia's Department of Psychology and a member at the Centre for Research in Human Development. "In our study, working memory refers to the ability of both retaining and processing information."

Some 60 participants took part in the study: half were an average of 23 years old, while the other half was about 67 years old. Each participant was asked to perform a working memory task, which included recalling and processing different pieces of information.

"Overall, we showed that our older participants had reduced working memory compared to our younger participants," says Blair. "Younger adults were better than the older adults at recalling and processing information."

"Our study was novel because we looked at how the ability to recall and process information at the same time changes as people get older," adds Karen Li, senior author and a professor in Concordia's Department of Psychology and a member of the Centre for Research in Human Development.

Older people don't purge irrelevant info

The next step was to determine if there was a timeframe when the ability to delete irrelevant information, known as inhibition deletion, changed. This was measured using a sequential memory task . Images were displayed in a random order and participants were required to respond to each image in a pre-learned manner. Once again, the youngsters outperformed their older counterparts. "The older adults had poor inhibition, repeatedly responding to previously relevant images," says Blair.

Analyses were conducted to determine the relationship between the ability to clear irrelevant information and working memory ability. "Poor inhibition predicted a decline in the recall component of working memory and it also predicted decline in the processing component of working memory," says Blair. "Basically, older adults are less able to keep irrelevant information out of their consciousness, which then impacts on other mental abilities."

For those who are having trouble remembering, Blair suggests that focusing and reducing mental clutter may help. "Reduce clutter, if you don't, you may not get anything done."

Keeping a mind clutter-free can be more difficult as people age, especially during periods of stress when people focus on stressors, yet Blair says relaxation exercises can help de-clutter the brain. What's more, the brain continues to function optimally into old age when it is mentally stimulated by learning a new language, playing an instrument, completing crossword puzzles, keeping an active social life and exercising.

The study was authored by Mervin Blair, Kiran Vadaga, Joni Shuchat and Karen Li of Concordia University.

This work was supported by funds from the Natural Sciences and Engineering Research Council of Canada.

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Journal Reference:

1. Mervin Blair, Kiran Vadaga, Joni Shuchat, Karen Li. The role of age and inhibitory efficiency in working memory processing and storage components. The Quarterly Journal of Experimental Psychology, 2010; 99999 (1): 1 DOI: 10.1080/17470218.2010.540670

University of Utah psychologists have learned why many people experience "inattention blindness" — the phenomenon that leaves drivers on cell phones prone to traffic accidents and makes a gorilla invisible to viewers of a famous video.

The answer: People who fail to see something right in front of them while they are focusing on something else have lower "working memory capacity" — a measure of "attentional control," or the ability to focus attention when and where needed, and on more than one thing at a time.

"Because people are different in how well they can focus their attention, this may influence whether you'll see something you're not expecting, in this case, a person in a gorilla suit walking across the computer screen," says the study's first author, Janelle Seegmiller, a psychology doctoral student.

The study — explaining why some people are susceptible to inattention blindness and others are not — will be published in the May issue of The Journal of Experimental Psychology: Learning, Memory and Cognition.

Seegmiller conducted the research with two psychology faculty members — Jason Watson, an assistant professor, and David Strayer, a professor and leader of several studies about cell phone use and distracted driving.

"We found that people who notice the gorilla are better able to focus attention," says Watson, also an assistant investigator with the university's Brain Institute.

'The Invisible Gorilla' Test for Inattention Blindness

The new study used a video made famous by earlier "inattention blindness" research featured in the 2010 book "The Invisible Gorilla," by Christopher Chabris, a psychologist at Union College in Schenectady, N.Y., and Daniel Simons, a psychologist at the University of Illinois at Urbana-Champaign.

The video depicts six actors passing a basketball. Viewers are asked to count the number of passes. Many people are so intent on counting that they fail to see a person in a gorilla suit stroll across the scene, stop briefly to thump their chest, and then walk off.

Seegmiller, Watson and Strayer did a new version of the older experiments, designed to determine the reason some people see the gorilla and others miss it.

Why are the results important?

"You can imagine that if you're driving and road conditions aren't very good, unexpected things can happen, and individuals with better control over attention would be more likely to notice those unexpected events without having to be explicitly told to watch for them," Seegmiller says.

Watson adds: "The potential implications are that if we are all paying attention as we are driving, some individuals may have enough extra flexibility in their attention to notice distractions that could cause accidents. That doesn't mean people ought to be self-distracting by talking on a cell phone while driving — even if they have better control over their attention. Our prior research has shown that very few individuals [only 2.5 percent] are capable of handling driving and talking on a cell phone without impairment. "

Strayer has conducted studies showing that inattention blindness explains why motorists can fail to see something right in front of them — like a stop light turning green — because they are distracted by the conversation, and how motorists using cell phones impede traffic and increase their risk of traffic accidents.

Linking Working Memory to Inattention Blindness

A key question in the study was whether people with a high working memory capacity are less likely to see a distraction because they focus intently on the task at hand — a possibility suggested by some earlier research — or if they are more likely to see a distraction because they are better able to shift their attention when needed.

The new study indicates the latter is true.

"We may be the first researchers to offer an explanation for why some people notice the gorilla and some people don't," Watson says.

Working memory capacity "is how much you can process in your working memory at once," Seegmiller says. "Working memory is the stuff you are dealing with right at that moment, like trying to solve a math problem or remember your grocery list. It's not long-term memory like remembering facts, dates and stuff you learned in school."

The researchers studied working memory capacity because it "is a way that we measure how some people can be better than other people at focusing their attention on what they're supposed to," she adds.

The Utah study began with 306 psychology students who were tested with the gorilla video, but about one-third then were excluded because they had prior knowledge of the video. That left 197 students, ages 18 to 35, whose test results were analyzed.

First, the psychologists measured working memory capacity using what is known as an "operation span test." Participants were given a set of math problems, each one of which was followed by a letter, such as "Is 8 divided by 4, then plus 3 equal to 4? A."

Each participant was given a total of 75 of these equation-letter combinations, in sets of three to seven. For example, if a set of five equations ended with the letters A, C, D, G, P, the participant got five points for remembering ACDGP in that order. After each set of equations and letters, participants were asked to recall all the letters of each set. A few participants scored a perfect 75 score.

Participants had to get 80 percent of the math equations right to be included in the analysis. That was to ensure they focused on solving the math problems and not just on remembering the letters after the equations.

Next, the participants watched the 24-second Chabris-Simons gorilla video, which had two, three-member basketball teams (black shirts and white shirts) passing balls. Participants were asked to count bounce passes and aerial passes by the black team. Then they were asked for the two pass counts and whether they noticed anything unusual.

To remove a potential bias in the study, the researchers had to make sure the people who noticed the gorilla also were counting basketball passes; otherwise, people who weren't counting passes would be more likely to notice the distraction. So only video viewers who were at least 80 percent accurate in counting passes were analyzed.

The Utah psychologists got results quite similar to those found by Simons and Chabris in their original study in 1999: of participants who were acceptably accurate in counting passes, 58 percent in the new study noticed the gorilla and 42 percent did not.

But the Utah study went further: Again analyzing only accurate pass counters, the gorilla was noticed by 67 percent of those with high working memory capacity but only by 36 percent of those with low working memory capacity.

In other words, "if you are on task and counting passes correctly, and you're good at paying attention, you are twice as likely to notice the gorilla compared with people who are not as good at paying attention," Watson says. "People who notice the gorilla are better able to focus their attention. They have a flexible focus in some sense."

Put another way, they are better at multitasking.

Future studies should look for other possible explanations of why some people suffer inattention blindness and others do not, including differences in the speeds at which our brains process information, and differences in personality types, the Utah psychologists say.

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Journal Reference:

1. Janelle K. Seegmiller, Jason M. Watson, David L. Strayer. Individual differences in susceptibility to inattentional blindness.. Journal of Experimental Psychology: Learning, Memory, and Cognition, 2011; DOI: 10.1037/a0022474

Using advanced imaging technology, scientists from the Florida campus of The Scripps Research Institute have identified a change in chemical influx into a specific set of neurons in the common fruit fly that is fundamental to long-term memory.

The study was published in the April 13, 2011 issue of The Journal of Neuroscience.

"In studying fruit flies' learning and long-term memory storage, we observed an increase in calcium influx into a specific set of brain neurons in normal fruit flies that was absent in 26 different mutants known to impair long-term memory,," said Ron Davis, chair of the Scripps Research Department of Neuroscience, who led the study. "This logical conclusion is that this increase, which we call a memory trace, is a signature component of long-term memory."

The memory trace in question is an increased influx of calcium into a set of neurons after long-term memory forms in a part of the insect brain known as mushroom bodies, a pair of oversized lobes known to mediate learning and memory, particularly the memories of smell. They have been compared to the hippocampus, a site of memory formation in humans.

Increases in calcium influx also occur with learning in other animal models, Davis said, and it seems highly likely a similar correlation exists in humans.

Measuring Memory Traces

To measure the changes in the Drosophila neurons, Davis and his colleagues used functional optical imaging, an advanced technology that his laboratory helped pioneer for the study of learning and memory. Using protein sensors that become fluorescent when calcium levels are increased, the team was able to highlight changes in the levels of calcium influx into the mushroom body neurons in response to odor learning. These observed memory traces occur in parallel with behavioral changes.

Interestingly, these memory traces occur only with spaced conditioning — where the insects receive multiple episodes of learning but with periods of rest between each episode. Spaced conditioning is required for long-term memories to form.

In an earlier study last December, also published in The Journal of Neuroscience, Davis found not only that fruit flies receiving spaced conditioning exhibited a long-term memory trace, but also that their memories lasted between four and seven days. In flies that were given a single episode of learning, memory formation lasted only a day and the long-term memory trace failed to form. These two studies are the newest in a series of six studies on the topic, including those published in the journal Neuron in 2004 and 2006, Cell in 2005, and Nature Neuroscience in 2008. Davis reviewed all of his studies of memory traces in the most recent issue of Neuron.

"The phenomenon of spaced conditioning is conserved across all species," Davis said. "No one really knows why it's important to long-term memory formation but there appears to be something magical about that rest period during learning."

The study was supported by the National Institutes of Health.

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Journal Reference:

1. David-Benjamin G. Akalal, Dinghui Yu and Ronald L. Davis. The Long-Term Memory Trace Formed in the Drosophila α/β Mushroom Body Neurons Is Abolished in Long-Term Memory Mutants. The Journal of Neuroscience, 13 April 2011, 31(15):5643-5647 DOI: 10.1523/JNEUROSCI.3190-10.2011

— John Gunstad, an associate professor in Kent State University's Department of Psychology, and a team of researchers have discovered a link between weight loss and improved memory and concentration. The study shows that bariatric surgery patients exhibited improved memory function 12 weeks after their operations.

The findings will be published in an upcoming issue of Surgery for Obesity and Related Diseases, the Official Journal of the American Society for Metabolic and Bariatric Surgery.

"The initial idea came from our clinical work," Gunstad said. "I was working at Brown Medical School in Rhode Island at the time and had the chance to work with a large number of people who were looking to lose weight through either behavioral means or weight loss surgery."

Gunstad said he kept noticing that these patients would make similar mistakes. "As a neuropsychologist who is focused on how the brain functions, I look for these little mental errors all the time," Gunstad explained.

The research team studied 150 participants (109 bariatric surgery patients and 41 obese control subjects) at Cornell Medical College and Weill Columbia University Medical Center, both in New York City, and the Neuropsychiatric Research Institute in Fargo, N.D. Many bariatric surgery patients exhibited impaired performance on cognitive testing, according to the study's report.

The researchers discovered that bariatric surgery patients demonstrated improved memory and concentration 12 weeks after surgery, improving from the slightly impaired range to the normal range.

"The primary motivation for looking at surgery patients is that we know they lose a lot of weight in a short amount of time, so it was a good group to study," Gunstad said. "This is the first evidence to show that by going through this surgery, individuals might improve their memory, concentration and problem solving."

Gunstad thinks the study is reason for optimism. "One of the things about obesity, relative to other medical conditions, is that something can be done to fix it," Gunstad said. "Our thought was, if some of these effects are reversible, then we're really on to something — that it might be an opportunity for individuals who have memory or concentration problems to make those things better in a short amount of time. And that's what we found."

The team is following study participants for two years. They tested subjects before surgery, 12 weeks after surgery and one year after surgery, and will also test at the two-year mark.

Gunstad was the principal investigator for the team, which included Gladys Strain, Ph.D., of Cornell Medical College in New York City; Michael Devlin, M.D., of Weill Columbia University Medical Center in New York City; Rena Wing, Ph.D., and Ronald Cohen, Ph.D., of the Warren Albert Medical School of Brown University in Providence, R.I.; Robert Paul, Ph.D., of the University of Missouri-St. Louis in St. Louis, Miss.; and Ross Crosby, Ph.D., and James Mitchell, M.D., of the Neuropsychiatric Research Institute in Fargo, N.D.

Gunstad wasn't surprised by the study's findings. "A lot of the factors that come with obesity — things such as high blood pressure, type 2 diabetes and sleep apnea — that might damage the brain are somewhat reversible," Gunstad said. "As those problems go away, memory function gets better."

The team's next project will examine whether people who experience behavioral weight loss see the same effects as those who have had bariatric surgery. Gunstad said he expects to see similar results.

"One of the things we know is that as individuals become more cardiovascular fit and their heart health gets better, their brain health also improves," Gunstad added. "Even if we take young adults and put them through an exercise program, their memory and their concentration get better by the end of the program."

The cost for the research project was approximately $1.5 million, and was funded by a grant from the National Institute of Health.

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Journal Reference:

1. John Gunstad et al. Improved memory function 12 weeks after bariatric surgery. Journal of the American Society for Metabolic and Bariatric Surgery, 2010 DOI: 10.1016/j.soard.2010.09.015

Most people have had trouble remembering something they just heard. Now, a University of Missouri researcher found that forgetfulness may have something to do with being in a good mood. Elizabeth Martin, a doctoral student of psychology in the College of Arts and Science, has found that being in a good mood decreases your working memory capacity.

"Working memory, for example, is the ability to recall items in a conversation as you are having it," Martin said. "This explains why you might not be able to remember a phone number you get at a party when you are having a good time. This research is the first to show that positive mood can negatively impact working memory storage capacity. This shows that although systems in the brain are connected, it is possible to affect one process but not others."

Researchers gauged study participants' mood before and after showing them a video clip. Some participants were shown a segment of a stand-up comedy routine, while others watched an instructional video on how to install flooring. Following the videos, those that viewed the comedy routine were in significantly better moods after viewing the video, while the mood of those that viewed the flooring video had not changed.

After watching the videos, both groups completed a memory test. This test provides several numbers to a participant through headphones at a rate of four numbers per second. After the recording stopped, participants were asked to recall the last six numbers in order. Those that watched the comedy routine and were in a better mood performed significantly worse on the task.

"While working memory storage is decreased, being in a good mood is not all bad," Martin said. "Being in a good mood has been shown to increase creative problem-solving skills and other aspects of thinking." Martin said future research should analyze the impact of mood on working memory storage capacity in real life situations, such as a classroom setting.

The study was published earlier this year in the journal Cognition and Emotion. The research was funded by grants awarded to research advisor Associate Professor John Kerns from the National Institute of Mental Health, the National Institute of Drug Abuse and a grant from the MU Research Board.

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Journal Reference:

1. Elizabeth Martin, John Kerns. The influence of positive mood on different aspects of cognitive control. Cognition & Emotion, 2011; 25 (2): 265 DOI: 10.1080/02699931.2010.491652

 Researchers from Rice University and Georgia Institute of Technology have found support for the theory that the brain has three concentric layers of working memory where it stores readily available items. Memory researchers have long debated whether there are two or three layers and what the capacity and function of each layer is.

In a paper in the March issue of the Journal of Cognitive Psychology, researchers found that short-term memory is made up of three areas: a core focusing on one active item, a surrounding area holding at least three more active items, and a wider region containing passive items that have been tagged for later retrieval or "put on the back burner." But more importantly, they found that the core region, called the focus of attention, has three roles — not two as proposed by previous researchers. First, this core focus directs attention to the correct item, which is affected by predictability of input pattern. Then it retrieves the item and subsequently, when needed, updates it.

The researchers, Chandramallika Basak of Rice University and Paul Verhaeghen of Georgia Tech, used simple memory tasks involving colors and shapes on a computer screen to determine the three distinct layers of memory. They also determined the roles of attention focus by exploring the process of switching items in and out of the focus of attention.

In their previous studies, Basak and Verhaeghen discovered that response time for switching in and out of the core focus is not affected by the number of items stored when the items are input in a predictable pattern.

In this study of 49 participants across two experiments, the researchers found that when no pattern exists, all participants increased their response time by an average of 240 milliseconds per item as more items are stored. This implies that the area outside the focus has to be searched when there is no pattern, even before the item can be retrieved.

However, as evidenced by the previous studies, when participants were given 10 hours of practice in a memory task with a predictable pattern, all of them could enhance the focus of attention to store four items in the focus core. But this focus does not expand when the memory task has no pattern.

"Predictability can free up resources so a person can effectively multitask," said Basak, assistant professor of psychology at Rice and lead author of the study. "When you do the same sequence over and over again, your memory can be partially automatized so you have the ability to do another task concurrently."

This comes naturally, Basak said. For instance, as you drive the usual route to your regular grocery store, you might also be thinking about what to fix for dinner and making a grocery list. That same secondary task — the grocery list — becomes more of a challenge when driving to a different grocery store using an unfamiliar route.

Another facet of the study showed that the third level of memory — the region containing passive items — is not only separate from the other two areas of active storage but has a firewall between them. The number of passive items does not influence either response time or accuracy for recalling active items.

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Journal Reference:

1. Chandramallika Basak, Paul Verhaeghen. Three layers of working memory: Focus-switch costs and retrieval dynamics as revealed by the N-count task. Journal of Cognitive Psychology, 2011; 23 (2): 204 DOI: 10.1080/20445911.2011.481621

 — Northwestern Medicine researchers for the first time have transformed a human embryonic stem cell into a critical type of neuron that dies early in Alzheimer's disease and is a major cause of memory loss.

This new ability to reprogram stem cells and grow a limitless supply of the human neurons will enable a rapid wave of drug testing for Alzheimer's disease, allow researchers to study why the neurons die and could potentially lead to transplanting the new neurons into people with Alzheimer's.

The paper will be published March 4 in the journal Stem Cells.

These critical neurons, called basal forebrain cholinergic neurons, help the hippocampus retrieve memories in the brain. In early Alzheimer's, the ability to retrieve memories is lost, not the memories themselves. There is a relatively small population of these neurons in the brain, and their loss has a swift and devastating effect on the ability to remember.

"Now that we have learned how to make these cells, we can study them in a tissue culture dish and figure out what we can do to prevent them from dying," said senior study author Jack Kessler, M.D., chair of neurology and the Davee Professor of Stem Cell Biology at Northwestern University Feinberg School of Medicine and a physician at Northwestern Memorial Hospital.

The lead author of the paper is Christopher Bissonnette, a former doctoral student in neurology who labored for six years in Kessler's lab to crack the genetic code of the stem cells to produce the neurons. His research was motivated by his grandfather's death from Alzheimer's.

"This technique to produce the neurons allows for an almost infinite number of these cells to be grown in labs, allowing other scientists the ability to study why this one population of cells selectively dies in Alzheimer's disease," Bissonnette said.

The ability to make the cells also means researchers can quickly test thousands of different drugs to see which ones may keep the cells alive when they are in a challenging environment. This rapid testing technique is called high-throughput screening.

Kessler and Bissonnette demonstrated the newly produced neurons work just like the originals. They transplanted the new neurons into the hippocampus of mice and showed the neurons functioned normally. The neurons produced axons, or connecting fibers, to the hippocampus and pumped out acetylcholine, a chemical needed by the hippocampus to retrieve memories from other parts of the brain.

Human skin cells transformed into stem cells and then neurons

In new, unpublished research, Northwestern Medicine scientists also have discovered a second novel way to make the neurons. They made human embryonic stem cells (called induced pluripotent stem cells) from human skin cells and then transformed these into the neurons.

Scientists made these stem cells and neurons from skin cells of three groups of people: Alzheimer's patients, healthy patients with no family history of Alzheimer's, and healthy patients with an increased likelihood of developing the disease due to a family history of Alzheimer's because of genetic mutations or unknown reasons.

"This gives us a new way to study diseased human Alzheimer's cells," Kessler said. "These are real people with real disease. That's why it's exciting."

Researcher motivated by his grandfather's Alzheimer's disease

Bissonnette's persistence in the face of often frustrating research was fueled by the childhood memory of watching his grandfather die from Alzheimer's.

"I watched the disease slowly and relentlessly destroy his memory and individuality, and I was powerless to help him," Bissonnette recalled. "That drove me to become a scientist. I wanted to discover new treatments to reverse the damage caused by Alzheimer's disease."

"My goal was to make human stem cells become new healthy replacement cells so that they could one day be transplanted into a patient's brain, helping their memory function again," he said.

Bissonnette had to grow and test millions of cells to figure out how to turn on the exact sequence of genes to transform the stem cell into the cholinergic neuron.

"A stem cell has the potential to become virtually any cell in the body, from a heart cell to a layer of skin," he explained. "Its development is caused by a cascade of things that slowly bump it into a final cell type."

But it wasn't enough just to develop the neurons. Bissonnette then had to learn how to stabilize them so they lived for at least 20 days in order to prove they were the correct cells.

"Since this was brand new research, people didn't know what kind of tissue culture mature human neurons would like to live in," he said. "Once we figured it out, they could live indefinitely."

The research was supported by the National Institutes of Health.

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Journal Reference:

1. Christopher John Bissonnette, Ljuba Lyass, Bula J Bhattacharyya, Abdelhak Belmadani, Richard J Miller, John A Kessler. The Controlled Generation of Functional Basal Forebrain Cholinergic Neurons from Human Embryonic Stem Cells. Stem Cells, 2011; DOI: 10.1002/stem.626