Science Daily (Mar. 1, 2012) — If someone has trouble remembering where the car keys or the cheese grater are, new research shows that a memory training strategy can help. Memory training can even re-engage the hippocampus, part of the brain critical for memory formation, the results suggest.
Researchers at Emory University School of Medicine and Atlanta Veterans Affairs Medical Center have been investigating memory-building strategies for people with MCI (mild cognitive impairment). The techniques used in the study were known to be effective for healthy people, but it has been uncertain how they could affect brain function in people with MCI.
The results are published online in the journal Hippocampus.
"Our results suggest that these strategies can help patients remember specific information, such as the locations of objects, " says lead author Benjamin Hampstead, PhD, assistant professor of rehabilitation medicine at Emory University School of Medicine. "This is the first randomized controlled trial to show that these techniques are not only effective in MCI patients, but that they can also re-engage the hippocampus, which is a brain region that is critical for forming new memories."
Hampstead is a clinical neuropsychologist at the Atlanta VA Rehabilitation, Research and Development Center of Excellence. Study co-authors included Krish Sathian, MD, PhD, professor of neurology, rehabilitation medicine, and psychology, and director of the Rehabilitation R&D Center of Excellence at the Atlanta VAMC; and Anthony Stringer, PhD, professor of rehabilitation medicine and psychology.
MCI is a diagnosis meant to identify those at increased risk of eventually converting to Alzheimer's disease. People with MCI have difficulty forming new memories but are still able to handle tasks of daily living. The difficulty learning and remembering new information is because of impaired function in parts of the brain including the hippocampus.
The study focused on how well participants could remember the locations of common household objects. The memory-building strategy involves three steps. First, participants focused on a feature of the room that stood out and was close to the object, then they learned a short explanation for why the object was in that location. Finally, they created a mental picture to tie the information together.
In several sessions, study participants were shown household objects one at a time, each object followed by its location in a computer-simulated room. An hour later, they were asked to identify the location of each object from among three choices.
After the first visit, participants returned to the laboratory for three training sessions. On a fifth visit two weeks later, they were evaluated on how well they could remember the objects' locations. A control group received the same amount of exposure to the objects and their locations, but was not given explicit training.
As expected, at the start of the study MCI patients had more difficulty remembering where objects were and showed less brain activity in the hippocampus (measured through functional magnetic resonance imaging) when compared with healthy people.
Both people with MCI and healthy controls benefited significantly more from using memory strategies than from mere exposure. In addition, MCI patients in the memory strategy-training group showed increased activity in the hippocampus as they learned and remembered the location of the objects. Participants in the training group showed increases in hippocampal activity, even when trying to remember the locations of new objects.
"This is an initial, albeit encouraging, step in determining methods that can help these patients function better in their everyday lives," says Stringer, who originally developed the strategies on which training in this study was based.
"These techniques may hold particular promise given that they appear to promote neuroplastic changes in key brain regions," Sathian says.
The Emory/VA team has also tested the effectiveness of the memory-building techniques for associating faces and names, in another set of studies. They are continuing the study of the memory-building techniques, with the aim of determining how long the benefits of training last, and whether participants can use the strategies independently outside the laboratory.
The research was supported by the Department of Veterans Affairs and the National Institute on Aging, part of the National Institutes of Health.
Thursday, March 29, 2012
New High Definition Fiber Tracking Reveals Damage Caused by Traumatic Brain Injury
Science Daily (Mar. 2, 2012) — A powerful new imaging technique called High Definition Fiber Tracking (HDFT) will allow doctors to clearly see for the first time neural connections broken by traumatic brain injury (TBI) and other neurological disorders, much like X-rays show a fractured bone, according to researchers from the University of Pittsburgh in a report published online in the Journal of Neurosurgery.
In the report, the researchers describe the case of a 32-year-old man who wasn't wearing a helmet when his all-terrain vehicle crashed. Initially, his CT scans showed bleeding and swelling on the right side of the brain, which controls left-sided body movement. A week later, while the man was still in a coma, a conventional MRI scan showed brain bruising and swelling in the same area. When he awoke three weeks later, the man couldn't move his left leg, arm and hand.
"There are about 1.7 million cases of TBI in the country each year, and all too often conventional scans show no injury or show improvement over time even though the patient continues to struggle," said co-senior author and UPMC neurosurgeon David O. Okonkwo, M.D., Ph.D., associate professor, Department of Neurological Surgery, Pitt School of Medicine. "Until now, we have had no objective way of identifying how the injury damaged the patient's brain tissue, predicting how the patient would fare, or planning rehabilitation to maximize the recovery."
HDFT might be able to provide those answers, said co-senior author Walter Schneider, Ph.D., professor of psychology at Pitt's Learning Research and Development Center (LRDC), who led the team that developed the technology. Data from sophisticated MRI scanners is processed through computer algorithms to reveal the wiring of the brain in vivid detail and to pinpoint breaks in the cables, called fiber tracts. Each tract contains millions of neuronal connections.
"In our experiments, HDFT has been able to identify disruptions in neural pathways with a clarity that no other method can see," Dr. Schneider said. "With it, we can virtually dissect 40 major fiber tracts in the brain to find damaged areas and quantify the proportion of fibers lost relative to the uninjured side of the brain or to the brains of healthy individuals. Now, we can clearly see breaks and identify which parts of the brain have lost connections."
HDFT scans of the study patient's brain were performed four and 10 months after he was injured; he also had another scan performed with current state-of the-art diffusion tensor imaging (DTI), an imaging modality that collects data points from 51 directions, while HDFT is based on data from 257 directions. For the latter, the injury site was compared to the healthy side of his brain, as well as to HDFT brain scans from six healthy individuals.
Only the HDFT scan identified a lesion in a motor fiber pathway of the brain that correlated with the patient's symptoms of left-sided weakness, including mostly intact fibers in the region controlling his left leg and extensive breaks in the region controlling his left hand. The patient eventually recovered movement in his left leg and arm by six months after the accident, but still could not use his wrist and fingers effectively 10 months later.
Memory loss, language problems, personality changes and other brain changes occur with TBI, which the researchers are exploring with HDFT in other research protocols.
UPMC neurosurgeons also have used the technology to supplement conventional imaging, noted Robert Friedlander, M.D., professor and chair, Department of Neurological Surgery, Pitt School of Medicine, and UPMC Endowed Professor of Neurosurgery and Neurobiology. He is not a member of this research study.
"I have used HDFT scans to map my approach to removing certain tumors and vascular abnormalities that lie in areas of the brain that cannot be reached without going through normal tissue," he said. "It shows me where significant functional pathways are relative to the lesion, so that I can make better decisions about which fiber tracts must be avoided and what might be an acceptable sacrifice to maintain the patient's best quality of life after surgery."
Dr. Okonkwo noted that the patient and his family were relieved to learn that there was evidence of brain damage to explain his ongoing difficulties. The team continues to evaluate and validate HDFT's utility as a brain imaging tool, so it is not yet routinely available.
"We have been wowed by the detailed, meaningful images we can get with this technology," Dr. Okonkwo said. "HDFT has the potential to be a game-changer in the way we handle TBI and other brain disorders."
Co-authors include lead author Samuel L. Shin, Ph.D., Allison J. Hricik, M.S., Megan Maserati, and Ava M. Puccio, Ph.D., all of the Department of Neurological Surgery; Timothy Verstynen, Ph.D., Sudhir Pathak, M.S., and Kevin Jarbo, all of LRDC; and Sue R. Beers, of the Department of Psychiatry, all of the University of Pittsburgh.
The study was funded by the Defense Advanced Research Projects Agency
In the report, the researchers describe the case of a 32-year-old man who wasn't wearing a helmet when his all-terrain vehicle crashed. Initially, his CT scans showed bleeding and swelling on the right side of the brain, which controls left-sided body movement. A week later, while the man was still in a coma, a conventional MRI scan showed brain bruising and swelling in the same area. When he awoke three weeks later, the man couldn't move his left leg, arm and hand.
"There are about 1.7 million cases of TBI in the country each year, and all too often conventional scans show no injury or show improvement over time even though the patient continues to struggle," said co-senior author and UPMC neurosurgeon David O. Okonkwo, M.D., Ph.D., associate professor, Department of Neurological Surgery, Pitt School of Medicine. "Until now, we have had no objective way of identifying how the injury damaged the patient's brain tissue, predicting how the patient would fare, or planning rehabilitation to maximize the recovery."
HDFT might be able to provide those answers, said co-senior author Walter Schneider, Ph.D., professor of psychology at Pitt's Learning Research and Development Center (LRDC), who led the team that developed the technology. Data from sophisticated MRI scanners is processed through computer algorithms to reveal the wiring of the brain in vivid detail and to pinpoint breaks in the cables, called fiber tracts. Each tract contains millions of neuronal connections.
"In our experiments, HDFT has been able to identify disruptions in neural pathways with a clarity that no other method can see," Dr. Schneider said. "With it, we can virtually dissect 40 major fiber tracts in the brain to find damaged areas and quantify the proportion of fibers lost relative to the uninjured side of the brain or to the brains of healthy individuals. Now, we can clearly see breaks and identify which parts of the brain have lost connections."
HDFT scans of the study patient's brain were performed four and 10 months after he was injured; he also had another scan performed with current state-of the-art diffusion tensor imaging (DTI), an imaging modality that collects data points from 51 directions, while HDFT is based on data from 257 directions. For the latter, the injury site was compared to the healthy side of his brain, as well as to HDFT brain scans from six healthy individuals.
Only the HDFT scan identified a lesion in a motor fiber pathway of the brain that correlated with the patient's symptoms of left-sided weakness, including mostly intact fibers in the region controlling his left leg and extensive breaks in the region controlling his left hand. The patient eventually recovered movement in his left leg and arm by six months after the accident, but still could not use his wrist and fingers effectively 10 months later.
Memory loss, language problems, personality changes and other brain changes occur with TBI, which the researchers are exploring with HDFT in other research protocols.
UPMC neurosurgeons also have used the technology to supplement conventional imaging, noted Robert Friedlander, M.D., professor and chair, Department of Neurological Surgery, Pitt School of Medicine, and UPMC Endowed Professor of Neurosurgery and Neurobiology. He is not a member of this research study.
"I have used HDFT scans to map my approach to removing certain tumors and vascular abnormalities that lie in areas of the brain that cannot be reached without going through normal tissue," he said. "It shows me where significant functional pathways are relative to the lesion, so that I can make better decisions about which fiber tracts must be avoided and what might be an acceptable sacrifice to maintain the patient's best quality of life after surgery."
Dr. Okonkwo noted that the patient and his family were relieved to learn that there was evidence of brain damage to explain his ongoing difficulties. The team continues to evaluate and validate HDFT's utility as a brain imaging tool, so it is not yet routinely available.
"We have been wowed by the detailed, meaningful images we can get with this technology," Dr. Okonkwo said. "HDFT has the potential to be a game-changer in the way we handle TBI and other brain disorders."
Co-authors include lead author Samuel L. Shin, Ph.D., Allison J. Hricik, M.S., Megan Maserati, and Ava M. Puccio, Ph.D., all of the Department of Neurological Surgery; Timothy Verstynen, Ph.D., Sudhir Pathak, M.S., and Kevin Jarbo, all of LRDC; and Sue R. Beers, of the Department of Psychiatry, all of the University of Pittsburgh.
The study was funded by the Defense Advanced Research Projects Agency
When One Side Does Not Know About the Other One: Specialization and Cooperation of the Brain Hemispheres
Science Daily (Mar. 2, 2012) — Whenever we are doing something, one of our brain hemispheres is more active than the other one. However, some tasks are only solvable with both sides working together. PD Dr. Martina Manns and Juliane Römling of the Ruhr-Universität Bochum are investigating, how such specializations and co-operations arise. Based on a pigeon-model, they are demonstrating for the first time in an experimental way, that the ability to combine complex impressions from both hemispheres, depends on environmental factors in the embryonic stage.
Within the egg bird embryos always turn their head in such a way that one eye is turned close to the eggshell, and the other one is covered by the body. This causes an asymmetrical light stimulation, which influences developmental processes in both brain halves. PD Dr. Manns uses this mechanism for her experiment. One group of embryos hatch in a lighted incubator, another one in complete darkness. Afterwards the scientists analyze the degree of interhemispheric communication in both groups. The results show that information exchange is impaired without light-stimulation. This research sheds light on the origin of communication processes in the brain. Developmental disorders like ADHD or autism are characterized by a deviating pattern between the two brain halves. Therefore, there is a possibility that the results may help to understand those disorders and give hints for new therapeutic approaches.
Classification of colour-pairs
To determine how efficient the animals are able to handle incoming information, Manns and Römling confront the animals with a task that can only be solved with both brain hemispheres working together. For that purpose, the two psychologists use colour-pairs of a transitive line(A>B>C>D>E) at which one of the elements is rewarded with food. First the pigeons have to learn to discriminate the combinations A/B and B/C with one eye, and C/D and D/E with the other one. Afterwards, they can use both eyes to decide between, for example, the colours B/D. However, only birds with embryonic light experience are able to solve this problem.
Within the egg bird embryos always turn their head in such a way that one eye is turned close to the eggshell, and the other one is covered by the body. This causes an asymmetrical light stimulation, which influences developmental processes in both brain halves. PD Dr. Manns uses this mechanism for her experiment. One group of embryos hatch in a lighted incubator, another one in complete darkness. Afterwards the scientists analyze the degree of interhemispheric communication in both groups. The results show that information exchange is impaired without light-stimulation. This research sheds light on the origin of communication processes in the brain. Developmental disorders like ADHD or autism are characterized by a deviating pattern between the two brain halves. Therefore, there is a possibility that the results may help to understand those disorders and give hints for new therapeutic approaches.
Classification of colour-pairs
To determine how efficient the animals are able to handle incoming information, Manns and Römling confront the animals with a task that can only be solved with both brain hemispheres working together. For that purpose, the two psychologists use colour-pairs of a transitive line(A>B>C>D>E) at which one of the elements is rewarded with food. First the pigeons have to learn to discriminate the combinations A/B and B/C with one eye, and C/D and D/E with the other one. Afterwards, they can use both eyes to decide between, for example, the colours B/D. However, only birds with embryonic light experience are able to solve this problem.
Eating Berries Benefits the Brain
Science Daily (Mar. 7, 2012) — Strong scientific evidence exists that eating blueberries, blackberries, strawberries and other berry fruits has beneficial effects on the brain and may help prevent age-related memory loss and other changes, scientists report. Their new article on the value of eating berry fruits appears in ACS' Journal of Agricultural and Food Chemistry.
Barbara Shukitt-Hale, Ph.D., and Marshall G. Miller point out that longer lifespans are raising concerns about the human toll and health care costs of treating Alzheimer's disease and other forms of mental decline. They explain that recent research increasingly shows that eating berry fruits can benefit the aging brain. To analyze the strength of the evidence about berry fruits, they extensively reviewed cellular, animal and human studies on the topic.
Their review concluded that berry fruits help the brain stay healthy in several ways. Berry fruits contain high levels of antioxidants, compounds that protect cells from damage by harmful free radicals. The two also report that berry fruits change the way neurons in the brain communicate. These changes in signaling can prevent inflammation in the brain that contribute to neuronal damage and improve both motor control and cognition. They suggest that further research will show whether these benefits are a result of individual compounds shared between berry fruits or whether the unique combinations of chemicals in each berry fruit simply have similar effects.
Barbara Shukitt-Hale, Ph.D., and Marshall G. Miller point out that longer lifespans are raising concerns about the human toll and health care costs of treating Alzheimer's disease and other forms of mental decline. They explain that recent research increasingly shows that eating berry fruits can benefit the aging brain. To analyze the strength of the evidence about berry fruits, they extensively reviewed cellular, animal and human studies on the topic.
Their review concluded that berry fruits help the brain stay healthy in several ways. Berry fruits contain high levels of antioxidants, compounds that protect cells from damage by harmful free radicals. The two also report that berry fruits change the way neurons in the brain communicate. These changes in signaling can prevent inflammation in the brain that contribute to neuronal damage and improve both motor control and cognition. They suggest that further research will show whether these benefits are a result of individual compounds shared between berry fruits or whether the unique combinations of chemicals in each berry fruit simply have similar effects.
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