Neurosciences

Mayo Clinic researchers have created a map of the brain and found that activity lingers longer, in certain areas, in those with Alzheimer’s than it ...

ROCHESTER, Minn. — July 12, 2012.  Problems walking including slow gait and a short stride are associated with an increased risk of cognitive decline, Mayo Clinic researchers have discovered. Their findings are being presented at the Alzheimer's Association International Conference July 14–19 in Vancouver, British Columbia. Mayo Clinic researchers are presenting on several topics, including the following: MULTIMEDIA ALERT: For multimedia resources including interviews with study authors visit Mayo Clinic News Network. Gait disturbances linked with decline in cognitive function Researchers measured the stride length, cadence and velocity of more than 1,341 participants through a computerized gait instrument at two or more visits roughly 15 months apart. Researchers found that study participants with lower cadence, velocity and length of stride experienced significantly larger declines in global cognition, memory and executive function. "These results support a possible role of gait changes as an early predictor of cognitive impairment," said study author Rodolfo Savica, M.D., a Mayo Clinic neurologist. Researchers refine guidelines designed to identify Alzheimer's early Mayo Clinic researchers, the National Institute on Aging and the Alzheimer's Association published new guidelines in April for the diagnosis of Alzheimer's disease. They separate the progression of Alzheimer's into three stages: (1) pre-clinical (or pre-symptomatic) Alzheimer's disease, (2) mild cognitive impairment (MCI) due to Alzheimer's disease, and (3) Alzheimer's disease dementia. At this year's conference, Mayo Clinic researchers reported on the validity of Stage 2 MCI. This stage was designed to differentiate patients with early Alzheimer's disease from those with other cognitive issues. Researchers studied 156 people who met the criteria for MCI. Of those, 67 percent had evidence of early Alzheimer's disease. "These results indicate that the new diagnostic criteria for MCI due to Alzheimer's works quite well," said study author Ronald Petersen, M.D., Ph.D, a Mayo Clinic neurologist. "Ultimately, though, the validity of these new criteria will be determined by the long-term outcome of these subjects."

ROCHESTER, Minn. — July 12, 2012.  Activity lingers longer in certain areas of the brain in those with Alzheimer's than it does in healthy people, Mayo Clinic researchers who created a map of the brain found. The results suggest varying brain activity may reduce the risk of Alzheimer's disease. The study, "Non-stationarity in the "Resting Brain's" Modular Architecture," was presented at the Alzheimer's Association International Conference and recently published in the journal PLoS One. Journalists: For multimedia resources, including a graphic of the Road Map, and interview with the study author, visit the Mayo Clinic News Network. Researchers compared brain activity to a complex network, with multiple objects sharing information along pathways. "Our understanding of those objects and pathways is limited," says lead author David T. Jones, M.D. "There are regions in the brain that correspond to those objects, and we are not really clear exactly what those are. We need a good mapping or atlas of those regions that make up the network in the brain, which is part of what we were doing in this study." Researchers examined 892 cognitively normal people taking part in the Mayo Clinic Study of Aging, and set out to create an active map of their brains while the people were "at rest," not engaged in a specific task. To do this, they employed task-free, functional magnetic resonance imaging to construct an atlas of 68 functional regions of the brain, which correspond to the cities on the road map. Researchers filled in the roads between these regions by creating dynamic graphic representations of brain connectivity within a sliding time window. This analysis revealed that there were many roads that could be used to exchange information in the brain, and the brain uses different roads at different times. The question to answer then, said Dr. Jones, is whether or not Alzheimer's patients used this map and these roads in a different way than their healthy peers. "What we found in this study was that Alzheimer's patients tended to spend more time using some roads and less time using other roads, biasing one over the other," he says.

Mayo Clinic researchers have found a novel way to monitor real-time chemical changes in the brains of patients undergoing deep brain stimulation (DBS). This groundbreaking insight ...

ROCHESTER, Minn. — July 11, 2012.  Mayo Clinic researchers have found a novel way to monitor real-time chemical changes in the brains of patients undergoing deep brain stimulation (DBS). The groundbreaking insight will help physicians more effectively use DBS to treat brain disorders such as Parkinson's disease, depression and Tourette syndrome. The findings are published in the journal Mayo Clinic Proceedings. Journalists: For multimedia resources including video of a tremor patient undergoing DBS, visit the Mayo Clinic News Network. Researchers hope to use the discovery to create a DBS system that can instantly respond to chemical changes in the brain. Parkinson's, Tourette syndrome and depression all involve a surplus or deficiency of neurochemicals in the brain. The idea is to monitor those neurochemicals and adjust them to appropriate levels. "We can learn what neurochemicals can be released by DBS, neurochemical stimulation, or other stimulation. We can basically learn how the brain works," says author Su-Youne Chang, Ph.D., of the Mayo Clinic Neurosurgery Department. As researchers better understand how the brain works, they can predict changes, and respond before those changes disrupt brain functioning. Researchers observed the real-time changes of the neurotransmitter adenosine in the brains of tremor patients undergoing deep brain stimulation. Neurotransmitters such as dopamine and serotonin are chemicals that transmit signals from a neuron to a target cell across a synapse. The team used fast scan cyclic voltammetry (FSCV) to quantify concentrations of adenosine released in patients during deep brain stimulation. The data was recorded using Wireless Instantaneous Neurotransmitter Concentration Sensing, a small wireless neurochemical sensor implanted in the patient's brain. The sensor, combined with FSCV, scans for the neurotransmitter and translates that information onto a laptop in the operating room. The sensor has previously identified neurotransmitters serotonin and dopamine in tests in brain tissue. This was the first time researchers used this technique in patients. Tremors are a visual cue that the technique is working; researchers suspect adenosine plays a role in reducing tremors. Researchers also hope to learn more about conditions without such external manifestations. "We can't watch pain as we do tremors," says Kendall Lee, M.D., Ph.D., a Mayo Clinic neurosurgeon. "What is exciting about this electrochemical feedback is that we can monitor the brain without external feedback. So now, we can monitor neurochemicals in the brain and learn about brain processes like pain."

Nat sound video pkg. / interviews / b-roll are available in the downloads above. Sean's Story of Determination and Independence At 23, Sean Bretz was the picture of health.  As a member of the U.S. Coast Guard Sector Jacksonville, you’d expect nothing less. But then last June 5, the machinery technician woke up with what he described as “an excruciating headache.”  Attributing it to a  late night out with friends, Bretz didn’t think much of it and headed to the kitchen, hoping food might help. Instead he collapsed. Friends thought he’d had a seizure. They called 911 and Bretz was transported to Mayo Clinic where doctors determined a giant aneurysm had burst in his brain, causing a massive stroke.  Prognosis was grim. 

SCOTTSDALE, Ariz. — June 28, 2012.  More than 40,000 student athletes in Arizona have taken advantage of computerized baseline concussion evaluations offered by Mayo Clinic, in the program's first year. That amounts to nearly 40 percent of the state's roughly 100,000 high school athletes. Baseline concussion evaluations measure how the brain is working before injury, and are mandatory tests for professional and college athletes. Mayo covers the cost of the cognitive evaluations for all high school and junior high school-aged interscholastic and club athletes in the state. The program was made possible through the support of benefactors and Mayo Clinic. The test takes 8–15 minutes to complete, and athletes or their parents can share the results with health care providers of their choice. After a concussion, the test can be repeated to determine if there has been a change in the cognitive capabilities of the athlete and, once symptoms have resolved, the test can be repeated to determine whether the athlete has returned to pre-injury baseline. The results of this test, combined with a thorough neurological evaluation, ensure that the health care provider can make an informed and objective determination on when and whether the athlete can safely resume normal activities — and in the case of student athletes, when they can return to their sport. "The diagnosis of concussion, assessment of its severity and knowing when an athlete can return to physical activity, competition, work or school is not always clear," says Mayo neurologist David Dodick, M.D., at Mayo Clinic in Arizona and president of the American Headache Society. "Having a baseline concussion assessment for each athlete will assist in a physician's ability to identify and quantify a change in brain function, and determine if and when the athlete has returned to his or her baseline." After a concussion, if an athlete continues to play or returns to play too early, there is a significant risk of experiencing another concussion. Dr. Dodick adds. "Repeat concussions may take longer to resolve and come with a risk of permanent neurological damage or, rarely, death," he says. Children, adolescents and female athletes appear to be at a higher risk for concussions, and may also take longer to recover. While the importance of baseline testing is clear, the results should be used with a comprehensive neurological evaluation. Although the majority of concussions resolve relatively quickly, some athletes may experience symptoms that may persist for months or longer. The medical care and rehabilitation of these athletes is best achieved by a multidisciplinary team of health professionals with expertise in the evaluation and management of concussions. Providing this baseline assessment also highlights the importance of safeguarding the brain health of young athletes.

Researchers at Mayo Clinic in Florida are building a case that says neurodegenerative disorders like Alzheimer’s disease are primarily caused by genes that are too active or ...

JACKSONVILLE, Fla. — June 6, 2012.  Using a new and powerful approach to understand the origins of neurodegenerative disorders such as Alzheimer's disease, researchers at Mayo Clinic in Florida are building the case that these diseases are primarily caused by genes that are too active or not active enough, rather than by harmful gene mutations. VIDEO ALERT: Video resources of Nilufer Ertekin-Taner, M.D., Ph.D., discussing the study are available here. In the June 7 online issue of PLoS Genetics, they report that several hundred genes within almost 800 brain samples of patients with Alzheimer's disease or other disorders had altered expression levels that did not result from neurodegeneration. Many of those variants were likely the cause. "We now understand that disease likely develops from gene variants that have modest effects on gene expression, and which are also found in healthy people. But some of the variants — elevating expression of some genes, reducing levels of others — combine to produce a perfect storm that leads to dysfunction," says lead investigator Nilufer Ertekin-Taner, M.D., Ph.D., a Mayo Clinic neurologist and neuroscientist. "If we can identify the genes linked to a disease that are too active or too dormant, we might be able to define new drug targets and therapies," she says. "That could be the case for both neurodegenerative disease as well as disease in general." Dr. Ertekin-Taner says no other lab has performed the extent of brain gene expression study conducted at Mayo Clinic's Florida campus. "The novelty, and the usefulness, of our study is the sheer number of brain samples that we looked at and the way in which we analyzed them. These results demonstrate the significant contribution of genetic factors that alter brain gene expression and increase risk of disease," she says. This form of data analysis measures gene expression levels by quantifying the amount of RNA produced in tissue and scans the genome of patients to identify genetic variants that associate with these levels. Mayo researchers measured the level of 24,526 transcripts (messenger RNA) for 18,401 genes using cerebellar autopsy tissue from 197 Alzheimer's disease patients and from 177 patients with other forms of neurodegeneration. The researchers then validated the results by examining the temporal cortex from 202 Alzheimer's disease patients and from 197 with other pathologies. The difference between these samples is that while the temporal cortex is affected by Alzheimer's disease, the cerebellum is relatively spared. From these analyses, the researchers identified more than 2,000 markers of altered expression in both groups of patients that were common between the cerebellum and temporal cortex. Some of these markers also influenced risk of human diseases, suggesting their contribution to development of neurodegenerative and other diseases regardless of their location in the brain. They identified novel expression "hits" for genetic risk markers of diseases that included progressive supranuclear palsy, Parkinson's disease, and Paget's disease, and confirmed other known associations for lupus, ulcerative colitis, and type 1 diabetes. "Altered expression of brain genes can be linked to a number of diseases that affect the entire body," Dr. Ertekin-Taner says.

ROCHESTER, Minn. — May 23, 2012.  At Mayo Clinic, the name Clifford Jack Jr., M.D., means cutting-edge imaging and Alzheimer's research. This month, he was ...

Journalists: Mayo Clinic experts are available for Stroke Awareness Month. Mayo Clinic neurologist Kevin Barrett, M.D., stroke expert on Florida campus. Contact Media Relations: 904-953-2299 ...

Your computer has a lot of 'memory' and using the computer, plus exercising, could help you keep your memory. In the May issue of Mayo Clinic Proceedings researchers say ...