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Rediscovering the Aging BrainBCM's 'brain trust' tracks what makes the mind tick into old ageby Ross Tomlin  Michael Friedlander, Ph.D. If you thought old age was synonymous with declining memory and learning skills, think again. Increasingly, neuroscience, the study of the brain and nervous system, is finding that the aging brain is not necessarily doomed. In particular, scientists at Baylor College of Medicine are forging new inroads into understanding the brain that will be increasingly important as the population gets older. "A whole host of research over the last decade has indicated that while there are a number of processes that younger brains do better—picking up a new language, for instance—the older brain is quite capable of taking on new challenges, learning new things and showing a tremendous amount of plasticity," said Michael Friedlander, Ph.D., Chair of Neuroscience and Director of Neuroscience Initiatives at BCM. Plasticity refers to the brain's ability to adapt and change its functional properties in response to experiences, thoughts and emotions. Current research in neuroscience aims to capitalize on the brain's innate ability to adapt in order to fix itself by accessing the intrinsic plasticity mechanisms, a remarkable quality evident in many stroke patients who can either partially or totally recover lost speech and motor skills with intensive therapy over time. Such functional recovery not only manifests at the level of improved performance, but also can be visualized with functional brain scans. Friedlander said the brain's self-repair mechanisms hold the key to better understanding the relationships between plasticity, memory formation and learning ability, as well as improving brain function well into the golden years. Future avenues of research will look to combine the selective activation of these intrinsic processes with drugs and therapies to enhance repair and regeneration. Scores of ongoing research projects in BCM's Neuroscience Department are eavesdropping on the brain's complex operations to figure out what happens as nerve cells age. Understanding the healthy brain can provide clues about fixing a range of problems spanning mild forgetfulness to devastating dementias such as Alzheimer's disease. "If you intend to figure out what's really wrong with the brain that can't learn right or remember right, you better darn well understand what learning and memory are first," said Friedlander. "If you don't know what the process is in normalcy, you can't understand what's wrong when it's broken." Studies of learning and memory show that the biological processes that mediate both are many of the same processes involved in the brain's plasticity. Injuries that affect motor function illustrate how these processes overlap. "You see an 'invasion' of the (damaged) territory by innervation (an increase in nerve supply) from other undamaged parts of the body," said Friedlander. "For example, an area of the brain that normally receives input from the forearm from which nerves are cut or impaired will initially go silent immediately after the injury. However, that area of the brain can become reinvigorated by unmasking its ability to process information from nerves from the fingers and surrounding tissue, becoming functional again." Understanding such mechanisms that occur in response to nervous system injury can also be applied to the processes of learning and memory. For example, learning in the brain initially engages the cellular machinery that alters the efficiency of communication between nerve cells. In order for these processes to lead to formation of memories, such learning requires the activation of genes, including those that control the brain's growth processes, within these cells. Some of the same processes that affect functional reorganization after injury also play a role in learning and memory. Thus, the brain's ongoing capacity for learning throughout life and its ability to reorganize after certain types of injury suggests to researchers that damage done to the nervous system may be minimized, if not reversed, with appropriate activation of the brain's intrinsic repair and plasticity mechanisms. Several answers to questions about learning, memory and plasticity could come from analyzing behavioral addictions. An addiction of most any kind is essentially a learned behavior that results when reward signals in the brain are stimulated by a particular activity (such as sex, alcohol, drugs, eating or gambling). That activity can become associated with other elements in the environment, changing the brain's circuitry so that the addicted person links the cues in the environment to the addiction. For example, a smoker may find drinking in a smoky bar a cue to pick up a cigarette.  John Dani, Ph.D. Understanding the mechanisms that govern addiction – the research focus of John Dani, Ph.D., Professor of Neuroscience and of Psychiatry and Behavioral Sciences – could shed light on the role of reward in all learning processes. Dani studies how the brain's reward systems change during aging and how this affects learning. BCM neuroscientists are also studying the role of stress in learning and memory. While moderate amounts of stress facilitate learning (such as studying for a test or preparing a speech) and excessive stress can obstruct it, the mechanisms behind the brain's ability to learn and focus attention under such conditions and how those processes age are not well understood—yet. Even though many brain functions, such as reflexes, slow with age, senescence doesn't mean a decline in mental faculties across the board. While the jury is still out on the purported benefits of so-called "brain food" (such as fish oil tablets) and "brain games" (such as crossword puzzles and specially marketed computer software), old-fashioned aerobic activity has been shown to stimulate formation of new nerve cells in the brain in the area known to be involved in memory creation. Exactly how these new neurons get integrated into the networks that govern communication between nerve cells and whether the addition of more neurons is helpful are also topics of current research. Harnessing the brain's regenerative ability is particularly promising with regard to salvaging memory. As the devastating effects of Alzheimer's disease attest, the essence of the human psyche represents the sum of that person's memories, which thus become increasingly valuable to the life experience as one ages. One researcher's work on memory formation in fruit flies, for instance, is giving other researchers at BCM ideas about strategic interventions when the brain's learning and memory systems fail. Learning to walk early in life requires synchronicity among memory, learning and plasticity until it becomes "automatic." In the same way, synchronization among these three processes is critical to proper mental maintenance on the opposite end of the life cycle. With the input of creative scientists such as those at BCM, there is hope that the population can remain mentally productive and agile as it ages. |
FeaturesNewsBCM Cancer Center One of Select Few SpotlightBert O'Malley: A Pioneer in Molecular Endocrinology Making Sense of the Sense of Touch Severe Skin Conditions Take a Back Seat at Camp Dermadillo Health Economist Must Put Price Tag on the Priceless Doctor Creates Cartoon that "Bugs" Kids About the Risks of Tobacco BriefsLiving Longer is Smelly Business Clinical Trials for Cancer Southward Bound Green Tea Component Blocks HIV Cell Entry Genetics Technique Takes Bite out of Research Barriers Sports Legends Lend Helping Hands, Arms to College Development & Alumni NewsMitchell Gift Furthers Brain Research Lambert Receives Lifetime Achievement Award Kleberg Foundation Gift Establishes RNAi Screening Core Facility Alumnus Named White House Fellow
Tailoring Technology to Benefit You, the Patient In both human and animal studies, collaborative research programs at the basic, translational and clinical levels at BCM are centering on the brain's normal processes as a stepping stone to demystifying neurological disorders. For example: Ron Davis, Ph.D., Professor of Molecular and Cellular Biology, Neuroscience and Psychiatry and Behavioral Sciences, has conducted basic science research in fruit flies, charting the migration of memory from one part of the brain to another with the passage of time. Kimberly Tolias, Ph.D., Assistant Professor of Neuroscience, is investigating how experience from learning and memory formation and the developmental process affect neuronal (brain cellular) structure and vice versa. Andreas Tolias, Ph.D., Assistant Professor of Neuroscience, has pioneered a novel technique that makes it possible to record precisely the electrical activity of individual brain cells over days, weeks and even months, thus monitoring their signaling responses to learned stimuli, thoughts and planning of actions in real time. Previously, such observations could be done for only a few minutes or hours. Read Montague, Ph.D., Professor of Neuroscience and Psychiatry and Behavioral Sciences, as well as Director of BCM's Human Neuroimaging Lab, has invented a technology that enables simultaneous functional imaging of microscopic blood flow changes (reflecting the activity of nearby neurons as they process information) in several people while they engage in a social interactions between each other. These tasks demand the use of memory, social cues and models of how one relates to others—all processes that can become compromised with aging. Hui Zheng, Ph.D., Professor of Cell and Molecular Biology and of Neuroscience and member of the Huffington Center on Aging, is studying the molecular signals that allow communication along the inside of the nerve cell's structural scaffold in Alzheimer's disease, developing new potential therapeutic targets. |
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Volume 3, Issue 2, Summer 2007 |
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| Last modified: September 21, 2007 |