To sleep, perchance to learn?

Sleep deprivation is ubiquitous in today’s society, and we have all felt the effects of sleep loss on our ability to function optimally, physically and especially mentally. In particular, it has become clear that the brain requires sleep to efficiently establish many forms of long-term memory. However, it is still unknown what sleep deprivation actually does to the brain to impair its function. In a recently published review in the journal Cellular Signalling, authors Christopher G. Vecsey from Brandeis University and Robbert Havekes and Ted Abel from the University of Pennsylvania have tried to capture the current state of our knowledge about the molecular and cellular effects of sleep deprivation that could explain why sleep loss is so detrimental for memory formation. The review focuses primarily on memories for events and places, which are thought to be formed and stored in the area of the brain called the hippocampus.

A key approach to learn about the nitty-gritty effects of sleep deprivation has been research in rodents. Therefore, the authors begin by summarizing how sleep deprivation studies are carried out in rodents, and how sleep deprivation affects memory and several signaling pathways in the brain. Notably, they review the effects of sleep loss on neurotransmitter systems such as acetylcholine, glutamate, and GABA, all of which could potentially modulate learning and memory. The authors also discuss some of the newest and most exciting studies on the topic of sleep loss, including a handful of experiments in which researchers have been able to reverse the effects of sleep deprivation through pharmacological treatments. For example, the authors describe one of their own studies in which sleep deprivation in mice caused memory deficits and reduced signaling through the cAMP pathway, which is known to be crucial for long-term memory. This molecular effect was likely caused by accelerated breakdown of cAMP by phosphodiesterase 4 (PDE4). When mice were treated with a PDE4 inhibitor during the period of sleep deprivation, memory formation remained unaffected. Rescue of memory defects were also obtained in separate studies in which rodents were treated either with nicotine, caffeine, or CPT, an antagonist of the adenosine A1 receptor. Two related studies also found that the effects of sleep deprivation on memory could be ameliorated by prevention of transmitter release from cells in the brain called glia. This was the first indication that brain cells other than neurons are impacted by sleep deprivation and that they contribute to the effects of sleep loss on the ability to remember new information.

As the authors mention, goals for studies in the immediate future will be to identify additional ways that sleep deprivation affects the brain, determine why sleep deprivation targets these molecules, and discover how these targets interact with each other to impair the normal function of the brain. Finally, hopefully our growing knowledge can be used to develop treatments for the cognitive deficits produced by sleep loss in people, especially those who have impaired sleep due to a medical condition, such as insomnia, chronic pain, sleep apnea, or one of the many neurodegenerative or psychiatric disorders associated with disturbed sleep patterns.

Christopher G. Vecsey is a postdoctoral fellow in the Griffith Lab at Brandeis, where he continues to work on interactions between sleep and learning. Chris is supported by a postdoctoral fellowship from the National Institute of Mental Health.

What we can learn about aging from worms

Coleen Murphy from the Dept of Molecular Biology at Princeton will tell us about “Slowing the Ticking Clock: What we can learn about aging and memory from C. elegans at the first Ruth Ann and Nathan Perlmutter Science Forum on Wednesday, March 9 at 4:00 pm in Gerstenzang 121. The focus of her research is on understanding the genes that regulate longevity, using C. elegans as a model system. Coleen performed her Ph.D. thesis research with Jim Spudich at Stanford where she studied myosin motors and then went on to  a post doctoral fellowship with Cynthia Kenyon at UCSF where she began studying aging. Since starting her own lab at Princeton, Coleen has been the recipient of numerous prestigious awards including a Pew Scholar Award, a Keck Distinguished Young Scholar Award, and an NIH Director’s Innovator Award. Her lab’s most recent work showed that TGF-β and insulin signaling regulates reproductive aging. In addition, her lab has also recently been looking into the connection between longevity mutants and memory in C. elegans

About the Forum: Ruth Ann Perlmutter has been a longtime friend of Brandeis University. In 1969, Nathan Perlmutter became vice president of development at Brandeis during the presidency of Morris Abrams. Perlmutter left Brandeis to become the National Director of the Anti Defamation League. Together the Perlmutters were leaders in the interfaith movement and civil rights debates for which activities Nathan received the Presidential Medal of Freedom shortly before his death in 1987. Mrs. Perlmutter earned her B.A. from the University of Denver and her masters degree in sociology from Wayne State University in Detroit. She is a sculptor and painter in her own right and currently lives in Prescott, Arizona.

Wingfield Receives 2010 Baltes Distinguished Research Achievement Award

Update; BrandeisNOW has a in-depth profile on Prof. Wingfield.

Professor Arthur Wingfield is the 2010 recipient of the Baltes Distinguished Research Achievement Award. The $5000 award, given annually by the Margaret M. and Paul B. Baltes Foundation and Division 20 (Adult Development and Aging) of the American Psychological Association (APA), recognizes outstanding contributions to our understanding of adult development and aging. As part of the award, Wingfield will deliver a keynote address at the next annual meeting of the APA.

The number of adults age 65 or older in the US is expected to grow from 35 million in the year 2000, to 70.3 million in 2030.  Among this group, hearing loss is the third most prevalent chronic medical condition, exceeded only by arthritis and hypertension.  The hearing loss associated with adult aging, or presbycusis (literally, “old hearing”) presents a more complex picture than many realize. Whether the loss is mild or more severe, the source is a thinning of hair cells located in the cochlea, a spiral-shaped structure about only the size of the nail on your little finger. There are also “higher level” effects that include the pathways from the cochea to the brain, and age-related changes in the auditory receiving areas of the brain itself. These biological changes result in the older listener expending attentional effort that is not only tiring, but can draw on resources that would ordinarily be available for encoding what has been heard in memory.

This recent award recognizes Wingfield and his Brandeis colleagues’ contributions to understanding this complex interaction between sensory and cognitive changes in adult aging.  Arthur Wingfield is the Nancy Lurie Marks Professor of Neuroscience and director of the Volen National Center for Complex Systems at Brandeis.  His work has also been recognized by the American Speech, Language and Hearing Association, and two successive MERIT Awards from the NIH’s National Institute on Aging.

Brandeis hosts International Workshop on Learning and Memory

25 internationally recognized scientists gathered at Brandeis University from October 3-5, 2010, to discuss recent progress in understanding the neural mechanisms that promote learning. The workshop was sponsored by the Science of Learning Division of the National Science Foundation in a grant to Brandeis University Professor John Lisman, the Zalman Abraham Kekst Chair in Neuroscience. Lisman and Dr. Emrah Duzel, a neurologist from University College London, were the co-organizers of the workshop. Among the leading scientists attending were Mortimer Mishkin, Chief of the Cognitive Section on Neuroscience at NIMH, and the Nobel Prize recipient, Susumu Tonegawa.

The question of how the brain changes during learning has long fascinated scientists. In 1949 the Canadian psychologist, Donald Hebb, proposed that learning new associations involves changes in the strength of synapses. Subsequent work in many laboratories established that synapses do change as we learn and that the process rather closely follows the specific rule that Hebb had postulated.  Recent work, however, has revealed a limitation of Hebb’s rule; the forming of associations depends on the novelty of incoming information and on the motivation to learn, factors that Hebb’s rule cannot account for. The purpose of the workshop was to see how Hebb’s rule could be revised to take into consideration the new findings.

Neuroscience Movie Night

News for Neuroscience and Biology undergrads from the Neuroscience UDRs:

The first Neuroscience Movie Night will be Thursday, Feb 12th from 6-9pm in Volen 105!  We will be showing the movie Memento, a psychological thriller about a man with short-term memory loss.  The film will be followed by a discussion led by Professor John Lisman, Neuroscience Program Chair on recent findings on short-term memory. There will be FREE PIZZA as well!

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