A type of protein crucial for the growth of brain cells during development appears to be equally important for the formation of long-term memories, according to researchers at UC Irvine. The findings could lead to a better understanding of, and treatments for, cognitive decline associated with normal aging and diseases such as Alzheimer’s.
The findings appear in the early online edition of the Proceedings of the National Academy of Sciences.
“This study presents strong evidence that a molecular process fundamental during development is retained in the adult and recycled in the service of memory formation,” said Thomas J. Carew, Donald Bren Professor and chair of UCI’s Department of Neurobiology and Behavior. “It is a striking example of how molecular rules employed in building a brain are often reused for different purposes throughout a lifetime.”
The researchers have shown that proteins known as growth factors are as essential for the induction of long-term memory as they are for the development of the central nervous system. These growth factors, such as brain derived neurotrophic factor (BDNF), bind onto the brain cell through a specific type of receptor known as TrkB, much the same way a key fits into a lock. As an experimental strategy to determine the importance of BDNF-like growth factors in forming memories, the researchers used a “molecular trick” to keep the proteins from binding with the appropriate TrkB receptors.
For the experiment, the scientists used wild-caught Aplysia, a marine snail frequently studied in learning and memory because of its large brain cells. The Aplysia received a series of five tail shocks, spaced 15 minutes apart. The shocks cause the animals to exhibit heightened withdrawal reflexes days and weeks after the shocks are over.
When the animals are shocked, a brain chemical known as serotonin is released that promotes the formation of a long-term memory associated with the shocks. However, when Carew and his colleagues blocked the interaction between the BDNF-like growth factors and the TrkB receptors, they found that serotonin alone was not enough to retain the long-term memory of the shock. While short-term memory was retained, 24 hours later the snails – which normally would remember the events of the previous day – exhibited no memory of the shocks. Carew and colleagues went on to show that, when the actions of the growth factors were prevented, long-term enhancement of the connections between the brain cells in the reflex circuit normally induced by the shock treatment was also blocked.
“We would never have expected that the secretion of these growth factors in response to serotonin would be critical for long-term memory formation in this system,” Carew said. “But it is apparent that without them, this process cannot happen.”
According to Carew, these findings could open possible avenues for treatments relating to memory loss. “This gives us some strong clues as to what we should be looking into for therapeutic interventions,” he said. “If we know that growth factors are important for long-term memory, then we can look at possible remedial roles they might play in diseases such as Alzheimer’s and dementia.”
Carew is a pioneer in the field known as the cellular biology of learning, which combines the disciplines of psychology and neurobiology. He held an endowed chair at Yale before coming to UCI in 2000. In 2001 he was elected a fellow of the American Association for the Advancement of Science and was named a fellow of the American Academy of Arts and Sciences in 2004.
Shiv Sharma of the National Brain Research Center in India; and Carolyn Sherff, Shara Stough and Vickie Hsuan of UCI collaborated with Carew on the study, which was funded by the National Institute of Mental Health.
About the University of California, Irvine: The University of California, Irvine is a top-ranked university dedicated to research, scholarship and community service. Founded in 1965, UCI is among the fastest-growing University of California campuses, with more than 24,000 undergraduate and graduate students and about 1,400 faculty members. The second-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3.3 billion. For more UCI news, visit www.today.uci.edu.
Television: UCI has a broadcast studio available for live or taped interviews. For more information, visit www.today.uci.edu/broadcast.
News Radio: UCI maintains on campus an ISDN line for conducting interviews with its faculty and experts. The use of this line is available free-of-charge to radio news programs/stations who wish to interview UCI faculty and experts. Use of the ISDN line is subject to availability and approval by the university.
Farnaz Khadem | EurekAlert!
Molecular evolution: How the building blocks of life may form in space
26.04.2018 | American Institute of Physics
Multifunctional bacterial microswimmer able to deliver cargo and destroy itself
26.04.2018 | Max-Planck-Institut für Intelligente Systeme
Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
26.04.2018 | Power and Electrical Engineering
26.04.2018 | Life Sciences
26.04.2018 | Power and Electrical Engineering