Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New discoveries about neuron plasticity linked to learning and memory

02.11.2005


Neurons experience large-scale changes across their dendrites during learning, say neuroscientists at The University of Texas at Austin in a new study that highlights the important role that these cell regions may play in the processes of learning and memory.


The research, published online Oct. 23 and in the November issue of the journal Nature Neuroscience, shows that ion channels distributed in the dendritic membrane change during a simulated learning task and that this requires the rapid production of new proteins.

"Our new work strongly supports the idea that learning involves changes in dendrites," says Dr. Daniel Johnston, director of the Center for Learning and Memory and professor in the Institute for Neuroscience.

The finding could also lead to advances in understanding conditions like epilepsy and age-related memory loss and could point to potential treatment opportunities for such conditions in the future.



Dendrites--the thin branch-like extensions of a neuron cell--receive many inputs from other neurons that transmit information through contact points called synapses. Much attention has been focused on the role that changes at synapses play in learning. They change in ways that make it easier for connected neurons to pass information.

Johnston and his colleagues show that learning and memory are likely to not only involve changes at synapses, but also in dendrites. They found that h-channels, which are distributed throughout the dendrite membrane and allow the passage of potassium and sodium ions into and out of the neuron, are altered during learning.

"The h-channels undergo plasticity, not near the synapse but probably throughout the dendritic tree," says Johnston.

To record the changes during learning, cells from the rat hippocampus (an important area of the brain for short-term memory) were electrically stimulated using a high frequency pattern called theta-bursts. Theta-bursts mimic the electrical stimulus that shoots through neurons when animals perform a learning task. The researchers found that when stimulated with theta-bursts, hippocampus neurons showed h-channel plasticity and a rapid increase in the synthesis of h-channel proteins.

The proteins were produced in the rat hippocampal neurons within 10 minutes, which is pretty rapid for cells, says Johnston.

"This really pushes the envelope with respect to how fast a neuron can produce new proteins important for learning," he says.

Learning and memory researchers know that protein synthesis in neurons is related to long-term memory, because protein synthesis inhibitors block long-term memory in animals.

Johnston says it’s possible that the new proteins are being used by the neuron to build more h-channels in the dendrite membrane. He has a working hypothesis that h-channels may help buffer receiving neurons from being barraged and over-stimulated by inputs coming from information transmitting neurons.

"The h-channel plasticity alters the way the entire dendritic tree responds to the synaptic inputs," he says.

H-channel plasticity may normalize the firing rate of the cell.

"If cells aren’t kept in a normal operating regime, learning would not be as effective," Johnston says. "H-channel plasticity might keep the cell within an operating window in which it can continue to learn."

Dan Johnston | EurekAlert!
Further information:
http://www.clm.utexas.edu

More articles from Life Sciences:

nachricht Clock stars: Astrocytes keep time for brain, behavior
27.03.2017 | Washington University in St. Louis

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Electrical 'switch' in brain's capillary network monitors activity and controls blood flow

27.03.2017 | Health and Medicine

Clock stars: Astrocytes keep time for brain, behavior

27.03.2017 | Life Sciences

Sun's impact on climate change quantified for first time

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>