Neuroscientists have long wondered how individual connections between brain cells remain diverse and "fit" enough for storing new memories. Reported in the prestigious science journal Neuron, a new study led by Dr. Inna Slutsky of the Sackler School of Medicine at Tel Aviv University describes what makes some memories stick.
The key is GABA (ã-Aminobutyric acid), a natural molecule that occurs in the brain, which could be the main factor in regulating how many new memories we can generate, the new study has found. The understanding of these mechanisms might lead to the development of new memory enhancers and new treatments for neurodegenerative diseases such as Alzheimer's.
Memories, Dr. Slutsky says, are stored in synaptic connections between neurons in our brain. In the past, other teams, including her own, have demonstrated that the strength of individual synapses is highly variable, even at the single neuron level. This variability ultimately determines if and how new memories are stored, and the key to this variability is GABA, a naturally-occurring chemical found in the brain.
In the hippocampus, one of the main areas of the brain involved in learning and memory, the strength of neuronal connections is known to be highly variable. Some neurons are tightly connected to others, while some appear to be "lone rangers."
The new paper, which examines individual synapses in the hippocampus, demonstrates that this process is regulated by GABA, the main inhibitory neurotransmitter in our brain. "We determined that variations in the local level of GABA in the vicinity of individual synapses are responsible for the differences or 'heterogeneity' of synaptic strength. And this heterogeneity may facilitate the formation of new memories," Dr. Slutsky explains.
Looking at the brain at rest
While looking at the brain in its basal state — when the activity was "at rest" before attempting to memorize a list of items or after a memory had been stored — Dr. Slutsky's team could actually "see" where synapses differ at different dendritic branches in the neuronal network. Those branches of neurons close to a cell body displayed a larger number of weak synapses, while the most distant branches were composed of a smaller number of strong synapses.
"Why the difference?" they asked. GABA was the answer. Higher concentrations of GABA near a synapse induced a stronger activation of its receptors, weakening basal synapse strength. As a result, GABA makes this synapse more liable to the formation of new memories, the researchers propose.
Dr. Slutsky, who previously discovered a basal-state regulator molecule, says that the research may also have implications for treating diseases of the mind. "We found that amyloid-beta, a well-known hallmark of Alzheimer's disease, regulates basal synapse strength in an opposite way to GABA," she notes, suggesting that an increase in the basal activity of synapses may initiate memory decline in Alzheimer's and other neurodegenerative disorders.
Experiments in the study were done using neuronal cultures and brain slices of rats subjected to molecular biology, optical imaging and electrophysiological techniques. The study also constituted a technical achievement, since it used advanced imaging techniques such as fluorescence resonance energy transfer (FRET) spectroscopy that looked at protein-to-protein interactions in the brain at the 10 nanometer scale. In the past, such fine resolution was impossible — brain scientists could only investigate interactions at the level of entire tissues, not between molecules at individual synapses.
George Hunka | EurekAlert!
Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology
Pan-European study on “Smart Engineering”
30.03.2017 | IPH - Institut für Integrierte Produktion Hannover gGmbH
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
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...
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...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
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...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering