Navigation Links
After 100 years, understanding the electrical role of dendritic spines

It's the least understood organ in the human body: the brain, a massive network of electrically excitable neurons, all communicating with one another via receptors on their tree-like dendrites. Somehow these cells work together to enable great feats of human learning and memory. But how?

Researchers know dendritic spines play a vital role. These tiny membranous structures protrude from dendrites' branches; spread across the entire dendritic tree, the spines on one neuron collect signals from an average of 1,000 others. But more than a century after they were discovered, their function still remains only partially understood.

A Northwestern University researcher, working in collaboration with scientists at the Howard Hughes Medical Institute (HHMI) Janelia Farm Research Campus, has recently added an important piece of the puzzle of how neurons "talk" to one another. The researchers have demonstrated that spines serve as electrical compartments in the neuron, isolating and amplifying electrical signals received at the synapses, the sites at which neurons connect to one another.

The key to this discovery is the result of innovative experiments at the Janelia Farm Research Campus and computer simulations performed at Northwestern University that can measure electrical responses on spines throughout the dendrites.

A paper about the findings, "Synaptic Amplification by Dendritic Spines Enhances Input Cooperatively," was published November 22 in the journal Nature.

"This research conclusively shows that dendritic spines respond to and process synaptic inputs not just chemically, but also electrically," said William Kath, professor of engineering sciences and applied mathematics at Northwestern's McCormick School of Engineering, professor of neurobiology at the Weinberg College of Arts and Sciences, and one of the paper's authors.

Dendritic spines come in a variety of shapes, but typically consist of a bulbous spine head at the end of a thin tube, or neck. Each spine head contains one or more synapses and is located in very close proximity to an axon coming from another neuron.

Scientists have gained insight into the chemical properties of dendritic spines: receptors on their surface are known to respond to a number of neurotransmitters, such as glutamate and glycine, released by other neurons. But because of the spines' incredibly small size roughly 1/100 the diameter of a human hair their electrical properties have been harder to study

In this study, researchers at the HHMI Janelia Farm Research Campus used three experimental techniques to assess the electrical properties of dendritic spines in rats' hippocampi, a part of the brain that plays an important role in memory and spatial navigation. First, the researchers used two miniature electrodes to administer current and measure its voltage response at different sites throughout the dendrites.

They also used a technique called "glutamate uncaging," a process that involves releasing glutamate, an excitatory neurotransmitter, to evoke electrical responses from specific synapses, as if the synapse had just received a signal from a neighboring neuron. A third process utilized a calcium-sensitive dye calcium is a chemical indicator of a synaptic event injected into the neuron to provide an optical representation of voltage changes within the spine.

At Northwestern, researchers used computational models of real neurons reconstructed from the same type of rat neurons to build a 3D representation of the neuron with accurate information about each dendrites' placement, diameter, and electrical properties. The computer simulations, in concert with the experiments, indicated that spines' electrical resistance is consistent throughout the dendrites, regardless of where on the dendritic tree they are located.

While much research is still needed to gain a full understanding of the brain, knowledge about spines' electrical processing could lead to advances in the treatment of diseases like Alzheimer's and Huntington's diseases.

"The brain is much more complicated than any computer we've ever built, and understanding how it works could lead to advances not just in medicine, but in areas we haven't considered yet," Kath said. "We could learn how to process information in ways we can only guess at now."

Contact: Megan Fellman
Northwestern University

Related medicine news :

1. Mayo Clinic: Less invasive surgery detects residual breast cancer in lymph nodes after chemotherapy
2. Rejected hearts now viable for transplantation after stress echo
3. Smoking may worsen hangover after heavy drinking
4. The US Drug Watchdog Now Urges Women Who Suffered A Heart Attack Or Stroke After Using Yaz Yasmin Birth Control Pills To Contact The Johnson Law Group Immediately
5. U.S. Kids Might Not Be Over-Medicated After All
6. Experts urge rapid evaluation for swallowing and voice problems after brain surgery
7. Certain Arthritis Patients Fare Worse After Joint Replacement: Study
8. Complications challenge rheumatoid arthritis patients after joint replacement surgery
9. U.S. Kids Getting Enough Sleep After All: Survey
10. Imaging shows some brains compensate after traumatic injury
11. Researchers find evidence that brain compensates after traumatic injury
Post Your Comments:
Related Image:
After 100 years, understanding the electrical role of dendritic spines
(Date:6/26/2016)... ... ... On June 10-11, 2016, A Forever Recovery, a holistic treatment center for ... Table in Battle Creek, MI, where the rehabilitation facility is located. This annual celebration ... world’s leading providers of cereal and other breakfast foods. Its residents often refer to ...
(Date:6/25/2016)... ... June 25, 2016 , ... Experts from the American Institutes ... Research Meeting June 26-28, 2016, at the Hynes Convention Center in Boston. , ... advance care planning, healthcare costs and patient and family engagement. , AIR researchers ...
(Date:6/25/2016)... ... June 25, 2016 , ... As a lifelong Southern Californian, Dr. Omkar ... M.D from the David Geffen School of Medicine at UCLA. He trained in Internal ... complete his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai program where he had ...
(Date:6/24/2016)... Marne, Michigan (PRWEB) , ... June 24, 2016 , ... ... To deal with these feelings, many turn to unhealthy avenues, such as drug or ... Center of Marne, Michigan, has released tools for healthy coping following a traumatic event. ...
(Date:6/24/2016)... , ... June 24, 2016 , ... ... offering micro-osteoperforation for accelerated orthodontic treatment. Dr. Cheng has extensive experience with all ... brackets , AcceleDent, and accelerated osteogenic orthodontics. , Micro-osteoperforation is a revolutionary ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... Research and Markets has announced the addition of the ... report to their offering. ... failure, it replaces the function of kidneys by removing the ... the treatment helps to keep the patient body,s electrolytes such ... Increasing number of ESRD patients & substantial healthcare expenditure on ...
(Date:6/23/2016)... 23, 2016 Research and Markets has ... Market Analysis 2016 - Forecast to 2022" report to ... report contains up to date financial data derived from varied ... major trends with potential impact on the market during the ... segmentation which comprises of sub markets, regional and country level ...
(Date:6/23/2016)... PARK RIDGE, Ill. and INDIANAPOLIS ... caliber of students receiving a Lilly Diabetes Tomorrow,s Leaders ... hands. The 2016 scholarship winners, announced today online at ... refused to let type 1 diabetes stand in the ... Lilly Diabetes has supported the Foundation,s scholarship program since ...
Breaking Medicine Technology: