Workings of the Brain: After 100 Years, Understanding the

New Post Public Reply Private Reply Replies (1) Message Board

Dec 6, 2012 at 10:02 AM

Workings of the Brain: After 100 Years, Understanding the Electrical Role of Dendritic Spines
http://www.sciencedaily.com/releases/2012/12/...132429.htm

ScienceDaily (Dec. 5, 2012) — 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.

"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."

Featured stocks: Coffee Shoppe
For conservative debate: "Keeping it Real"
Game Changing stock $SHMP

Newer

Older

Scroll down for more posts ▼

Top 10 Most Recent News Articles

Fermi's Founder Pushes for Board Overhaul: What's Next?

Fermi's Roller Coaster: A Founder’s Stand Seems like Fermi Inc. is on a wild ride through the business landscape, and it's giving shareholders more whiplash than satisfaction these days. Toby Neugebauer, co-founder of Fermi and the loudest voice in the room, is feeling like his company is facing some serious turbulence and seems determined not to sit idly by as it hits...

NYSE Reflects on 9/11: Honoring Lives and Legacy

A Somber Day at NYSE: Reflecting on 9/11 September 11th grips the heart of NYSE every year, but this year's 25th-anniversary powerfully reverberates through its hallowed halls. The hustle of the trading floor halts for a moment at 9:20 AM ET, paying homage to those lost in the harrowing attacks. I've seen the markets flap in the wind of countless crises, but nothing's...

High-Grade Copper Spurs Optimism for PolarX in Alaska

Copper's New Pulse: PolarX Makes Waves in Alaska Ever hear about striking copper so rich it's practically shimmering? Well, PolarX Limited just might have hit that sweet spot up in the rugged expanses of Alaska. Let me tell you, when you're knee-deep in resources, like what they’re discovering at the Caribou Dome Project, it sure feels like you’ve struck modern-day...

2026 Buy-Side Index Reveals State Market Variance

Toss out your one-size-fits-all real estate predictions; the Q2 2026 Buy-Side Index just unveiled some real whoppers about the housing market. What we're seeing isn't your typical year-over-year growth across the board. Nope, we're seeing splits as sharp as a knife between states. Some places are shooting up in price, while others seem to be stuck in mud. Price Surges and...

Melissa Rivers Brings Her Wit Back to Emmys Carpet

They say you can never go home again, but don't tell that to Melissa Rivers. Rolling the dice on nostalgia and kicking off a new chapter, she's waltzing back to the Emmys red carpet for the first time in nearly 20 years. Alright, what's in it for investors? Not much—unless you're looking to invest in nostalgia. But there's something here about legacy, reinvention, and...

Oil Markets Shift Focus: Pipelines Trump Drilling

Decoupling Oil Price and Production Response This oil market isn’t your usual rodeo. With Brent flirting with $100, it’s a seismic shift that’s not yielding new drills but redirecting capital to the existing infrastructure landscape. Ask yourself why we're not seeing the usual cavalry charge of new rigs. It’s simple: Pipeline mileage and producing wells have...

Americas Cardroom's Poker Series Hits $7.2M Haul

Massive Prize Pools Emerge in Just Four Days I found myself eyeballing some jaw-dropping numbers from Americas Cardroom's latest poker series, the Online Super Series XL. It's not every day you see nearly a hundred tournaments rake in over $7.2 million in prize pools in just four days. From September 6th to 9th, a whopping 62,847 entries signed up to make an honest...

Supply Maverick Simplifies Global Shipping Processes

Paving the Way for Seamless International Shipping Supply Maverick's got a new mantra, folks: simplicity. They're slicing through the mess of international shipping and bringing some much-needed clarity for customers in Canada, Australia, and New Zealand. It’s about time someone shook up the logistics playbook. The Nuts and Bolts of the New Shipping System Imagine being...

Lick the Plate Hits 2,000 Shows with Clown Band

They say good things come in bizarre packages, and that's exactly the case as David Boylan's Lick the Plate zany celebration marks 15 years on air with its 2,000th episode. If you think of radio as a predictable endeavor, well, you're not tuned into Lick the Plate. A Milepost Draped in Multicolored Fabrics When you're browsing through colorful avenues of radio fame, it's...

Sustainability Investments: $17 Trillion Wager Faces Divergence

Sustainability Investments: A Tale of Contrasts In the world of sustainability, a staggering $17 trillion has been poured into technologies over the past decade. That’s no chump change. But what do we have to show for it? According to Bain & Company’s latest report, this massive financial injection hasn’t exactly hit a home run. Progress, much like the stock market...