Using synthetic evolution to study the brain: Researchers model key part of neurons

October 2, 2009

The human brain has evolved over millions of years to become a vast network of billions of neurons and synaptic connections. Understanding it is one of humankind's greatest pursuits.

But to understand how the brain processes information, researchers must first understand the very basics of — even down to how proteins inside the neurons act to change the neuron's voltage.

To do so requires a balance of experimentation and computer modeling — a partnership across disciplines traversed by Bill Kath, professor of engineering sciences and applied mathematics in the McCormick School of Engineering and Applied Science, and Nelson Spruston, professor of neurobiology and physiology in the Weinberg College of Arts and Sciences.

The two have worked together for more than a decade, with Spruston designing experiments and Kath developing computer models that explain the results that Spruston found. (It also works the other way: Kath's models have provided Spruston with ideas to test experimentally.)

Spruston has been studying of neurons that change their shape when activated, allowing sodium to enter from outside the neuron. This changes the voltage of the neuron, causing the neuron to fire and send off a chain of within the brain. The difficulty in modeling such behavior lies in the time scale over which this happens — anywhere from fractions of a millisecond out to several seconds.

So the two, along with graduate student Vilas Menon, took a cue from nature and used the process of to study one of evolution's greatest achievements.

Evolutionary algorithms work like this: rather than making one model, researchers make 100 models with many different parameters. They then run those models (using high-speed computers) and compare the results to the experimental data to see how well they match. Researchers then keep the best traits of different models and mix and match (breeding) to make 100 more models. Thousands of generations later they get a model that matches the characteristics of the real thing. Researchers have used this technique in modeling before, but Kath and colleagues introduced a new twist: they allowed the structure of the model (not just its parameters) to be "mutated" during the "breeding".

"In the end, the computer found a quite simple state-dependent model for the sodium channels that provides a very accurate behavior on short time scales and out to several seconds, as well," Kath says. Their results were recently published in the Proceedings of the National Academy of Sciences.

Modeling of even this small a process is important, Spruston says, because it helps scientists understand the important details about how the brain works.

"We want to make sure we truly understand how these channels work by building a model that can recapitulate all the features we've observed," he says. "Making computer models is a way of identifying both what you understand and also where the gaps in your knowledge need to be filled. The cool thing is you're taking a page from a part of biology — evolution — and applying it to another part of biology — neurobiology — and using the computer in the middle."

The neurons the group studied are in the hippocampal region of the , which researchers have identified as being important for memory.

"If you want to understand how this neural circuit is processing information and memory, you have to understand how these neurons behave in different situations," Kath says. "If you leave out key details, you might miss something important."

Source: Northwestern University (news : web)


Rank 5 /5 (1 vote)
Related Stories
Relevant PhysicsForums posts
  • Factors affecting beet root cell membrane
    created4 hours ago
  • Stem cell question.
    createdFeb 10, 2012
  • Protease cleavage
    createdFeb 10, 2012
  • Pertubance in a model
    createdFeb 10, 2012
  • Cancer drugs and Alzheimer's, Oh my!
    createdFeb 09, 2012
  • Squishing cells
    createdFeb 09, 2012
  • More from Physics Forums - Biology

More news stories

A mitosis mystery solved: How chromosomes align perfectly in a dividing cell

Although the process of mitotic cell division has been studied intensely for more than 50 years, Whitehead Institute researchers have only now solved the mystery of how cells correctly align their chromosomes during symmetric ...

Biology / Cell & Microbiology

created 29 minutes ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

The proteins ensuring genome protection

Researchers from the University of Geneva (UNIGE), Switzerland, have discovered the crucial role of two proteins in developing a cell 'anti-enzyme shield'. This protection system, which operates at the level of molecular ...

Biology / Cell & Microbiology

created 29 minutes ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

Researchers find extensive RNA editing in human transcriptome

In a new study published online in Nature Biotechnology, researchers from BGI, the world's largest genomics organization, reported the evidence of extensive RNA editing in a human cell line by analysis of RNA-seq data, demons ...

Biology / Biotechnology

created 29 minutes ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

Entire genome of extinct human decoded from fossil

(PhysOrg.com) -- In 2010, Svante Pääbo and his colleagues presented a draft version of the genome from a small fragment of a human finger bone discovered in Denisova Cave in southern Siberia. The ...

Biology / Biotechnology

created Feb 07, 2012 | popularity 4.7 / 5 (58) | comments 48 | with audio podcast

Why are there so few fish in the Earth's oceans?

(PhysOrg.com) -- A Stony Brook University researcher has found that, contrary to popular belief, there are not plenty of fish in the sea.

Biology / Plants & Animals

created Feb 08, 2012 | popularity 4.3 / 5 (17) | comments 27 | with audio podcast


Scientists discover molecular secrets of 2,000-year-old Chinese herbal remedy

For roughly two thousand years, Chinese herbalists have treated Malaria using a root extract, commonly known as Chang Shan, from a type of hydrangea that grows in Tibet and Nepal. More recent studies suggest that halofuginone, ...

New method to examine batteries -- MRI from the inside

There is an ever-increasing need for advanced batteries for portable electronics, such as phones, cameras, and music players, but also to power electric vehicles and to facilitate the distribution and storage of energy derived ...

Starve a virus, feed a cure? Findings show how some cells protect themselves against HIV

A protein that protects some of our immune cells from the most common and virulent form of HIV works by starving the virus of the molecular building blocks that it needs to replicate, according to research published online ...

Lab study raises questions over nano-particle impact

Tests involving chickens have raised questions about the impact on health from engineered nano-particles, the ultra-fine grains commonly used in drugs and processed foods, scientists said on Sunday.

Iran blocks email, restricts net access: reports

Iran has further restricted access to the Internet and blocked popular email services for the past few days, in a move a top lawmaker said could "cost the regime dearly," media reports said on Sunday.

Salvage workers begin pumping fuel from Italian shipwreck

Salvage workers Sunday began pumping fuel from the shipwrecked Italian cruise liner Costa Concordia, a day ahead of schedule, officials said.