Brain cell networks recreated with new view of activity behind memory formation

A fluorescent image of the neural network model developed at Pitt reveals the interconnection (red) between individual brain cells (blue). Adhesive proteins (green) allow the network to be constructed on silicon discs for experimentation. Credit: U. Pittsburgh

University of Pittsburgh researchers have reproduced the brain's complex electrical impulses onto models made of living brain cells that provide an unprecedented view of the neuron activity behind memory formation.

The team fashioned ring-shaped networks of that were not only capable of transmitting an electrical impulse, but also remained in a state of persistent associated with , said lead researcher Henry Zeringue [zuh-rang], a bioengineering professor in Pitt's Swanson School of Engineering. Magnetic resonance images have suggested that working memories are formed when the , or outer layer of the brain, launches into extended after the initial stimulus, Zeringue explained. But the brain's complex structure and the diminutive scale of mean that observing this activity in real time can be nearly impossible, he added.

The Pitt team, however, was able to generate and prolong this excited state in groups of 40 to 60 brain cells harvested from the of rats—the part of the brain associated with memory formation. In addition, the researchers produced the networks on glass slides that allowed them to observe the cells' interplay. The work was conducted in Zeringue's lab by Pitt bioengineering doctoral student Ashwin Vishwanathan, who most recently reported the work in the Royal Society of Chemistry (UK) journal, Lab on a Chip. Vishwanathan coauthored the paper with Zeringue and Guo-Qiang Bi, a neurobiology professor in Pitt's School of Medicine. The work was conducted through the Center for the Neural Basis of Cognition, which is jointly operated by Pitt and Carnegie Mellon University.

To produce the models, the Pitt team stamped adhesive proteins onto silicon discs. Once the proteins were cultured and dried, cultured hippocampus cells from embryonic rats were fused to the proteins and then given time to grow and connect to form a natural network. The researchers disabled the cells' inhibitory response and then excited the neurons with an electrical pulse.

Zeringue and his colleagues were able to sustain the resulting burst of network activity for up to what in neuronal time is 12 long seconds. Compared to the natural duration of .25 seconds at most, the model's 12 seconds permitted an extensive observation of how the neurons transmitted and held the electrical charge, Zeringue said.

Unraveling the mechanics of this network communication is key to understanding the cellular and molecular basis of memory creation, Zeringue said. The format developed at Pitt makes neural networks more accessible for experimentation. For instance, the team found that when activity in one neuron is suppressed, the others respond with greater excitement.

"We can look at neurons as individuals, but that doesn't reveal a lot," Zeringue said. "Neurons are more connected and interdependent than any other cell in the body. Just because we know how one neuron reacts to something, a whole network can react not only differently, but sometimes in the complete opposite manner predicted."

Zeringue will next work to understand the underlying factors that govern network communication and stimulation, such as the various electrical pathways between cells and the genetic makeup of individual cells.

Provided by University of Pittsburgh

5 /5 (2 votes)

Related Stories

Astrocytes affect brain's information signaling

Jun 14, 2010

Astrocytes are the most common type of cell in the brain and play an important role in the function of neurons - nerve cells. New research from the University of Gothenburg, Sweden, shows that they are also directly involved ...

Study: Theta rhythm reduces seizure rate

Jun 20, 2006

Texas scientists say the brain's septum helps stop epileptic seizures by inducing electrical activity in another area of the brain called the hippocampus.

Neural modeling helps expose epilepsy's triggers

Feb 16, 2009

(PhysOrg.com) -- A brain scan of a person experiencing an epileptic seizure looks like the Great Plains during an early evening in midsummer. Fierce electrical storms pop up seemingly at random, proliferate ...

Stem cells are good for the brain

Jul 15, 2008

For some years, scientists have been speculating over why stem cells exist in the brain, as brain regeneration is limited. A German team of neuroscientists believe these stem cells help keep the brain healthy and active.

Recommended for you

Growing a blood vessel in a week

Oct 24, 2014

The technology for creating new tissues from stem cells has taken a giant leap forward. Three tablespoons of blood are all that is needed to grow a brand new blood vessel in just seven days. This is shown ...

Testing time for stem cells

Oct 24, 2014

DefiniGEN is one of the first commercial opportunities to arise from Cambridge's expertise in stem cell research. Here, we look at some of the fundamental research that enables it to supply liver and pancreatic ...

Team finds key signaling pathway in cause of preeclampsia

Oct 23, 2014

A team of researchers led by a Wayne State University School of Medicine associate professor of obstetrics and gynecology has published findings that provide novel insight into the cause of preeclampsia, the leading cause ...

Rapid test to diagnose severe sepsis

Oct 23, 2014

A new test, developed by University of British Columbia researchers, could help physicians predict within an hour if a patient will develop severe sepsis so they can begin treatment immediately.

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Jaeherys
5 / 5 (2) May 25, 2011
Wow that is cool! I really hope I am around when we finally understand how the brain works. It feels as if we are getting to a point where it will start to snowball even more. As methods for watching brain activity become closer and closer to real-time, our understanding of the mechanics behind the network will significantly increase.