Inhibitory nodes in self-assembling networks mimic the human brain

Our brains are incredibly plastic—able to change as we learn and grow older, able to recover from injury and remap functions around damage. These changes are thanks to the fact that the brain’s synapses can strengthen when cells at the ends of those synapses fire in sequence more frequently.

But in a healthy brain, particular signals that travel over the synapses must also sometimes be slowed or stopped. Inhibitory neurons keep those impulses in check and destroy unused synapses.

Wire formed at ΔV = 25 kV showing a typical wire at zero transverse field and the deformed wire after the transverse field is switched on.
Wire formed at ΔV = 25 kV showing a typical wire at zero transverse field and the deformed wire after the transverse field is switched on.
Recent work by University of Illinois physicist Alfred Hubler and doctoral student Cory Stephenson shows that this same break in the action can occur in self-assembling networks of wires. By exposing these wires to an electrical field that runs across the current traveling through the wire, they showed for the first time that these self-assembling systems could form inhibitory nodes and destroy undesirable connections.

The research paper, “Stability and conductivity of self assembled wires in a transverse electric field,” was published this week in Scientific Reports.

“Inhibitory nodes are very important,” Hubler said. “They’re basically a resistor that changes conductance whether that’s in an electrical system or a brain.”

With these resistors in place, Hubler said researchers are one step closer to designing “engineered brains,” which could someday be built to independently solve any number of problems.

“Every biological system is also a physical system. Biological systems are constrained to certain conditions—a human must breathe oxygen and live in a very narrow temperature range—that engineered systems don’t face,” Hubler said.

“We can engineer a probe to fly to the moon, Pluto, even exit the solar system, but a bird can’t do that.”

Hubler’s work is supported by the Defense Advanced Research Projects Agency’s Physical Intelligence program. It explores “intelligence engineered from first principles” to create “new classes of electronic computational, and chemical systems.” As part of the program, Hubler and Stephenson also worked with chemists at Wake Forest University and psychologists and cognition experts at the University of Connecticut.
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Contact: Alfred W. Hubler, Department of Physics, University of Illinois at Urbana-Champaign, 217/244-5892, [email protected]

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