Our brain as an example

Photo: Bart van Overbeeke
Photo: Bart van Overbeeke
TU/e researcher Imke Krauhausen built new electronic devices based on neuromorphic computing

Our brain can process complex information at lightning speed using very little energy. This is why there is rapidly growing interest in the human brain as a model for the development of new computer technology. TU/e researcher Imke Krauhausen built new electronic devices based on neuromorphic computing. By using organic materials, she hopes that her artificial synapses will eventually be used for applications in the human body. On Wednesday April 10th, Krauhausen defended her doctoral research cum laude at the Department of Mechanical Engineering.

(Written by Nicole Testerink)

As a young child, she mainly played with Playmobil, Krauhausen explains somewhat regretfully. "It’s only now that I’ve discovered how much fun Lego really is."

At the beginning of her PhD track, she found herself diving into a giant container of building blocks to assemble a robot designed to help her with her experiments. Krauhausen wanted to see if she could teach this robot to navigate a maze.

But the most remarkable part is inside the robot itself: it is controlled by a neuromorphic circuit. "In the lab, we developed artificial synapses - flexible connections that enable the individual neurons in our brain to communicate with each other. We make these synapses with organic polymers that the human body can tolerate. Because eventually, we want to start using them for applications within the body: a smart prosthesis or a sensor capable of adapting inside your body."

Super-efficient

For some time now, researchers have been studying the functioning of our brain as an example for the development of a new generation of computer systems.

Since we are increasingly using smart devices and artificial intelligence, we also need new, and above all, more energy-efficient computer technology, Krauhausen explains. "And our brains are very good at that. They use a mere 20 watts per hour for very complex tasks, something even the most ingenious supercomputer is nowhere near achieving. Our brain is a great source of inspiration."

Whereas traditional computer chips consist of silicon and metal, TU/e research group Neuromorphic Engineering is working on an organic system based on water and salt, just like our brains. There, synapses can transmit electrical signals thanks to an ingenious system of salts and salt-gated channels.


The electronic circuits used by Krauhausen also have such a salt channel. "A very small one, though, think about 100 to 200 micrometers. So that meant a lot of microscopy work in the cleanroom. Within our group, we work with several researchers on different aspects of the same artificial neuronal system. This ranges from developing new organic materials and researching new algorithms to fine-tuning the device’s mechanical behavior."

Autonomous robot

The focus of Krauhausen’s research - a collaborative effort between TU/e and the Max Planck Institute of Polymer Research - is on the actual application of the artificial synapses developed in the lab. She reaches for her dissertation in which she has fleshed out three examples in detail; this was partly done in Germany. "I started by training a single artificial synapse, in the Lego robot. It had to learn how to find the exit of the maze by itself."

"I showed the robot pieces of brightly colored paper: turn left when you see this signal, right when that signal is absent. In the end, the robot was able to find its way through several mazes all by itself. These are first steps for applications such as a rescue or space robot; any situation where a robot needs to be able to act autonomously and adapt to a new environment, but where a large battery isn’t practical."

PHD IN THE PICTURE

What is that on the cover of your dissertation?
"Together with the ICMS Animation Studio, we tried to capture the essence of my research in one image. On the back, you see a natural cerebral hemisphere connected to all kinds of intertwined neurons; that same hemisphere and neuronal network can be seen on the front, artificially constructed with electronics.

You’re at a birthday party. How do you explain your research in one sentence?
"I’m trying to replicate the functioning of our brain with an organic device for the development of new complex and energy-efficient applications."

How do you blow off steam outside of your research?
Spinning, cycling, hiking, and bouldering; I love exercising my brain in other ways. But I also thoroughly enjoy a good cup of coffee with a piece of cake."

What tip would you have liked to receive as a beginning PhD candidate?
"
You have to do it yourself, so be as proactive as possible. Talk to people, ask lots of questions and try to find your own path."

What is your next chapter?
"While I certainly don’t want to have everything set in stone, it’s nice to have some long-term prospects. A place in academia often involves a lot of competition and moving. I feel I’ve had enough of that recently, especially the latter, and I like it just fine in Eindhoven. Besides, I’d like to see how the ideas from the lab are put into practice in the "real world". For truly applied research, I’d rather look for an R&D position in industry now, but everything is still wide open."

Hot and cold

In a follow-up study, Krauhausen made the transition to a device with two artificial synapses, a robotic arm. This arm has a 3D-printed hand, made of a very soft and flexible material. A potential interactive prosthesis, Krauhausen points out for a future application. She used multiple sensor types to allow the robotic hand to feel the difference between hot and cold.

In the first few training sessions, the hand was supposed to pick up a cup. It worked, Krauhausen recounts enthusiastically. "After that, the experiments became more exciting. We spent a long time training the hand to distinguish between cold and hot surfaces. It was a real victory when, in an experiment, the hand avoided the cup of hot tea - ouch, dangerous - but instead, grabbed the cold cup."

Her findings mark a significant technological advancement in intelligent robotics. And this is being recognized, as it has just been announced that they will soon be published in leading scientific journal Nature Communications, an elated Krauhausen informs us.

In the third study, Krauhausen tried to scale up the system even further by simulating a network of artificial synapses capable of predicting blood glucose levels.

"The current system is as follows: a patch on your skin communicates with your smartphone or the cloud to monitor blood sugar levels allowing the patient to manually make a next prediction. But thanks to the use of artificial synapses, the computer calculations for glucose prediction could also be done locally on the skin. We were able to demonstrate that the algorithms executed by our artificial neural network were just as effective as with the traditional software network."

New architecture

Krauhausen’s work successfully demonstrates the practical applications of organic artificial synapses outside the lab for the first time. But in order to realize actual products in the future, a lot of development is still needed, especially in the area of algorithms, she emphasizes.

"Of course, follow-up steps need to be taken in terms of the device itself. But that aside, this is really an entirely new form of computing. We have to let go of the traditional system architecture, and many new algorithms are needed. So it’s a highly multidisciplinary project, which is why we’re very happy to be part of the ICMS (Institute of Complex Molecular Structures, Ed.). It requires the collaboration of a wide range of researchers, from chemical engineers, mechanical engineers, material experts and soft robotics engineers to mathematicians and IT specialists. We had to learn to speak each other’s languages and find a common ground to keep sight of the big picture. But in the end, many bridges were built". She laughs. "Including ones made of Lego."