Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

Silicon on the Brain
A chip that reads neurons

Context: The neurons of the mammal brain are hard to study, even when they’re isolated in the lab. For more than a decade, scientists have analyzed the large neurons of leeches and snails by linking them directly to silicon chips that record their electrical activity. But mammalian neurons are smaller, and though they can be grown on silicon, the resulting signals are typically too weak to yield useful data. The electrical activity of mammalian brain cells can be read with electrodes, but that can be imprecise and requires careful preparation steps.

Moritz Voelker and Peter Fromherz at the Max Planck Institute for Biochemistry have now designed the first computer chip that can record the firing of mammalian neurons, though so far only in a petri dish.

Methods and Results: As a neuron fires, the voltage across it changes, so a neuron on a chip affects how transistors underneath it conduct electricity. But in chips with conventional transistor designs, there’s so much naturally occurring noise that it swamps neural signals. So Voelker and Fromherz changed the geometry of the transistors to suit the electrical properties of living neurons. They buried the conducting channels of their transistors a few nanometers deeper than usual, making the transistor more sensitive to the low voltages and firing speeds of neurons. The transistors could detect the signal of an ­individual rat neuron in a group, without the elaborate sample preparation that ­conventional electrodes require. What’s more, the tran­sistors are significantly smaller than individual neurons and could in principle provide information on how subsections of a neuron behave.

Why it Matters: Electrodes implanted in human brains have allowed paralyzed patients to move computer cursors and prosthetic limbs (see “Implanting Hope,” March 2005, p. 48). While increased computing power helped enable that breakthrough, so too did the development of hardware suitable for detecting neural signals. A silicon interface could process data more nimbly and is the logical candidate for next-generation devices. Those are still years away; in the nearer term, neuron-silicon interfaces will help explain how groups of neurons communicate with each other and could be particularly helpful for understanding how neuroactive drugs such as antidepressants work.

Source: Voelker, M., and P. Fromherz. 2005. Signal transmission from individual mammalian nerve cell to field-effect transistor, Small 1:206–210.

0 comments about this story. Start the discussion »

Tagged: Biomedicine

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me
×

A Place of Inspiration

Understand the technologies that are changing business and driving the new global economy.

September 23-25, 2014
Register »