The February 2023 issue of IEEE Spectrum is here!

Close bar

Laser Probes for Brain Experiments

Laser-activated probes stimulate brain cells better, say scientists

3 min read

19 May 2009—Understanding how the brain works typically involves sticking sharp metal electrodes into an animal’s brain and zapping its neurons with electricity. But researchers at Case Western Reserve University, in Cleveland, are working on what could be a more benign, efficient, and effective way to study brain circuits: using light.

The researchers have created a new kind of brain probe by coating the inside of a tiny hollow glass needle with nanoparticles of lead selenide, a semiconductor commonly used in infrared detectors. They insert the needle tips into slices of rat brains and shine infrared light from an 830-nanometer-wavelength titanium-sapphire laser on the probes. The nanoparticles absorb photons and generate an electric field that stimulates neurons, whose signals are recorded using another electrode placed next to them.

Keep Reading ↓Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions
Illustration showing an astronaut performing mechanical repairs to a satellite uses two extra mechanical arms that project from a backpack.

Extra limbs, controlled by wearable electrode patches that read and interpret neural signals from the user, could have innumerable uses, such as assisting on spacewalk missions to repair satellites.

Chris Philpot

What could you do with an extra limb? Consider a surgeon performing a delicate operation, one that needs her expertise and steady hands—all three of them. As her two biological hands manipulate surgical instruments, a third robotic limb that’s attached to her torso plays a supporting role. Or picture a construction worker who is thankful for his extra robotic hand as it braces the heavy beam he’s fastening into place with his other two hands. Imagine wearing an exoskeleton that would let you handle multiple objects simultaneously, like Spiderman’s Dr. Octopus. Or contemplate the out-there music a composer could write for a pianist who has 12 fingers to spread across the keyboard.

Such scenarios may seem like science fiction, but recent progress in robotics and neuroscience makes extra robotic limbs conceivable with today’s technology. Our research groups at Imperial College London and the University of Freiburg, in Germany, together with partners in the European project NIMA, are now working to figure out whether such augmentation can be realized in practice to extend human abilities. The main questions we’re tackling involve both neuroscience and neurotechnology: Is the human brain capable of controlling additional body parts as effectively as it controls biological parts? And if so, what neural signals can be used for this control?

Keep Reading ↓Show less
{"imageShortcodeIds":[]}