Sticking sharp, pointy metal needles into your brain is never an idea for a good time (image, deep brain stimulation). Future successful developments in neurotechnology, however, will be dependent on discovering ways to directly access our neurons without damaging surrounding brain tissue.

The mechanisms of how neural stimulation affects a human is still largely misunderstood, but therapeutic deep brain stimulation is used to relieve symptoms in patients with Parkinson's Disease, dystonia (a disorder involving continuous muscle contraction), and even severe cases of depression. This technique is still highly experimental and carries risks from the invasive nature of implanting electrodes into your brain.

Although still invasive, a new approach is being developed at Case Western Reserve University by the Strowbridge Lab, where a specially coated glass needle containing tons of metallic nanoparticles is inserted into the brain. Typically, electrical wires are needed to connect to implanted stimulating devices, but these nanoparticles are designed to generate electric fields when illuminated by infrared laser light (at 830 nm wavelength). No wires needed, just a non-invasive laser zap. The infrared wavelength is a useful selection because it easily passes through brain tissue, but can then be absorbed by the nanoparticles and re-radiated as an electric field.

Another key advantage to this technique is that the tiny electric fields from the particles will superimpose and extend out into the surrounding tissue stimulating the neurons in the field's wake to either generate their own electrical signals or possibly suppress their activity. The range of this wireless approach allows for a broader swath of neurons to be affected, whereas direct electrode stimulation can only influence a small cluster of nearby cells.

Indirectly activating neurons with laser light has been performed on cells in culture (read more), but this is the first attempt at working in actual brain tissue. So far, these experiments are applied only to extracted tissue from rat brains, but it is an important first step toward developing the technology further to learn how to best apply it into a living brain.