Month: June 2009

BrainGate Enters Round 2 of Clinical Trials

The BrainGate collaboration, lead by Dr. John Donoghue from the Department of Neuroscienceat Brown University, recently announced they have began recruiting patients to join in the clinical trials of the second iteration of their neural interface system.

The first round of trials was run by Cyberkinetics, an independent neurotech company founded by Dr. Donoghue, but they have pulled out of this next phase due to funding difficulties. Now, a purely academic team based at the Massachusetts General Hospital, these exciting trials will help guide the next generation of neurotechnological interfaces between human brain activity and direct actions on a computer and, eventually, control of prosthetic devices.

The near-term goal of this research is to develop a technology that can assist patients with degenerative neurological paralysis where their brain is trying to talk to its body, but the body just isn’t listening. The BrainGate system trains itself to decode electrical activity in the brain and translate recorded signals into a computer for control of an external device. In effect, BrainGate is a bridge that re-routes neural communication to a device that would be designed to replace lost function.

With previous work, the critical success was converting brain activity into the control of a cursor on a computer screen. Although this seems to be a trivial activity, the understanding of the neuroscience behind the actual relationship between specific brain activity and the mechanical control of our environment remains a vital bit of understanding required for the future of neurotechnology. Now, with the BrainGate2 trials starting soon, opportunities to discover new science will hopefully bring us closer to successful devices for assisting patients with ALS, spinal cord injuries, stroke patients, and many others with empowering technologies to live their lives to the fullest.

“Brain-computer interface begins new clinical trial for paralysis” :: EurekAlert :: June 10, 2009 :: [ READ PRESS RELEASE ]

Interfacing with Electrocorticography

Recently, we discussed the developments from the Wadsworth Center of a minimally-invasive, thin-film technology to enhance electrocorticography (ECoG) recordings (read). Similar to the more common electroencephalogram (EEG) method, which uses an array of electrodes stuck on your outer skull to receive electrical signals from your neurons, the ECoG uses an array of electrodes embedded just on the surface of your brain allowing for a more direct electrical view of neural activity. This view still covers an averaged signal from a large number of talking neurons and still does not see individual electrical signals. However, by having the bony skull out of the way, the electrodes sure have a more clear shot for picking up the electric fields.

The importance of this work from Wadsworth is that the brain and it’s violent bodyguard, the immune system, doesn’t really like to have things hanging around that the body didn’t make on its own. So, typical implanted devices will quickly be destroyed by attacking antibodies. Here, the specialized implanted ECoG devices are lasting six to twelve months in human patients, but their goal is to improve the device life-cycle to five to ten years.

Through their collaboration with clinical neurologists and biomedical engineers at Washington University in St. Louis, Missouri, the Wadsworth group, lead by Gerwin Schalk, is taking the technology to the next step by integrating the recording activity with specialized software that maps the brain activity with computer control. The implanted ECoG providing its more detailed map of brain activity allows for a specific correlation to be observed between physically clicking a computer mouse button, for example, and the resulting pattern of neural firings in the brain. The patient can then train their thoughts to reproduce similar neuron activity and, with a direct connection to the computer, the mouse click appears without the click.

The interfacing process is being licensed to a start-up company in St. Louis called Neurolutions, who will be working to improve the software and training process to bring it to market for applications in neuroprosthetics. The challenge for further advancement begins with the unfortunately situation that just clicking a mouse button doesn’t get us very far in life. Just moving fingers and arms requires multi-dimensional spatial control, and with that comes an an unknown number of different neural patterns being required to simply raise your arm to reach the mouse on top of the desk. All of the corresponding neural activity–move shoulder up, rotate elbow, lift index finger, shift arm to the right, etc.– will need to be mapped, trained, and accessed to control a prosthetic device… and each human might have different neural patterns for the same physical motion.

“Reading the Surface of the Brain” :: Technology Review :: June 3, 2009 [ READ ]

“Brain-Computer Interface Technology Licensed to Missouri Firm” :: NY State Dept. of Health Press Release :: March 25, 2009 :: [ READ ]

Illuminating Your Thoughts

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 Diseasedystonia (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.

“Laser Probes for Brain Experiments” :: IEEE Spectrum :: May 19, 2009 :: [ READ ]

Last updated April 5, 2020