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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 23 March 2010, was produced under the Advanced Aerospace Weapon System Applications (AAWSA) Program. It surveys invasive and noninvasive brain-machine interface technologies for controlling external devices without limb-operated interfaces. The technologies covered include EEG, MEG, fMRI, NIRS, and implanted electrode arrays. It concludes that noninvasive electrical monitoring is the most promising near-term approach. In the long term, it favors invasive single-neuron cortical connections that use optical stimulation or chip-based arrays.
“The Times”18 pages
UNCLASSIFIED/;'P81il 8PPll!ltllt ~81!! 8HLV NONINVASIVE MAGNETIC DEVICES Detection of magnetic fields arising from neural activity using MEG or a future technology have the same inherent limitations as EEG-only noninvasive sensors. Resolving these signals from background in any naturalistic environment will not occur without the development of a disruptive technology in shielding that is portable and lightweight enough to be worn comfortably on the head, and will attenuate background amplitude nearly 10 orders of magnitude across the entire range of neural signal frequencies, and the entire range of frequencies where the detection electronics may be sensitive. Body-temperature superconducting materials may accomplish the shielding if engineering development continues, and these could be combined with atomic magnetometer technology to produce a portable system, though the inherent limitations of the method will still be present. INVASIVE TECHNOLOGIES - GENERAL, OPTICAL, AND EX-VIVO ENGINEERING All invasive technologies will have to undergo substantial rigorous testing to determine the long-term side-effects of implantation and operation, as well as drift in the operational performance with extended use. Several pre-clinical devices detailed above and discussed below show promise, but the handful of human trials show that direct interface technologies based on proximal action potential stimulation and detection are still a long way off from practical application since the trials themselves in duplex operation show functional failure after only a matter of weeks. The mammalian auditory system is well studied, and the cochlear implant has been in use and continued development for more than 30 years, and there is yet to be any practical application for implanting a cochlear device into a normal healthy individual. Proximal electrode interfaces do not appear to be the answer for high bandwidth BMI, and further development in the machine-biology contact is required. If the 30-year advancement of cochlear is a realistic guide of innovation, the proximal electrical technology path to success is 30-40 years off save for a disruptive advance in the development of penetrating electrodes. Two invasive research paths that are promising are optical stimulation and gating, and ex-vivo growth of neural cells on physical circuits. The advantage of optical stimulation and gating is that one could theoretically design an optical link to act as a connected input dendrite on a single neuron. Theoretically, one should also be able to use spectroscopic sampling to determine if an action potential is progressing down an axon, thus providing a single neuron output (read or monitor) capability as well. This invasive but noncontact full-duplex information channel would effectively hook-up the physical computer seamlessly to the network structure of the brain. Proof of principle studies in this technology could emerge at any time, and given the demonstrated plasticity of neural networks in both closed-loop visual feedback and lamprey experiments, could provide a disruptive path for advancement of BMI. The ex-vivo growth of neural tissue on electrode arrays provides a controlled platform for: • Testing long-term effects of electrode use on proximal neural tissue. 26 UNCLASSIFIED/ ,<EiOAt OEiEiIQl.ltk Wlili &••LY
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 36 pages are in the text index: search them above, or from the library's search.