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This Defense Intelligence Reference Document was produced by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications program and dated 23 March 2010. It surveys noninvasive and invasive brain-machine interface technologies, including EEG, MEG, fMRI, NIRS and implanted electrode arrays, that could control external devices without limb-operated interfaces. It concludes that noninvasive electrical monitoring is the most promising near-term approach. For the long term it favors invasive single-neuron cortical connections.
From the source:Release of 2026-09-18 Incident: 3/23/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys brain-machine interface technologies intended to allow users to control external devices without conventional manual controls, and it evaluates both noninvasive and invasive approaches for turning neural or related physiological signals into usable commands. The report reviews the underlying neural signals, distinguishes between open- and closed-loop control systems, and examines technologies including scalp-based electrical recording, magnetic and imaging-based methods, and implanted cortical interfaces, with particular attention to bandwidth, response time, signal quality, and practical usability. It concludes that, in the near term, the most practical systems are likely to be noninvasive electrical approaches that draw heavily on muscle and neural signals, while longer-term high-bandwidth control would likely require more advanced invasive interfaces capable of robust two-way communication with individual neurons. The document presents thought-based control of external devices as a research field with plausible assistive and specialized applications, while emphasizing that naturalistic, high-performance control remained constrained by major technical and physiological limits.
UNCLASSIFIED//POlt OPPIEIAL U.!I! 01\LI EMG interfaces for limb amputees have advanced dramatically in the last severa l years, with several devices controlled by remain ing muscles that have been implanted with otherwise unused nerves in an invasive process called reinnervation (References 56, 57). Twelve electrode pa irs were utilized in the recording of intended arm motion . The classifier algorithm used to determine hand control was able to provide a new prediction 10 t imes a second, and for controls, a motion selection from 1 of 10 possibilities could be achieved in less than 170 milliseconds. Interesting with this procedure is that a direct biological amplification of the neuronal signal is achieved by connecting it to a muscle. The amplified signal is then read by a noninvasive EMG probe. Although not yet approaching normal, the speed and dexterity of these artificial limbs is impressive. Finally, one trial utilizing a normal, healthy human self-experimenter in 2002 showed that sensation and control is possible through a peripheral array implant in the median nerve of the left arm. This trial lasted 3 months before the physical connection between the nerve and the microarray deteriorated beyond use. Subsequent examination and testing has revealed no long-term damage at the implant site (Reference 58). OPTICAL STIMULATION OF ACTION POTENTIALS A final invasive technology that utilizes light to gate action potentials shows promise (Reference 59). In this technology, the biological switch is controlled by a locally inserted LED and poss ibly guided using optical fibers, but there is no contact between the physical circu its and neurons, thus avoiding the issue of scar tissue caused by operation of invasive probes. Application to artificial vision have al ready interesting pre clinical results in rat brain tissue (Reference 60). Discussion Any successful BMI hardware technology relies on at least one, and in most cases all, of the follow ing three essential elements: brain plasticity through user training, neural decoding by a machine learning algorithm, and neuroscience knowledge. Advances in the latter two will help all BMI research paths, but the former element is the most research path dependent since different technologies have different train ing limitations such as the inherent visual feedback delay of a noninvasive BOLD monitor. One approach to the training issue is to greatly simpl ify the control information bandwidth required. Research here has placed a focus on scenario-based controlling that is not from millisecond-to-millisecond updating of some 3-D trajectory like a full duplex BMI specified in the introduction would perform, but rather is controlled by high level commands from the user in a low-bandwidth supervisory mode. It is conceivably useful to tell a wheelchair to "Go Left," "Stop," or "Veer Right," and let sensors and actuators on the wheelchair work out the trajectory deta ils, as opposed to constantly setting and resetting the trajectory of the wheelchair. In this manner, much of the feedback error-correction is done in the physical circuit. Th is approach can be viewed as a series of simple asynchronous decisions, and relies on the artificial intelligence of the execution algorithms rather than tapping the general adaptability of mammalian brain architecture. Mention is made of this research path because it is important to the advancement of the field as a whole, though the concentration in th is treatise is on tapping the plasticity of neural systems rather than creating a program to im itate them . UNCLASSIFIED/ ,'FOR OFFI@IAl WSE OHlY 23
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 36 pages are in the text index: search them above, or from the library's search.