Documents / Official release
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/ /FOR 8FFI€iIAL YSE 8,.LV currently 22 electrodes directly implanted into the cochlea of the inner ear. The microphone and sound processor replaces the outer and middle ear, while the electrodes replace the frequency selective hair fibers of the inner ear that normally would transmit electrical signals to the cochlea. The quality of the sound is much less than natural hearing, but the only option for patients who have lost hearing or were born deaf. It has been estimated that 100,000 cochlear implants provide sound to users worldwide (Reference 37). The cochlear implant is an open loop stimulation system that provides complex signals to the nervous system through a peripheral connection. BMI technologies have evolved from assistive technology devices solely targeted for the healthcare industry, into apparatuses designed for intracortical microstimulation to deliver sensory feedback. Such systems allow the simultaneous recording and microstimulation of neuronal and behavioral events. The primary device that has emerged leading this technological transformation is the direct cortical array containing either surface or neocortex penetrating electrodes. The direct cortical array is implanted on the surface of the brain near the functional area of interest, and then the connection is reverse-engineered: individual electrodes are tested to determine if they should be assigned as input, output, or neither. 12 These devices are designed to fuse neural signaling pathways with external machinery into a 3D control system, such as those apparatuses designed to modulate the movement of appendages (e.g. robotic arms), though the signals could be used for control of any complex machine. The control circuits on these systems are intricate and often bulky, and they can be designed with either open- or closed-loop sensory feedback. An additional device is the penetrating cortical electrode. These electrodes contain a ladder of input/output probes and can be selected to transmit or receive signals in any layer of the neocortex. Research is ongoing regarding the optimal layer with which to place an interface. When using penetrating electrodes, tissue response is an additional challenge as these devices frequently cause scarring. Animal studies are in progress to quantify this effect. Technological challenges in development of all types of invasive BMI devices include signal decoding/stimulation algorithms, and localization of brain activation near the implant. Functional MRI (fMRI) is utilized in conjunction with the invasive implants to confirm additional neural network activity during interface tasks. Modifications in the design of electrodes is necessary for experiments in volving fMRI (Reference 38). 13 The majority of invasive experiments to date use animal or even tissue models, though a few human trials have been conducted (with the exception of the cochlear implant described above) . OPEN-LOOP DIRECT CORTICAL ARRAY ALGORITHM MODELING In traditional open loop experiments, eye movement systems are utilized to develop a linear model for a physiological system. 14 In such experiments, invasive signals are recorded from the cortex and the motion of the eye is recorded in tandem. The location t i This procedure eliminates the need to directly locate the neuron(s) of interest during implantation . 13 Field potentials at the points of metal electrodes cause concentration of RF energy from the excitation pulses of the MRI. Th is effect is used in a similar setup for tissue ablation therapy; however, such energy concentration is undesirable in the studies at hand . 1• These techniques may be generally applied to any motor control systems. UNCLASSIFIED/ /FOR. 8fPltlAL U.91!! f>flt I 11
Not linked to a story yet.
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.