AAWSAP DIRD, Technological Approaches to Controlling External Devices, March 2010

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.

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microelectric design of chronic neural implants. In 2006, Fetz et al. illustrated an
intracranial operated neural implant that could function as neural prosthetic to assist
upper limb movement for individuals that suffered from spinal cord injuries. The
intriguing part of the Fetz design is its ability to function as an autonomous battery
operated device. This is a departure from traditional BMI devices that are cumbersome
and difficult to operate. Clearly this is a step forward in the development of microwire
electrode design applications (Reference 44). Figure 5 illustrates the schematic flow
chart of the Fetz MEMS neurochip, also called a programmable system-on-chip (PSoC)
architecture.
Programmable System on Chip Architecture
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Figure 5. Schematic of the Neurochip Functional Blocks. Parallel PSoC microcontrollers record neural and
muscle signals to independent memory modules. Primary PSoC also controls a constant-current stimulator circuit
and communicates via IR to a PC or hand - held PDA. (Reference 44)
Traditional PSoC designs operate on a high power consumption and short battery life of
radiotelemetry systems (Reference 46). In the Fetz study, researchers implanted
electronic devices that collected data in unrestrained monkeys. The system operated
without the power limiting and cumbersome restraints exhibited by these previous
systems . For this design, an onboard spike processing and a stimulator circu it were
employed to allow for real-time bidirectional interface with the nervous system. After
several modifications, Fetz et al. successfully created a device that was able to
simultaneously record electromyogram (EMG) activity and neural activity at the
implant. The lithium battery operated power source and electronic data systems were
skillfully packaged within a compact percutaneous (inner skin) titanium casing that was
attached to a monkey's skull; the entire implant weighed only 56 g. Neural data was
acquired from 12 microwire electrodes chronically implanted in the primary motor
cortex. Leads run subcutaneously from the head casing to a connector on the monkey's
back. Two pairs of stainless-steel wires were inserted percutaneously into the forearm
muscles where they were attached to an EMG signal recorder (Reference 44).
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