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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.
UNCLASSIFIED/;«F&A 8FFISWI1k YE'lii 8111 Y Figure 9. Image Distortion and Custom Microwire Electrode Assembly to Improve It. (A) Image distortion induced by metallic bone screws and connectors. No feature can be identified. Spin echo sequence: TR=1s, TE=6.75ms, NT=4, Matrix=128x128. FOV=60x60mrn 7 • Experiment time=512 s. (B) (Top) Microelectrode array used in the study. (Bottom) Close-up of the connector piece that was constructed for multiple connection/disconnection cycles. Interface piece to connect the nano-miniature Omnetics connector of the head stage with the head-cap-embedded custom connector for extraceIIuIar muItiunit activity monitoring. (C) Improvement in image quality after replacement of bone screws and connectors with compatible equivalents. TR=3500ms, TE=20ms, averages=2, acquisition matnx=128X96, FOV=21x21mm2, slice thickness=0.4mm, total acquisition time (TA)=672sec, resolution=164μmx220μm. (Reference 51) With this system, the authors successfully recorded spontaneous extracellular multiunit neural activity in 16 electrodes (four in each animal) for 6 weeks post-implant. Of those 16 electrodes, 12 registered data verifying distinct neural activity prior to MR exposure. To determine the overall effectiveness and feasibility of this procedure, a tissues damage assessment associated with the MRI was conducted by utilizing T2 maps from tissue dissections (Figure 10). Thorough examination of the electrode location and resultant tissue survivability revealed little damage from the operation of the BMI. The locations of the microwires are visible as dark lines in the image (indicated by ovals). ·.A: Figure 10. Example of T2 Variability. (A) T2 maps from MRI rat 16 at day 7 post-implant show elevated vaIues proximal to the implant location (circled). (B) T2 maps from MRI rat 18 at day 30 post-implant shows no difference between the implant and control hemispheres. TR=3500ms, TE= 10, 20, 30, 40, 50, 60ms, averages=2, acquisition matrix=128x96, FOV=21x21mm 2, slice thickness= 0.4mm, TA=75mins, resolution=164μmx220μm. The ovals indicate the site of electrodes. (Reference 51) 19 UNCLASSIFIED/ /F81it 8FFI&I.«1k W&lii OllkY
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Report, from the dia 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.