Defense Intelligence Reference Document Technological Approaches To Controlling

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rotate the platform supporting the fish. The lamprey was able to stabilize the hybrid
system, and this compensatory effect was most efficient in combination with undulating
swimming motions. The experimental setup is seen in Figure 13. These studies
demonstrate the feasibility of closed-loop interactions between a specific region of the
nervous system and an artificial device. Closed-loop brain-machine interfaces offer an
unparalleled opportunity to investigate how plastic changes can be guided by
modulating the input signals of the neurons based on the behaviors generated by the
output of the same neurons. Furthermore, in such hybrid systems it is possible to
replace the neural tissue with a computational model, thus providing a direct means for
testing the predictions of specific hypotheses about neural information processing.
Adaptation to the variable dynamics of the limbs and of the limb environment has
generated an increasing volume of research that is relevant to brain-machine
interfaces.
TRIALS USING HUMAN SUBJECTS
Testing BMis on normal human subjects presents ethical dilemma since any volunteer
outside of the research team itself would likely have difficulty understanding all of the
risks involved in neural implantation. Even well-known volunteers such as Jans
Naumann now admit they truly did not understand the risks involved and are
considering having chronic implants removed. 19 Not all human trials have produced
such poor results.
Significant ECoG arrays are implanted in epileptic patients prior to surgery to provide
high resolution spatial localization of seizure activity (Reference 45). In these clinical
tests, the arrays are implanted in the patient and then monitored until seizures takes
place. This procedure can take more than a week and the patient has little to do
between random onsets of seizure activity. Epilepsy is generally considered a localized
pathology, almost always lateralized to the right or left lobe. The remaining brain
networks, especially from the nonseizure half of the brain, are generally normal. This
provides an opportunity for cohort cognitive studies since they represent minimal
additional risk for volunteers undergoing the procedure as a medical necessity. Blakely
et al. utilized such a patient to decode brain network patterns associated with different
English phonemes (Reference 52). Mapping all of the phonemes could constitute an
open-loop technology to communicate without speaking using normal language instead
of learned motor patterns. Schalk and colleagues utilized a sample of five pre-surgical
epileptics to demonstrate ECoG to control one- and two-dimensional cursor movement.
Movement times to target were on the order of 1-2 seconds with up to 75 percent
accuracy with training time on the order of 30 minutes or less (Reference 53).
Spinal cord injury (SCI) is another clinical condition where the normal brain is intact
and ECoG arrays may be implanted for testing a neuroprosthetic. Researchers in
Toronto recently reported good hand movement and grasping control using ECoG
arrays (Reference 54). Similarly, Hochberg showed good results in 2-D cursor control,
but still seconds or more slower than a mouse control, even after 90 days of training. A
following task was more successful, though the accuracy for use in fine manipulations
needs improvement (Reference 55).
19 Jans Naumann was the first recipient of a second-generation artificial vision system (AVS) designed by the
Dobelle Institute. The AVS project was based in New York, but the procedures themselves were conducted in
Lisbon, Portugal, to avoid U.S. prohibitions against implant surgery.
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