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'''Neuroprosthetics''' (also called '''neural prosthetics''') is a discipline related to [[neuroscience]] and [[biomedical engineering]] concerned with developing neural [[prosthetics|prostheses]].
'''Neuroprosthetics''' (also called '''neural prosthetics''') is a discipline related to [[neuroscience]] and [[biomedical engineering]] concerned with developing neural [[prosthetics|prostheses]].
Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. An example of such devices is [[Cochlear implants]]. This device substitutes the functions performed by the [[ear drum]], [[Stapes]], frequency analysis in the [[cochlea]] and stimulates the [[auditory nerve]]s directly. A microphone on an external unit gathers the sound and processes it, the processed signal is then transferred to an implanted unit that stimulates the auditory nerves through a [[microelectrode array]].
Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. An example of such devices is [[Cochlear implants]]. This device substitutes the functions performed by the [[ear drum]], [[Stapes]], frequency analysis in the [[cochlea]] and stimulates the [[auditory nerve]]s directly. A microphone on an external unit gathers the sound and processes it, the processed signal is then transferred to an implanted unit that stimulates the auditory nerves through a [[microelectrode array]].
The development of such devices has a profound impact on the quality of human life. Individuals that are practically isolated because of their disabilities will be able to enjoy the every day things we take for granted. The research in this field is meant to resolve these huge disabilities.
The development of such devices has a profound impact on the quality of human life. The research in this field is meant to resolve these huge disabilities.


There is another side to the application of neural prostheses. These implantable devices can also be used in animal experiments as a tool for neuroscientists in order to develop a better understanding of how the [[brain]] works. Wireless neuro recording from the brain of awake, freely behaving animals can open many important doors into understanding how the brain handles different functions. Accurately probing and recording the electrical signals in the brain would help better understand the relationship among a local population of neurons that are responsible for a specific function. In order to substitute sensory, motor or cognitive modalities, we need to first understand which part of the brain is responsible for those modalities and how those functions are performed. Neuro prosthetics and neuro science have a very intertwined relationship. Neuro prostheses contribute to better understanding of the neural system and this better understanding helps develop better, more application-specific neural prostheses.
There is another side to the application of neural prostheses. These implantable devices can also be used in animal experiments as a tool for neuroscientists in order to develop a better understanding of how the [[brain]] works. Wireless neuro recording from the brain of awake, freely behaving animals can open many important doors into understanding how the brain handles different functions. Accurately probing and recording the electrical signals in the brain would help better understand the relationship among a local population of neurons that are responsible for a specific function. In order to substitute sensory, motor or cognitive modalities, we need to first understand which part of the brain is responsible for those modalities and how those functions are performed. Neuro prosthetics and neuro science have a very intertwined relationship. Neuro prostheses contribute to better understanding of the neural system and this better understanding helps develop better, more application-specific neural prostheses.

Revision as of 22:26, 1 June 2009

Neuroprosthetics (also called neural prosthetics) is a discipline related to neuroscience and biomedical engineering concerned with developing neural prostheses. Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. An example of such devices is Cochlear implants. This device substitutes the functions performed by the ear drum, Stapes, frequency analysis in the cochlea and stimulates the auditory nerves directly. A microphone on an external unit gathers the sound and processes it, the processed signal is then transferred to an implanted unit that stimulates the auditory nerves through a microelectrode array. The development of such devices has a profound impact on the quality of human life. The research in this field is meant to resolve these huge disabilities.

There is another side to the application of neural prostheses. These implantable devices can also be used in animal experiments as a tool for neuroscientists in order to develop a better understanding of how the brain works. Wireless neuro recording from the brain of awake, freely behaving animals can open many important doors into understanding how the brain handles different functions. Accurately probing and recording the electrical signals in the brain would help better understand the relationship among a local population of neurons that are responsible for a specific function. In order to substitute sensory, motor or cognitive modalities, we need to first understand which part of the brain is responsible for those modalities and how those functions are performed. Neuro prosthetics and neuro science have a very intertwined relationship. Neuro prostheses contribute to better understanding of the neural system and this better understanding helps develop better, more application-specific neural prostheses.

In order to achieve these devices there are many challenges. Any implanted device has to be very small in order to be to minimally invasive, especially in the brain, eye, cochlea. Also this implant would have to communicate with the outside world wirelessly. Having wires sticking out of the head, eye, etc is not an option. Besides the discomfort and restrictions it would impose on the subject this could lead to infection in the tissue. This bidirectional wireless communication requires a high bandwidth for real-time data transmission; this is a great challenge considering that this data link has to operate through the skin. The minimal size of the implant means no battery can be embedded in the implant, the implant works on wireless power transmission through the skin which is equally challenging as the data transmission. The tissue surrounding the implant is usually very sensitive to temperature rise so the implant must have very low power consumption in order to assure it won’t harm the tissue. Another very important issue is the bio compatibility of the material that the implants are coated with. The more biocompatible these materials are the less tissue reaction they will cause thus resulting less implant risk and longer implant period.

Gradually as these devices become safer and the our understanding of how the brain works enhances the use of these devices will become more and more common and help people with severe disabilities live a normal life. The neuroprosthetic seeing the most widespread use is the cochlear implant, with approximately 100,000 in use worldwide as of 2006.[1]

Today, the use of cochlear implants and pacemakers has become an undeniable fact of life. The future holds an exciting prospect for the every day use of a variety of neural prostheses.

History

The first cochlear implant dates back to 1957. Other landmarks include the first motor prosthesis for foot drop in hemiplegia in 1961, the first auditory brainstem implant in 1977 and a peripheral nerve bridge implanted into spinal cord of adult rat in 1981.[2] Paraplegics were helped in standing with a lumbar anterior root implant (1988) and in walking with Functional Electrical Stimulation (FES).

Regarding the development of electrodes implanted in the brain, an early difficulty was reliably locating the electrodes, originally done by inserting the electrodes with needles and breaking off the needles at the desired depth. Recent systems utilize more advanced probes, such as those used in deep brain stimulation to alleviate the symptoms of Parkinson's Disease. The problem with either approach is that the brain floats free in the skull while the probe does not, and relatively minor impacts, such as a low speed car accident, are potentially damaging. Some researchers, such as Kensall Wise at the University of Michigan, have proposed tethering 'electrodes to be mounted on the exterior surface of the brain' to the inner surface of the skull. However, even if successful, tethering would not resolve the problem in devices meant to be inserted deep into the brain, such as in the case of deep brain stimulation (DBS).

Sensory prosthetics

Visual prosthetics

Main article: Visual prosthetic

A visual prosthesis can create a sense of image by electrically stimulating neuro cells in the visual system. A camera would wirelessly transmit to an implant, the implant would map the image across an array of electrodes. The array of electrodes has to effectively stimulate 600-1000 locations, stimulating these optic neurons in the retina thus will create an image. The stimulation can also be done anywhere along the optic signal's path way. The optical nerve can be stimulated in order to create an image, or the visual cortex can be stimulated, although clinical tests have proven most successful for retinal implants.

A visual prosthesis system consists of an external (or implantable) imaging system which acquires and processes the video. Power and data will be transmitted to the implant wirelessly by the external unit. The implant uses the received power/data to convert the digital data to an analog output which will be delivered to the nerve via micro electrodes.

Photoreceptors are the specialized neurons that convert photons into electrical signals. They are part of the retina, a multilayer neural structure about 200 um thick that lines the back of the eye. The processed signal is sent to the brain through the optical nerve. If any part of this path way is damaged blindness can occur.

Blindness can result from damage to the optical pathway (cornea, aqueous humor, crystalline lens, and vitreous). This can happen as a result of accident or disease. The two most common retinal degenerative diseases that result in blindness secondary to photoreceptor loss is age related macular degeneration (AMD) and retinitis pigmintosa (RP).

The first clinical trial of a permanently implanted retinal prosthesis was a device with a passive microphotodiod array with 3500 elements.[3] This trial was implemented at Optobionics, Inc., in 2000. In 2002 second sight medical products, inc. (Sylmar, CA) began a trial with a prototype epiretinal implant with 16 electrodes. The subjects were six individuals with bare light perception secondary to RP. The subjects demonstrated their ability to distinguish between three common objects (plate, cup, and knife) at levels statistically above chance. An active sub retinal device developed by Retina Implant GMbH (Reutlingen, Germany) began clinical trials in 2006. An IC with 1500 microphotodiods was implanted under the retina. The microphotodiods serve to modulate current pulses based on the amount of light incident on the photo diode. [4]

The seminal experimental work towards the development of visual prostheses was done by cortical stimulation using a grid of large surface electrodes. In 1968 Giles Brindley implanted an 80 electrode device on the visual cortical surface of a 52-year-old blind woman. As a result of the stimulation the patient was able to see phosphenes in 40 different positions of the visual field. [5]. This experiment showed that an implanted electrical stimulator device could restore some degree of vision. Recent efforts in visual cortex prosthesis have evaluated efficacy of visual cortex stimulation in a non-human primate. In this experiment after a training and mapping process the monkey is able to perform the same visual saccade task with both light and electrical stimulation.

The requirements for a high resolution retinal prosthesis should follow from the needs and desires of blind individuals who will benefit from the device. Interactions with theses patients indicate that mobility without a cane, face recognition and reading are the main necessary enabling capabilities. [6]

The results and implications of fully-functional visual prostheses are exciting. However, the challenges are grave. In order for a good quality image to be mapped in the retina a high number of micro-scale electrode arrays are needed. Also, the image quality is dependent on how much information can be sent over the wireless link. Also this high amount of information must be received and processed by the implant without much power dissipation which can damage the tissue. The size of the implant is also of great concern. Any implant would be preferred to be minimally invasive. [7]

With this new technology, several scientists, including Karin Moxon at Drexel, John Chapin at SUNY, and Miguel Nicolelis at Duke University, started research on the design of a sophisticated visual prosthesis. Other scientists have disagreed with the focus of their research, arguing that the basic research and design of the densely populated microscopic wire was not sophisticated enough to proceed.

Audio and even tactile sensation can be similarly induced, but the larger history of subproject 119 and the relationship between the CIA and the National Institute of Health (NIH) which contracted out some of the work has not been made public. On March 18, 2008, the Central Intelligence Agency released a document in response to a Freedom of Information Act request which discloses that CIA use of biomedical intellectual property developed at the Alfred Mann Foundation under direction of William Heetderks at the NIH, is "classified pursuant to an executive order" and is "intelligence sources and methods"[8]. William Heetderks is thought to have served as the interagency focal but again that is emergent.

Auditory prosthetics

Main articles: cochlear implant and auditory brainstem implant

Cochlear implants (CIs), auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs) are the three main categories for auditory prostheses. CI electrode arrays are implanted in the cochlea, ABI electrode arrays stimulate the cochlear nucleus complex in the lower brain stem, and AMIs stimulates auditory neurons in the inferior colliculus. Cochlear implants have been very successful among these three categories. Today Advanced Bionics and Medtronic are the major commercial providers of cochlea implants.

In contrast to traditional hearing aids that amplify sound and send it through the external ear, cochlear implants acquire and process the sound and convert it into electrical energy for subsequent delivery to the auditory nerve. The microphone of the CI system receives sound from the external environment and sends it to processor. The processor digitizes the sound and filters it into separate frequency bands that are sent to the appropriate tonotonic region in the cochlea that approximately corresponds to those frequencies.

In 1957, French researchers A. Djourno and C. Eyries, with the help of D. Kayser, provided the first detailed description of directly stimulation the auditory nerve in a human subject.[9] The individuals described hearing chirping sounds during simulation. In 1972, the first portable cochlear implant system in an adult was implanted at the House Ear Clinic. The U.S. Food and Drug Administration (FDA) formally approved the marketing of the House-3M cochlear implant in November 1984. [10]

Improved performance in cochlea implants not only depends on understanding the physical and biophysical limitations of implant stimulation but also on an understanding of the brain’s pattern processing requirements. Modern signal processing represents the most important speech information while also providing the brain the pattern recognition information that it needs. Pattern recognition in the brain is more effective than algorithmic preprocessing at identifying important features in speech. A combination of engineering, signal processing, biophysics, and cognitive neuroscience was necessary to produce the right balance of technology to maximize the performance of auditory prosthesis. [11]

Since the early 2000s FDA has been involved in a clinical trial of device termed the “Hybrid” by Cochlear Corporation. This trial is aimed at examining the usefulness of cochlea implantation in patients with residual low-frequency hearing. The “Hybrid” utilizes a shorter electrode than the standard cochlea implant, since the electrode is shorter it stimulates the basil region of the cochlea and hence the high-frequency tonotopic region. In theory these devices would benefit patients with significant low-frequency residual hearing who have lost perception in the speech frequency range and hence have decreased discrimination scores. [12]

Prosthetics for pain relief

Main article: Spinal Cord Stimulator

The SCS (Spinal Cord Stimulator) device has two main components: an electrode and a generator. The technical goal of SCS for neuropathic pain is to mask the area of a patient’s pain with a stimulation induced tingling, known as ”paresthesia”, because this overlap is necessary (but not sufficient) to achieve pain relief.[13] Paresthesia coverage depends upon which afferent nerves are stimulated. The most easily recruited by a dorsal midline electrode, close to the pial surface of spinal cord, are the large dorsal column afferents, which produce broad paresthesia covering segments caudally.

In ancient times the electrogeneic fish was used as a shocker to subside pain. Healers had developed specific and detailed techniques to exploit the generative qualities of the fish to treat various types of pain, including headache. Because of the awkwardness of using a living shock generator, a fair level skill was required to deliver the therapy to the target for the proper amount of time. (Including keeping the fish alive as long as possible) Electro analgesia was the first deliberate application of electricity. By the nineteenth century, most western physicians were offering their patients electrotherapy delivered by portable generator.[14] In the mid-1960s, however, three things converged to insure the future of electro stimulation.

1. Pacemaker technology, which had it start in 1950, became available.

2. Melzack and wall published their gate control theory of pain, which proposed that the transmission of pain could be blocked by stimulation of large afferent fibers. [15]

3. Pioneering physicians became interested in stimulating the nervous system to relieve patients from pain.

The design options for electrodes include their size, shape, arrangement, number, and assignment of contacts and how the electrode is implanted. The design option for the pulse generator include the power source, target anatomic placement location, current or voltage source, pulse rate, pulse width, and number of independent channels. Programming options are very numerous (a four-contact electrode offers 50 functional bipolar combinations). The current devices use computerized equipment to find the best options for use. This reprogramming option compensates for postural changes, electrode migration, changes in pain location, and suboptimal electrode placement. [16]

Today, Boston Scientific, Medtronic are the main providers of commercial SCS devices.

Motor prosthetics

Devices which support the function of autonomous nervous system include the implant for bladder control. In the somatic nervous system attempts to aid conscious control of movement include Functional electrical stimulation and the lumbar anterior root stimulator.

Bladder control implants

Main article: Sacral anterior root stimulator

Where a spinal cord lesion leads to paraplegia, patients have difficulty emptying their bladders and this can cause infection. From 1969 onwards Brindley developed the sacral anterior root stimulator, with successful human trials from the early 1980s onwards.[17] This device is implanted over the sacral anterior root ganglia of the spinal cord; controlled by an external transmitter, it delivers intermittent stimulation which improves bladder emptying. It also assists in defecation and enables male patients to have a sustained full erection.

The related procedure of sacral nerve stimulation is for the control of incontinence in able-bodied patients.[18]

Motor prosthetics for conscious control of movement

Main article: Brain-computer interface

Researchers are attempting to build motor neuroprosthetics that will help restore movement and the ability to communicate with the outside world to persons with motor disabilities such as tetraplagia or amyotrophic lateral sclerosis.

To capture electrical signals from the brain, scientists have developed microelectrode arrays smaller than a square centimeter that can be implanted in the skull to record electrical activity, transducing recorded information through a thin cable. After decades of research in monkeys, neuroscientists have been able to decode neuronal signals into movements. Completing the translation, researchers have built interfaces that allow patients to move computer cursors, and they are beginning to build robotic limbs and exoskeletons that patients can control by thinking about movement.

The technology behind motor neuroprostheses is still in its infancy. Investigators and study participants continue to experiment with different ways of using the prostheses. Having a patient think about clenching a fist, for example, produces a different result than having him or her think about tapping a finger. The filters used in the prostheses are also being fine-tuned, and in the future, doctors hope to create an implant capable of transmitting signals from inside the skull wirelessly, as opposed to through a cable.

Preliminary clinical trials suggest that the devices are safe and that they have the potential to be effective.[citation needed] Some patients have worn the devices for over two years with few, if any, ill effects.[citation needed]

Prior to these advancements, Philip Kennedy (Emory and Georgia Tech) had an operable if somewhat primitive system which allowed an individual with paralysis to spell words by modulating their brain activity. Kennedy's device used two neurotrophic electrodes: the first was implanted in an intact motor cortical region (e.g. finger representation area) and was used to move a cursor among a group of letters. The second was implanted in a different motor region and was used to indicate the selection.[19]

Developments continue in replacing lost arms with cybernetic replacements by using nerves normally connected to the pectoralis muscles. These arms allow a slightly limited range of motion, and reportedly are slated to feature sensors for detecting pressure and temperature.[20]

Dr. Todd Kuiken at Northwestern University and Rehabilitation Institute of Chicago has developed a method called targeted reinnervation for an amputee to control motorized prosthetic devices and to regain sensory feedback.

Sensory/motor prosthetics

In 2002 an array of 100 electrodes was implanted directly into the median nerve fibers of the scientist Kevin Warwick. The recorded signals were used to control a robot arm developed by Warwick's colleague, Peter Kyberd and was able to mimic the actions of Warwick's own arm.[21] Additionally, a form of sensory feedback was provided via the implant by passing small electrical currents into the nerve. This caused a contraction of the first lumbrical muscle of the hand and it was this movement that was perceived.[21]

Cognitive prosthetics

Sensory and motor prostheses deliver input to and output from the nervous system respectively. Theodore Berger at the University of Southern California defines a third class of prostheses[22] aimed at restoring cognitive function by replacing circuits within the brain damaged by stroke, trauma or disease. Work has begun on a proof-of-concept device - a hippocampal prosthesis which can mimic the function of a region of the hippocampus - a part of the brain responsible for the formation of memories.[23][24]

Commercial technology

Medtronic and Advanced Bionics are significant commercial names in the emergent market of Deep Brain Stimulation. Cyberkinetics is the first venture capital funded neural prosthetic company.

References

  1. ^ Laura Bailey. "HUniversity of Michigan News Service". Retrieved February 6 2006. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |dateformat= ignored (help)
  2. ^ Handa G (2006) "Neural Prosthesis – Past, Present and Future" Indian Journal of Physical Medicine & Rehabilitation 17(1)
  3. ^ A. Y. Chow, V. Y. Chow, K. Packo, J. Pollack,G. Peyman, and R. Schuchard, "The artificial silicon retina microchip for the treatment of vision loss from retinitis pigmentosa," Arch.Ophthalmol., vol. 122, p. 460, 2004
  4. ^ M. J. McMahon, A. Caspi, J. D.Dorn, K. H. McClure, M. Humayun, and R. Greenberg, "Spatial vision in blind subjects implanted with the second sight retinal prosthesis," presented at the ARVO Annu. Meeting, Ft. Lauderdale, FL, 2007.
  5. ^ G. S. Brindley and W. S. Lewin, "The sensations produced by electrical stimulation of the visual cortex," J. Physiol. (Lond.),vol. 196, p. 479, 1968
  6. ^ Weiland JD, Humayun MS. 2008. Visual prosthesis. Proceedings of the Ieee 96:1076-84
  7. ^ Weiland JD, Humayun MS. 2008. Visual prosthesis. Proceedings of the Ieee 96:1076-84
  8. ^ Central Intelligence Agency Freedom of Information Office, document control #F-2008-00760, released March 18, 2008 as a public inspection copy.
  9. ^ J. K. Niparko and B. W. Wilson, "History of cochlear implants," in Cochlear Implants:Principles and Practices. Philadelphia, PA: Lippincott Williams and Wilkins, 2000, pp. 103–108
  10. ^ W. F. House, Cochlear implants: My perspective
  11. ^ Fayad JN, Otto SR, Shannon RV, Brackmann DE. 2008. Cochlear and brainstern auditory prostheses "neural interface for hearing restoration: Cochlear and brain stem implants". Proceedings of the Ieee 96:1085-95
  12. ^ B. J. Gantz, C. Turner, and K. E. Gfeller, "Acoustic plus electric speech processing: Preliminary results of a multicenter clinical trial of the Iowa/Nucleus hybrid implant," Audiol. Neurotol., vol. 11 (suppl.), pp. 63–68, 2006, Vol 1
  13. ^ R. B. North, M. E. Ewend, M. A. Lawton, and S. Piantadosi, "Spinal cord stimulation for chronic, intractable pain: Superiority of 'multi-channel' devices," Pain, vol. 4, no. 2, pp. 119–130, 1991
  14. ^ D. Fishlock, "Doctor volts [electrotherapy]," Inst. Elect. Eng. Rev., vol. 47, pp. 23–28, May 2001
  15. ^ P. Melzack and P. D. Wall, "Pain mechanisms: A new theory," Science, vol. 150, no. 3699, pp. 971–978, Nov. 1965
  16. ^ North RB. 2008. Neural interface devices: Spinal cord stimulation technology. Proceedings of the Ieee 96:1108-19
  17. ^ Brindley GS, Polkey CE, Rushton DN (1982): Sacral anterior root stimulator for bladder control in paraplegia. Paraplegia 20: 365-381.
  18. ^ Schmidt RA, Jonas A, Oleson KA, Janknegt RA, Hassouna MM, Siegel SW, van Kerrebroeck PE. Sacral nerve stimulation for treatment of refractory urinary urge incontinence. Sacral nerve study group. J Urol 1999 Aug;16(2):352-357.
  19. ^ Gary Goettling. "Harnessing the Power of Thought". Retrieved April 22 2006. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |dateformat= ignored (help)
  20. ^ David Brown. "Washington Post". Retrieved September 14 2006. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |dateformat= ignored (help)
  21. ^ a b Warwick,K, Gasson,M, Hutt,B, Goodhew,I, Kyberd,P, Andrews,B, Teddy,P and Shad,A:“The Application of Implant Technology for Cybernetic Systems”, Archives of Neurology, 60(10), pp1369-1373, 2003
  22. ^ Berger T et al. (2005) "Restoring Lost Cognitive Function" IEEE Engineering in Medicine and Biology Magazine September/October pg 30-46
  23. ^ "World's first brain prosthesis revealed", by Duncan Graham-Rowe, New Scientist, 12 March, 2003
  24. ^ "Restoring Lost Cognitive Function--Hippocampal-Cortical Neural Prostheses", by Theodore Berger et al., IEEE Engineering in Medicine and Biology Magazine 24, 5, pp. 30-44, Sept.-Oct. 2005.

Further reading

Santhanam G, Ryu SI, Yu BM, Afshar A, Shenoy KV. 2006. A high-performance brain-computer interface. Nature 442:195-8

Patil PG, Turner DA. 2008. The development of brain-machine interface neuroprosthetic devices. Neurotherapeutics 5:137-46

Liu WT, Humayun MS, Liker MA. 2008. Implantable biomimetic microelectronics systems. Proceedings of the Ieee 96:1073-4

Harrison RR. 2008. The design of integrated circuits to observe brain activity. Proceedings of the Ieee 96:1203-16

Abbott A. 2006. Neuroprosthetics: In search of the sixth sense. Nature 442:125-7

Velliste M, Perel S, Spalding MC, Whitford AS, Schwartz AB (2008) "Cortical control of a prosthetic arm for self-feeding." Nature. 19;453(7198):1098-101.

Schwartz AB, Cui XT, Weber DJ, Moran DW “Brain-controlled interfaces: movement restoration with neural prosthetics.” (2006) Neuron 5;52(1):205-20

Santucci DM, Kralik JD, Lebedev MA, Nicolelis MA (2005) "Frontal and parietal cortical ensembles predict single-trial muscle activity during reaching movements in primates." Eur J Neurosci. 22(6): 1529-1540.

Lebedev MA, Carmena JM, O'Doherty JE, Zacksenhouse M, Henriquez CS, Principe JC, Nicolelis MA (2005) "Cortical ensemble adaptation to represent velocity of an artificial actuator controlled by a brain-machine interface." J Neurosci. 25: 4681-4893.

Nicolelis MA (2003) "Brain-machine interfaces to restore motor function and probe neural circuits." Nat Rev Neurosci. 4: 417-422.

Wessberg J, Stambaugh CR, Kralik JD, Beck PD, Laubach M, Chapin JK, Kim J, Biggs SJ, Srinivasan MA, Nicolelis MA. (2000) "Real-time prediction of hand trajectory by ensembles of cortical neurons in primates." Nature 16: 361-365.

See also

(for a list of universities see Neural Engineering - Neural Engineering Labs)

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