Conceptualizing a cyborg

Jan 18, 2007
Conceptualizing a cyborg
Schematic of stretch-grown axons, showing axons growing on electrodes on right and computer-controlled motor pulling axons to left. Blow-up is close-up of stretch-grown axons. Credit: Douglas H. Smith, MD, University of Pennsylvania School of Medicine

Investigators at the University of Pennsylvania School of Medicine describe the basis for developing a biological interface that could link a patient's nervous system to a thought-driven artificial limb. Their conceptual framework - which brings together years of spinal-cord injury research - is published in the January issue of Neurosurgery.

"We're at a junction now of developing a new approach for a brain-machine interface," says senior author Douglas H. Smith, MD, Professor of Neurosurgery and Director of the Center for Brain Injury and Repair at Penn. "The nervous system will certainly rebel if you place hard or sharp electrodes into it to record signals. However, the nervous system can be tricked to accept an interface letting it do what it likes - assimilating new nerve cells into its own network".

To develop the next generation of prosthetics the idea is to use regions of undamaged nervous tissue to provide command signals to drive a device, such as an artificial limb. The challenge is for a prosthesis to perform naturally, relaying two-way communication with the patient's brain. For example, the patient's thoughts could convert nerve signals into movements of a prosthetic, while sensory stimuli, such as temperature or pressure provides feedback to adapt the movements.

The central feature of the proposed interface is the ability to create transplantable living nervous tissue already coupled to electrodes. Like an extension cord, of sorts, the non-electrode end of the lab-grown nervous tissue could integrate with a patient's nerve, relaying the signals to and from the electrode side, in turn connected to an electronic device.

This system may one day be able to return function to people who have been paralyzed by a spinal-cord injury, lost a limb, or in other ways. "Whether it is a prosthetic device or a disabled body function, the mind could regain control," says Smith.

To create the interface, the team used a newly developed process of stretch growth of nerve fibers called axons, previously pioneered in Smith's lab. Two adjacent plates of neurons are grown in a bioreactor. Axons sprout out to connect the neuron populations on each plate. The plates are then slowly pulled apart over a series of days, aided by a precise computer-controlled motor system, until they reached a desired length.

For the interface, one of the plates is an electrical microchip. Because Smith and his team have shown that stretch-grown axons can transmit active electrical signals, they propose that the nervous-tissue interface - through the microchip - could detect and record real-time signals conducted down the nerve and stimulate the sensory signals back through the axons.

In another study, Smith and colleagues showed that these stretch-grown axons could grow when transplanted into a rat model of spinal-cord damage. The team is now is the midst of studies measuring neuronal electrical activity across newly engineered nerve bridges and the restoration of motor activity in experimental animals.

Source: University of Pennsylvania

Explore further: Recombinant peptide for transplantation of pancreatic islets in mice models of diabetes

Related Stories

Researcher discusses electronic cochlear architecture

Jan 20, 2015

Researchers have developed an architecture and digital implementation of an electronic cochlea with an acoustic fovea and address event representation using field programmable gate arrays. Prof. Andreas Andreou of Johns Hopkins ...

When emotions control objects

Oct 20, 2014

Dimming a light, immersive playing on a computer, and tracking yoga exercises in real time – sensors developed by SmartCardia use various vital signs to transmit data to a host of everyday objects.

Smartphones as a health tool for older adults

Aug 01, 2014

A team of researchers from the Universitat Politècnica de Catalunya · BarcelonaTech (UPC) and the Universitat Autònoma de Barcelona (UAB) is creating a smartphone app that will help older adults to understand ...

Emotion detectors could make driving safer

Mar 14, 2014

Irritation, in particular, can make drivers more aggressive and less attentive. EPFL researchers, in collaboration with PSA Peugeot Citroen, have developed an on-board emotion detector based on the analysis ...

Recommended for you

Novel nanoparticle therapy promotes wound healing

Mar 26, 2015

An experimental therapy developed by researchers at Albert Einstein College of Medicine of Yeshiva University cut in half the time it takes to heal wounds compared to no treatment at all. Details of the therapy, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.