Another company, Neural Signals, in Atlanta, Georgia, has developed a glass electrode to read signals from the brain, rather than a bed of needles. The tiny, hollow glass cone is the size of a ballpoint pen tip and is filled with wires and a neural growth factor that encourages neurons to send extensions into the electrode. While the electrode reads information from a much smaller sample of neurons than the BrainGate chip, it still records signals from brain cells, relays those signals to an amplifier and transmitter and then to a computer.

Researchers hope this intracranial technology -- that is, devices implanted in the brain -- will bring many new applications to the disabled. They envision patients controlling a virtual keyboard with a specially-designed interface that they can use to access a word processor, the Internet, or switches for lights and the TV. Both Neural Signals and Cyberkinetics have started testing their devices in disabled volunteers, who are now able to perform tasks like checking email and controlling a robotic arm. This is just a first step toward what patients may ultimately be able to do using intracranial devices.

A BCI volunteer uses EEG signals recorded from the scalp over sensorimotor cortex to move a cursor from the center of the screen to a target on the periphery. CREDIT: "Michael Wren, Wadsworth Center, N. Y. State Dept. of Health

While intracranial devices garner much attention, there have also been impressive results from extracranial devices — that is, those outside the head. Jonathan Walpow at the Wadsworth Center in New York has demonstrated that electrodes on the scalp can read signals that can be translated into movements. Patients have been able to communicate by spelling out words on a computer and controlling a robotic arm in multi-dimensions with comparable success to intracranial BCIs in monkeys. However, unlike the intracranial devices where different chips or electrodes implanted in distinct areas of the brain could control different actions and allow the user to perform several tasks at once, extracranial devices take readings from the entire scalp. Would scalp readings be able to distinguish specific signals from different areas of the brain to execute different actions simultaneously? "Yes, it is conceivable," according to Wolpaw, "and, in fact, we have demonstrated it. Each electrode tends to be most affected by the brain areas immediately below it. Thus, electrodes at different locations on the scalp are most affected by different areas of the brain."

Since the extracranial devices take readings from the entire brain rather than just a specific part of the brain, it appears to require more concentration to execute a task. Researchers familiar with both intracranial and extracranial approaches suggest that the scalp recordings may be more limited than their intracranial counterparts. Some feel that the extracranial devices demand too much attention from the user to be at all useful. However, Wolpaw claims that their studies have shown that "trained users can use the BCI to answer questions that are spoken to them or can do mental arithmetic while controlling the cursor."

Is it worth it?

With any new technology, there are worries about the ethical issues that arise with it. Of course, restoring mobility to disabled patients is a positive application. However, there are concerns as to how quickly this technology is advancing to human trials. Both intracranial devices require several hours of surgery and the current level of usefulness of these devices has been questioned.

Some researchers question whether the human trials are currently premature and argue for more animal studies. However, proponents point out that the human trials have allowed researchers the added benefit of studying the neural circuitry of cognition, which is very difficult to study in animals. While the progress in BCI research has benefited from the recent push in studies, at some point the risk-to-benefit ratio and ethical implications of human trials has to be assessed. Andrew Schwartz, a professor of neurobiology at the University of Pittsburgh, studies the brain-computer interface and feels that the jump of intracranial devices to human trials is happening very rapidly. "I guess you have to actually look at the patient they implanted in and assess if there's an increase in quality of life," says Schwartz.

There are also concerns about other related research and technologies that could develop from BCI work such as memory enhancement chips, mind readers, or devices to control fighter planes with minds. Researchers attest that we are a long way from those scenarios. However, early discussions about the ethical concerns regarding these technologies and the rational and responsible approaches to such research have already begun.

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