People who have suffered a stroke often forget how to carry out simple tasks, such as eating or walking. Those with neurodegenerative diseases like Alzheimers and dementia also lose skills. Neurotechnology is becoming an attractive tool for the cognitive rehabilitation of these patients — with brain-machine interfaces, neuronal activity can be monitored and directed to efficiently recover lost abilities. Nowadays, technology for reading and writing the mind has become a promising prospect even for cognitive improvement of healthy people. Will we be able to enhance abilities such as memory and attention by connecting machines to the brain?
Studies suggest we will. In the United States Air Force, neuroscientist Andy McKinley has performed trials with electrodes that zap the skull using a mild electrical current. Drone pilots learn to identify targets in radar images twice as fast when they train with this neurotechnology. Researcher Vince Clark, from the University of New Mexico in Albuquerque, found similar results: in his experiment, volunteers who received the electrical current progressed twice as fast in a game which required detecting hidden threats from a video.
Scientists think the effects of transcranial stimulation are not merely a placebo, as medical images show tangible changes in brain structure and function during and after these interventions. However, British neuroscientist Bryan Strange says “there is a debate over what exactly the stimulation does to the brain”.
Researchers know that electrical current increases neuronal plasticity, which encourages the formation of cell connexions that reinforce learning. However, the science has a long way to go. A key problem of electrical transcranial stimulation is that the slight current applied over the scalp (up to two milliamperes, normally), diffuses through the bone and only exerts a faint physical influence on the underlying neurons. There is an alternative, magnetic transcranial stimulation, which avoids this problem because it generates a magnetic field directly beneath the bony surface.
Magnetic stimulation has proved promising both in cognitive rehabilitation of mentally ill patients and cognitive enhancement of healthy users, but it requires bulky laboratory equipment which is not consumer-friendly. Researchers who use these stimulation techniques, both electrical and magnetic, face two common challenges: first, they must demonstrate that the cognitive improvement carries through in day to day activities unrelated to the training task, and secondly, they must prove that the enhancement doesn’t wear off in the long term (days or weeks).
Modulating and monitoring neurons
At the Laboratory for Clinical Neuroscience in the Polytechnic University of Madrid, Bryan Strange’s team studies the cognitive effects of deep brain stimulation. This technique uses electrodes, surgically implanted beneath the skull, to deliver a current which “acts directly on clusters of cells which are relevant for cognitive performance”, according to the neuroscientist. Deep brain stimulation helps with tremors, psychiatric disorders and some symptoms of Alzheimers’ disease and dementia, but it’s an extremely invasive technique which will not appeal to healthy users looking to sharpen their mind.
In the world of neurotechnology, electroencephalography (EEG) dominates the consumer market: it’s a noninvasive technique which registers neuronal activity using sensors on the head’s surface. Years ago, this required electrodes and gels rubbed over the scalp, but modern brain-computer interfaces are like headbands. The sensors are commonly used to control machines, anything from video games to robotic arms, but they have also found a place in cognitive enhancement and rehabilitation.
Unlike electrical and magnetic stimulation, EEG technology doesn’t aim to modulate the brain cells’ activity, it merely interprets their behavior. The neurotechnology company Bitbrain, for instance, has developed this technique to monitor a very specific type of neuronal activity which scientists have correlated with faster mental processing, improved working memory and sustained attention.
Their cognitive enhancement program requires users to progress in a simple mind-controlled computer game — using their thoughts, users must change the colour of a square which appears on-screen. The computer only allows the color change to happen when the EEG headband detects that the users’ mind has entered the cognitive state which must be trained. In this way, the player learns to direct his or her own mind towards that state of enhanced memory and attention, reinforcing the relevant neural pathways.
“The main difficulty is personalizing this procedure for each user”, says Javier Mínguez, the company’s chief scientific officer. The neuronal activity which this training regime aims to enhance produces a particular EEG signal, but it is not identical in everyone’s brains. Even the same person can generate a slightly different brainwave pattern depending on their mood, so the sensors must be calibrated before each session.
An ethical dilemma
The emergence of this branch of neurotechnology, halfway between clinical research and commercial interest, is problematic, according to Bryan Strange. “I want to highlight that doctors like me are more focused on using these techniques on patients with problems,” he says. According to Strange, improving the abilities of healthy people poses an ethical dilemma. However, bioethicist Allen Buchanan, who is a professor of Philosophy at Duke University, argues in his book “Better Than Human” that the desire to improve, which includes cognitive improvement, is a part of human nature.
In an interview with The Atlantic, Buchanan pointed out that expensive or exclusive techniques can heighten social differences, while technology that extends rapidly throughout society can even out inequality — like mobile phones. “Cognitive enhancements like transcranial direct current stimulation and cognition-enhancing drugs may become inexpensive fairly quickly, and in turn might diffuse much more rapidly than literacy did”, he argues.
The company Bitbrain has developed programs for patient rehabilitation as well as cognitive enhancement of healthy users — for instance, elite athletes. The results are more remarkable in patients who have suffered significant cognitive loss, since they have greater room for improvement. Javier Mínguez recalls that his first experiment was disappointing because he tried to sharpen the mental prowess of volunteers from an engineering faculty. These participants already had outstanding cognitive performance and only registered modest improvements. A more recent trial has demonstrated the potential of this sort of training to restore mental function in patients who suffer major depression.
As is the case with transcranial stimulation, it is difficult to prove that the effects of a particular training regime will also apply in cognitive activities of the day to day. According to the scientist, qualitative change at least is noticeable: patients with depression started reading novels again, or began to follow the news on television. Do these effects last in the long term? Only if the user continues to exercise those mental faculties, Mínguez says: exactly the same as would happen following strength training at the gym.