One small sip for “S3” was one miraculous leap for neurotechnology. According to a recent report in Nature, a 58-year-old woman with long-standing tetraplegia (named “S3” in the report) mobilized a free-standing robotic arm to reach out and grasp a cup of coffee—a highly complex fine-motor movement—with merely her thoughts.1
Five years before this awe-inspiring moment, a tiny neural implant (called BrainGate) with 96 electrodes was implanted in S3’s motor cortex. BrainGate’s sensor recorded the electrical activity of an array of motor neurons triggered when S3 imagined specific reach and grasp movements; these patterns of motor signals were “translated” (digitalized) into a series of zeros and ones that instructed a computer to operate an independent robotic (mechanical) arm with 3-dimensional movements. With a neural-computer interface, S3 could grasp a cup of cof-fee with brain signals alone. Remarkably, the motor cortex’s firing pattern—the sequence of zeros and ones—that had been recorded 5 years earlier remained essentially unchanged. S3 had a brain-computer interface to thank for restoring volitional movements to her paralyzed limb. Such an achievement is just one of many notable stories unfolding in the emerging field of neurotechnology.
Neurotechnology refers to the science of applying our emerging understanding of the brain, consciousness, thought, and higher-order activities of the mind into developing technologies. The tools of neurotechnology, however, are not new for psychiatrists. For example, in the realm of diagnostic imaging, functional MRI (fMRI) scanning discoveries have linked the brain’s anatomy with localized emotional and cognitive functions and dysfunctions.
One groundbreaking finding was Area 25 that Helen S. Mayberg, MD, identified as a “nerve center” for depression; it may be a reliable barometer for antidepressant treatment as well.2 Moreover, modern electro- and magneto-encephalography can detect tumors, find stroke sites, and specify epilepsy-prone brain areas. Other advances in neuroimaging promise to identify dysfunctional neural circuits associated with human psychopathology and suffering.
Beyond diagnostics, neurotechnologies are used in psychiatric treatment. The electromagnetic “wand” used in repetitive transcranial magnetic stimulation (rTMS) is FDA-approved for the treatment of depression, and emerging research indicates that rTMS could help less-en the intrusive thoughts of obsessive-compulsive disorder, improve the painful apathy associated with certain psychotic disorders, and diminish chronic pain caused by migraine headaches and phantom limb syndrome.
Neural implants, including computer chips and optic probes, are already in use to treat epilepsy and Parkinson disease. Similarly, research is under way to use deep brain stimulators to treat obsessive-compulsive disorder, refractory depression, Tourette syndrome, and addictions and to curb appetite and reduce obesity. Advanced drug delivery systems are being designed to zero in on diseased brain sites or turn on genes that could promote cell growth—and to do so without the degree of collateral damage associated with less precise methods.
Smart drugs, “nootropics,” that selectively boost the functioning of neural circuits involved in memory and cognition are another budding frontier. Perhaps the most incredible application is the field of optogenetics, where specially engineered, light-activated (or light-inactivated) ion channels are implanted in the brain to curtain the firing of neurons associated with anxiety or trauma. Native to unicellular algae found in a pond, these implantable ion channels—such as blue-light–activated channelrhodopsin that promotes neuronal firing or yellow-light–activated halorhodopsin that actually silences a neuron—can now assist neuroscientists in disentangling complicated neural circuits and, perhaps, in identifying an anxiety gene that could be targeted with gene therapy. This work is under way with mice, a few cortical steps away from man.3
1. Hochberg LR, Bacher D, Jarosiewicz B, et al. Reach and grasp by people with tetraplegia using a neurally controlled robotic arm. Nature. 2012;485:372-375.
2. Mayberg HS, Lozano AM, Voon V, et al. Deep brain stimulation for treatment-resistant depression. Neuron. 2005;45:651-660.
3. Schoonover CE, Rabinowitz A. Control desk for the neural switchboard. New York Times. May 16, 2011. http://www.nytimes.com/2011/05/17/science/17optics.html?pagewanted=all&_r=0. Accessed October 4, 2012.