Seite - 66 - in Cyborg Mind - What Brain–Computer and Mind–Cyberspace Interfaces Mean for Cyberneuroethics

66 • Cyborg Mind the same time, there is some evidence that TMS could be used for cognitive enhancement for healthy individuals, including improving cognitive skills, moods and social cognition.71 However, one of the challenges with TMS is that the stimulation effects are generally only temporary. Difficulties also exist with directing the mag- netic pulses to a specific area in the brain that is responsible for a certain function without activating other areas as well.72 Transcranial Direct Current Stimulation (TDCS) and Transcranial Alternating Current Stimulation (TACS) The noninvasive stimulation of the brain through the use of electrical cur- rents is not new. Ever since the beginning of the twentieth century, it has been possible to apply electrodes to the scalp of a person, enabling an electric current to be created in the brain.73 With TDCS, a weak electric field is applied to the scalp (using nonin- vasive electrodes) in the region of interest, thereby inducing intracerebral current flow leading to alteration of brain function. In a research setting, measurements can then be obtained through the study of small reaction time changes in behavioural performance on psychological tasks.74 Recent studies in stroke rehabilitation strategies have shown that TDCS may improve a patient’s ability to learn a simple coordination exercise, with improvement remaining three months after the end of the experiment. Studies are also taking place with the aim of treating depression and the effects of Parkinson’s disease.75 In addition, it has been suggested that the procedure could be used to enhance the cognitive ability of healthy people by improving working memory, word association and complex problem-solving.76 For example, in 2016, the U.S. military reported that TDCS could improve skill learning and performances, such as multitasking of air crew and other military per- sonnel.77 Other studies have suggested that several sessions of TDCS applied to the prefrontal cortex improved the moods of some individuals for several weeks78 or made people less likely to take risks.79 In this regard, although devices prescribed for medical treatments must meet specific safety standards, there is currently no legislation in Europe or the United States regulating the use of TDCS for persons who simply hope to enhance certain aspects of their cognition. TDCS headsets can even be purchased online, enabling them to be used (even on children) without taking into account the eventual risks.80 With TACS, the procedure is similar to TDCS, but alternating current is used instead of a direct current. This causes the underlying neurons of the brain to oscillate at specific frequencies. This open access edition has been made available under a CC-BY-NC-ND 4.0 license thanks to the support of Knowledge Unlatched. Not for resale.