Humans have intervened directly in the brain for a long time. Archaeological evidence shows that people in the late Stone Age in Europe, pre-Incan civilizations, the Ancient Egyptians, the Romans and Byzantines all performed brain surgery for medical, spiritual and magical purposes. During the last century, brain intervention experienced a steep rise and fall: electroconvulsive therapy (ECT), ‘split-brain’ surgery and lobotomy were each first heralded as wonder cures for depression, epilepsy, schizophrenia and many other illnesses in the first half of the 20th century. But each was to some extent discredited as they came to be seen as treatments that were often inappropriate and sometimes harmful, leading to the view that their uncritical and widespread use arose from the hubris of a medical profession bound by too few rules.
Far more targeted applications of these treatments, and other treatments that intervene directly into the human brain, are only slowly being re-introduced to medical practice, with very strict risk/ benefit assessments and strong consent and oversight procedures in place.
Intervening in the brain has always raised hope and fear in equal measure: hope of curing crippling neurological conditions or improving human capabilities beyond normal limits against fear of harmful manipulation with unforeseen consequences or the wilful destruction of what it means to be human. Currently, technologies are emerging that intervene in the brain which seem to promise significant benefits to people with neurological conditions. Such neurotechnologies could also potentially be used in non-medical settings. For example, Brain Computer Interfaces (BCIs) which connect the brain to a computer system could help people who have a locked-in syndrome to communicate or even interact with the outside world by using thoughts to direct a bed, wheelchair or speech computer. BCIs can be used in non-medical ways, for computer gaming, where games are ‘thought-controlled’ – and there is growing interest in using BCIs in the military, to enable military personnel who have lost limbs to control their prosthetic devices directly from their brain, or to improve soldiers’ capabilities or employ though-controlled, remote weaponry.
Neurostimulation such as Deep-Brain Stimulation (DBS), where electrodes are implanted into the brain, has been used to treat illnesses such Parkinson’s and severe depression. Transcranial Direct Current Stimulation (tDCS), where areas of the brain are stimulated directly with low electrical current, is being used to treat some psychiatric disorders, to aid rehabilitation and in some cases in the hope of enhancing cognitive performance.