View source for Neurotechnology

{{short description|Technology that interfaces with the nervous system to monitor or modify neural function}}
'''Neurotechnology''' encompasses any method or [[electronics|electronic]] device which interfaces with the [[nervous system]] to monitor or modulate neural activity.<ref name=":12">{{cite journal | vauthors = Goering S, Klein E, Sullivan LS, Wexler A, y Arcas BA, Bi G, Carmena JM, Fins JJ, Friesen P, Gallant J, Huggins JE, Kellmeyer P, Marblestone A, Mitchell C, Parens E, Pham M, Rubel A, Sadato N, Teicher M, Wasserman D, Whittaker M, Wolpaw J, Yuste R | display-authors = 6 | title = Recommendations for Responsible Development and Application of Neurotechnologies | journal = Neuroethics | pages = 365–386 | date = April 2021 | volume = 14 | issue = 3 | pmid = 33942016 | pmc = 8081770 | doi = 10.1007/s12152-021-09468-6 }}</ref><ref name="pmid29326561">{{cite journal | vauthors = Müller O, Rotter S | title = Neurotechnology: Current Developments and Ethical Issues | journal = Frontiers in Systems Neuroscience | volume = 11 | issue =  | pages = 93 | year = 2017 | pmid = 29326561 | pmc = 5733340 | doi = 10.3389/fnsys.2017.00093 | doi-access = free }}</ref>

Common design goals for neurotechnologies include using neural activity readings to control external devices such as [[neuroprosthetics]], altering neural activity via [[Neuromodulation (medicine)|neuromodulation]] to repair or normalize function affected by [[neurological disorder]]s,<ref>{{cite journal | vauthors = Cook MJ, O'Brien TJ, Berkovic SF, Murphy M, Morokoff A, Fabinyi G, D'Souza W, Yerra R, Archer J, Litewka L, Hosking S, Lightfoot P, Ruedebusch V, Sheffield WD, Snyder D, Leyde K, Himes D | display-authors = 6 | title = Prediction of seizure likelihood with a long-term, implanted seizure advisory system in patients with drug-resistant epilepsy: a first-in-man study | journal = The Lancet. Neurology | volume = 12 | issue = 6 | pages = 563–71 | date = June 2013 | pmid = 23642342 | doi = 10.1016/s1474-4422(13)70075-9 | s2cid = 33908839 }}</ref> or [[Neuroenhancement|augmenting cognitive abilities]].<ref name=":022">{{cite journal | vauthors = Cinel C, Valeriani D, Poli R | title = Neurotechnologies for Human Cognitive Augmentation: Current State of the Art and Future Prospects | journal = Frontiers in Human Neuroscience | volume = 13 | pages = 13 | date = 31 January 2019 | pmid = 30766483 | pmc = 6365771 | doi = 10.3389/fnhum.2019.00013 | doi-access = free }}</ref> In addition to their therapeutic or commercial uses, neurotechnologies also constitute powerful research tools to advance fundamental [[neuroscience]] knowledge.<ref>{{cite journal | vauthors = Wander JD, Rao RP | title = Brain-computer interfaces: a powerful tool for scientific inquiry | journal = Current Opinion in Neurobiology | volume = 25 | pages = 70–5 | date = April 2014 | pmid = 24709603 | pmc = 3980496 | doi = 10.1016/j.conb.2013.11.013 }}</ref><ref>{{cite journal | vauthors = Golub MD, Chase SM, Batista AP, Yu BM | title = Brain-computer interfaces for dissecting cognitive processes underlying sensorimotor control | journal = Current Opinion in Neurobiology | volume = 37 | pages = 53–58 | date = April 2016 | pmid = 26796293 | pmc = 4860084 | doi = 10.1016/j.conb.2015.12.005 }}</ref><ref>{{cite journal | vauthors = Kim CK, Adhikari A, Deisseroth K | title = Integration of optogenetics with complementary methodologies in systems neuroscience | journal = Nature Reviews. Neuroscience | volume = 18 | issue = 4 | pages = 222–235 | date = March 2017 | pmid = 28303019 | pmc = 5708544 | doi = 10.1038/nrn.2017.15 }}</ref><ref>{{cite journal | vauthors = Rawji V, Latorre A, Sharma N, Rothwell JC, Rocchi L | title = On the Use of TMS to Investigate the Pathophysiology of Neurodegenerative Diseases | journal = Frontiers in Neurology | volume = 11 | pages = 584664 | date = 2020-11-03 | pmid = 33224098 | pmc = 7669623 | doi = 10.3389/fneur.2020.584664 | doi-access = free }}</ref>

Some examples of neurotechnologies include [[deep brain stimulation]], photostimulation based on [[optogenetics]] and [[photopharmacology]], [[transcranial magnetic stimulation]], [[transcranial electric stimulation]] and [[brain–computer interface]]s, such as [[cochlear implant]]s and [[retinal implant]]s.

==Background==
{{Essay-like|section|date=October 2021}}
The field of neurotechnology has been around for nearly half a century but has only reached maturity in the last twenty years. The advent of [[brain imaging]] revolutionized the field, allowing researchers to directly monitor the brain's activities during experiments. Practice in neurotechnology can be found in fields such as pharmaceutical practices, be it from drugs for depression, sleep, [[ADHD predominantly inattentive|ADHD]], or anti-neurotics to cancer scanning, [[stroke rehabilitation]], etc.

Many in the field aim to control and harness more of what the brain does and how it influences lifestyles and personalities. Commonplace technologies already attempt to do this; games like [[Brain Age: Train Your Brain in Minutes a Day!|BrainAge]],<ref>Nintendo Company of America. BrainAge (2006). Based on the work of [[Ryuta Kawashima]], M.D.</ref> and programs like [[Fast ForWord]]<ref name="Merzenich1999">{{cite book| vauthors = Broman SH, Fletcher J |title=The changing nervous system: neurobehavioral consequences of early brain disorders|url=https://books.google.com/books?id=paxE8PFrsLEC|year=1999|publisher=Oxford University Press US|isbn=978-0-19-512193-3}}</ref> that aim to improve brain function, are neurotechnologies.

Currently, modern science can image nearly all aspects of the brain as well as control a degree of the function of the brain. It can help control [[Depression (mood)|depression]], over-activation, sleep deprivation, and many other conditions. Therapeutically it can help improve [[stroke]] patients' motor coordination, improve brain function, reduce epileptic episodes (see [[epilepsy]]), improve patients with degenerative motor diseases ([[Parkinson's disease]], [[Huntington's disease]], [[ALS]]), and can even help alleviate [[phantom pain]] perception.<ref>{{cite book | vauthors = Doidge N |title=The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science |publisher=Viking Adult |year=2007 |isbn=978-0-670-03830-5}}</ref> Advances in the field promise many new enhancements and rehabilitation methods for patients with neurological problems. The neurotechnology revolution has given rise to the [[Decade of the Mind]] initiative, which was started in 2007.<ref name="pmid22135580">{{cite journal | vauthors = Olds JL | title = For an international decade of the mind | journal = The Malaysian Journal of Medical Sciences | volume = 18 | issue = 2 | pages = 1–2 | date = April 2011 | pmid = 22135580 | pmc = 3216206 | doi =  }}</ref> It also offers the possibility of revealing the mechanisms by which [[mind]] and [[consciousness]] emerge from the brain.

==Types==

===Deep brain stimulation===
{{Main|Deep brain stimulation}}
Deep brain stimulation is currently used in patients with movement disorders to improve the quality of life in patients.<ref name="Gross2008"/>

===Transcranial ultrasound stimulation===
Transcrancial ultrasound stimulation (TUS) is a technique using ultrasound to modulate neural activity in the brain. It is an emerging technique that has shown therapeutic promise in a variety of neurological diseases. <ref>{{Cite web|title=TUS|url=https://www.biomedcentral.com/collections/transcranial-ultrasound-stimulation|website=BiomedCentral|language=en}}</ref>

===Transcranial magnetic stimulation===
{{Main|Transcranial magnetic stimulation|Pulsed electromagnetic field therapy}}

Transcranial magnetic stimulation (TMS) is a technique for applying magnetic fields to the brain to manipulate electrical activity at specific loci in the brain.<ref>{{cite journal | vauthors = Wassermann EM | title = Risk and safety of repetitive transcranial magnetic stimulation: report and suggested guidelines from the International Workshop on the Safety of Repetitive Transcranial Magnetic Stimulation, June 5-7, 1996 | journal = Electroencephalography and Clinical Neurophysiology | volume = 108 | issue = 1 | pages = 1–16 | date = January 1998 | pmid = 9474057 | doi = 10.1016/S0168-5597(97)00096-8 | url = https://zenodo.org/record/1259909 }}</ref> This field of study is currently receiving a large amount of attention due to the potential benefits that could come out of better understanding this technology.<ref name="Illes2006">{{cite journal | vauthors = Illes J, Gallo M, Kirschen MP | title = An ethics perspective on transcranial magnetic stimulation (TMS) and human neuromodulation | journal = Behavioural Neurology | volume = 17 | issue = 3–4 | pages = 149–57 | year = 2006 | pmid = 17148834 | pmc = 5471539 | doi = 10.1155/2006/791072 | doi-access = free }}</ref> Transcranial magnetic movement of particles in the brain shows promise for drug targeting and delivery as studies have demonstrated this to be noninvasive on brain physiology.<ref name=":0">{{cite journal | vauthors = Ramaswamy B, Kulkarni SD, Villar PS, Smith RS, Eberly C, Araneda RC, Depireux DA, Shapiro B | display-authors = 6 | title = Movement of magnetic nanoparticles in brain tissue: mechanisms and impact on normal neuronal function | journal = Nanomedicine | volume = 11 | issue = 7 | pages = 1821–9 | date = October 2015 | pmid = 26115639 | pmc = 4586396 | doi = 10.1016/j.nano.2015.06.003 }}</ref>

Transcranial magnetic stimulation is a relatively new method of studying how the brain functions and is used in many research labs focused on behavioral disorders, [[epilepsy]], [[PTSD]], [[migraine]], hallucinations, and other disorders.<ref name="Illes2006" /> Currently, repetitive transcranial magnetic stimulation is being researched to see if positive behavioral effects of TMS can be made more permanent. Some techniques combine TMS and another scanning method such as EEG to get additional information about brain activity such as cortical response.<ref name="Veniero2009">{{cite journal | vauthors = Veniero D, Bortoletto M, Miniussi C | title = TMS-EEG co-registration: on TMS-induced artifact | journal = Clinical Neurophysiology | volume = 120 | issue = 7 | pages = 1392–9 | date = July 2009 | pmid = 19535291 | doi = 10.1016/j.clinph.2009.04.023 | hdl-access = free | s2cid = 4496573 | hdl = 11572/145615 }}</ref>

===Transcranial direct current stimulation===
{{Main|Transcranial direct current stimulation}}

Transcranial direct current stimulation (TDCS) is a form of [[neurostimulation]] which uses constant, low current delivered via electrodes placed on the scalp. The mechanisms underlying TDCS effects are still incompletely understood, but recent advances in neurotechnology allowing for ''in vivo'' assessment of brain electric activity during TDCS<ref>{{cite journal | vauthors = Soekadar SR, Witkowski M, Cossio EG, Birbaumer N, Robinson SE, Cohen LG | title = In vivo assessment of human brain oscillations during application of transcranial electric currents | journal = Nature Communications | volume = 4 | pages = 2032 | year = 2013 | pmid = 23787780 | pmc = 4892116 | doi = 10.1038/ncomms3032 | bibcode = 2013NatCo...4.2032S }}</ref> promise to advance understanding of these mechanisms. Research into using TDCS on healthy adults have demonstrated that TDCS can increase cognitive performance on a variety of tasks, depending on the area of the brain being stimulated. TDCS has been used to enhance language and mathematical ability (though one form of TDCS was also found to inhibit math learning),<ref name=PMID_25970697>{{cite journal | vauthors = Grabner RH, Rütsche B, Ruff CC, Hauser TU | title = Transcranial direct current stimulation of the posterior parietal cortex modulates arithmetic learning | journal = The European Journal of Neuroscience | volume = 42 | issue = 1 | pages = 1667–74 | date = July 2015 | pmid = 25970697 | doi = 10.1111/ejn.12947 | url = https://www.zora.uzh.ch/id/eprint/113360/1/Grabner_EJN_2015.pdf | quote = Cathodal tDCS (compared with sham) decreased learning rates during training and resulted in poorer performance which lasted over 24 h after stimulation. Anodal tDCS showed an operation-specific improvement for subtraction learning. | s2cid = 37724278 }}</ref> attention span, problem solving, memory,<ref name=PMID_26457823>{{cite journal | vauthors = Gray SJ, Brookshire G, Casasanto D, Gallo DA | title = Electrically stimulating prefrontal cortex at retrieval improves recollection accuracy | journal = Cortex; A Journal Devoted to the Study of the Nervous System and Behavior | volume = 73 | pages = 188–94 | date = December 2015 | pmid = 26457823 | doi = 10.1016/j.cortex.2015.09.003 | quote = We found that stimulation of dlPFC significantly increased recollection accuracy, relative to a no-stimulation sham condition and also relative to active stimulation of a comparison region in left parietal cortex. | s2cid = 19886903 }}</ref> coordination and relieve depression <ref>{{cite journal | vauthors = Nitsche MA, Boggio PS, Fregni F, Pascual-Leone A | title = Treatment of depression with transcranial direct current stimulation (tDCS): a review | journal = Exp Neurol | year = 2009 | volume = 219 | issue = 1 | pages = 14–19 | pmid = 19348793| doi = 10.1016/j.expneurol.2009.03.038 | s2cid = 695276 }}</ref><ref>{{cite journal | vauthors = Brunoni AR, Moffa AH, Fregni F, Palm U, Padberg F, Blumberger DM, Daskalakis ZJ, Bennabi D, Haffen E, Alonzo A, Loo CK | title = Transcranial direct current stimulation for acute major depressive episodes: meta-analysis of individual patient data | journal = Br J Psychiatry | year = 2016 | volume = 208 | issue = 6 | pages = 522–531 | pmid = 27056623 | doi = 10.1192/bjp.bp.115.164715 | pmc = 4887722 }}</ref><ref>{{cite journal | vauthors = Tecchio F, Bertoli M, Gianni E, L'Abbate T, Sbragia E, Stara S, Inglese M| title = Parietal dysfunctional connectivity in depression in multiple sclerosis | journal = Mult Scler | year = 2020 | volume = 27 | issue = 9 | pages = 1468–1469 | pmid = 33084529 | doi = 10.1177/1352458520964412 | s2cid = 224829189 }}</ref> and chronic fatigue.<ref>{{cite journal | vauthors = Gianni E, Bertoli M, Simonelli I, Paulon L, Tecchio F, Pasqualetti P | title = tDCS randomized controlled trials in no-structural diseases: a quantitative review | journal = Scientific Reports | year = 2021 | volume = 11 | issue = 1 | page = 16311 | pmid = 34381076| doi = 10.1038/s41598-021-95084-6 | pmc = 8357949 | bibcode = 2021NatSR..1116311G | hdl = 11573/1575485 | hdl-access = free }}</ref><ref>{{cite journal | vauthors = Tecchio F, Cancelli A, Pizzichino A, L'Abbate T, Gianni E, Bertoli M, Paulon L, Zannino S, Giordani A, Lupoi D, Pasqualetti P, Mirabella M, Filippi MM| title = Home treatment against fatigue in multiple sclerosis by a personalized, bilateral whole-body somatosensory cortex stimulation | journal = Mult Scler Relat Disord | year = 2022 | volume = 63 | page = 103813 | pmid = 35597081 | doi = 10.1016/j.msard.2022.103813 | s2cid = 248967047 }}</ref>

===Electrophysiology===
[[Electroencephalography]] (EEG) is a method of measuring brainwave activity non-invasively. A number of electrodes are placed around the head and scalp and electrical signals are measured.<ref name = "Purves_2007">{{cite book | vauthors = Purves D |title=Neuroscience, Fourth Edition |publisher=Sinauer Associates, Inc. |year=2007 |isbn=978-0-87893-697-7 |page=715}}</ref> Clinically, EEGs are used to study epilepsy as well as stroke and tumor presence in the brain. [[Electrocorticography]] (ECoG) relies on similar principles but requires invasive implantation of electrodes on the brain's surface to measure local field potentials or action potentials more sensitively.

[[Magnetoencephalography]] (MEG) is another method of measuring activity in the brain by measuring the magnetic fields that arise from electrical currents in the brain.<ref>{{cite web | vauthors = Hämäläinen M |date=November 2007 |title=Magnetoencephalography (MEG) |publisher=Athinoula A. Martinos Center for Biomedical Imaging |url=http://www.nmr.mgh.harvard.edu/martinos/research/technologiesMEG}}</ref> The benefit to using MEG instead of EEG is that these fields are highly localized and give rise to better understanding of how specific loci react to stimulation or if these regions over-activate (as in epileptic seizures).

There are potential uses for EEG and MEG such as charting rehabilitation and improvement after trauma as well as testing neural conductivity in specific regions of epileptics or patients with personality disorders. EEG has been fundamental in understanding the resting brain during sleep.<ref name = "Purves_2007" /> Real-time EEG has been considered for use in [[lie detection]].<ref>{{cite journal | vauthors = Farwell LA, Smith SS | title = Using brain MERMER testing to detect knowledge despite efforts to conceal | journal = Journal of Forensic Sciences | volume = 46 | issue = 1 | pages = 135–43 | date = January 2001 | pmid = 11210899 | doi = 10.1520/JFS14925J | s2cid = 45516709 }}</ref>
Similarly, real-time fMRI is being researched as a method for pain therapy by altering how people perceive pain if they are made aware of how their brain is functioning while in pain. By providing direct and understandable feedback, researchers can help patients with chronic pain decrease their symptoms.<ref name="deCharms2005">{{cite journal |author1-link=Christopher deCharms
|author3-link=Gary H. Glover | vauthors = deCharms RC, Maeda F, Glover GH, Ludlow D, Pauly JM, Soneji D, Gabrieli JD, Mackey SC | display-authors = 6 | title = Control over brain activation and pain learned by using real-time functional MRI | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 102 | issue = 51 | pages = 18626–31 | date = December 2005 | pmid = 16352728 | pmc = 1311906 | doi = 10.1073/pnas.0505210102 | doi-access = free | bibcode = 2005PNAS..10218626D }}</ref>

===Implants===
{{Main|Brain–computer interface|Surface chemistry of neural implants|Neuroprosthetics}}
Neurotechnological implants can be used to record and utilize brain activity to control other devices which provide feedback to the user or replace missing biological functions.<ref>{{cite journal | vauthors = Hochberg LR, Serruya MD, Friehs GM, Mukand JA, Saleh M, Caplan AH, Branner A, Chen D, Penn RD, Donoghue JP | display-authors = 6 | title = Neuronal ensemble control of prosthetic devices by a human with tetraplegia | journal = Nature | volume = 442 | issue = 7099 | pages = 164–71 | date = July 2006 | pmid = 16838014 | doi = 10.1038/nature04970 | s2cid = 4347367 | bibcode = 2006Natur.442..164H }}</ref> The most common neurodevices available for clinical use are deep brain stimulators implanted in the [[subthalamic nucleus]] for patients with [[Parkinson's disease]].<ref name="Gross2008">{{cite journal | vauthors = Gross RE | title = What happened to posteroventral pallidotomy for Parkinson's disease and dystonia? | journal = Neurotherapeutics | volume = 5 | issue = 2 | pages = 281–93 | date = April 2008 | pmid = 18394570 | pmc = 5084170 | doi = 10.1016/j.nurt.2008.02.001 }}</ref>

===Pharmaceuticals===
{{Main|Neuropsychopharmacology}}
Pharmaceuticals play a vital role in maintaining stable brain chemistry, and are the most commonly used neurotechnology by the general public and medicine. Drugs like [[sertraline]], [[methylphenidate]], and [[zolpidem]] act as chemical modulators in the brain, and they allow for normal activity in many people whose brains cannot act normally under physiological conditions. While pharmaceuticals are usually not mentioned and have their own field, the role of pharmaceuticals is perhaps the most far-reaching and commonplace in modern society. Movement of magnetic particles to targeted brain regions for drug delivery is an emerging field of study and causes no detectable circuit damage.<ref name=":0" />

==Ethical considerations==
{{See also|Neuroethics|Brain implant#Concerns and ethical considerations}}
Like other [[disruptive innovation]]s, neurotechnologies have the potential for profound social and legal repercussions, and as such their development and introduction to society raise a series of ethical questions.<ref name=":3">{{Cite news| vauthors = Al-Rodhan N |date=27 May 2021|title=The Rise of Neurotechnology Calls for a Parallel Focus on Neurorights|work=[[Scientific American]]|url=https://www.scientificamerican.com/article/the-rise-of-neurotechnology-calls-for-a-parallel-focus-on-neurorights/|access-date=25 Oct 2021}}</ref><ref name=":4">{{cite journal | vauthors = Bublitz C, Wolkenstein A, Jox RJ, Friedrich O | title = Legal liabilities of BCI-users: Responsibility gaps at the intersection of mind and machine? | journal = International Journal of Law and Psychiatry | volume = 65 | pages = 101399 | date = 2019-07-01 | pmid = 30449603 | doi = 10.1016/j.ijlp.2018.10.002 | url = https://www.sciencedirect.com/science/article/pii/S0160252718300852 | series = Neuroscience, Law, and Ethics | s2cid = 53950001 }}</ref><ref name="pmid29326561" />

Key concerns include the preservation of identity, agency, cognitive liberty and privacy as [[wikt:neuroright#Noun|neurorights]]. While experts agree that these core features of the human experience stand to benefit from the ethical use of neurotechnology, they also make a point of emphasizing the importance of preventively establishing [[Neurolaw|specific regulatory frameworks]] and other mechanisms that protect against inappropriate or unauthorized uses.<ref name=":12" /><ref name=":3" /><ref>{{cite journal | vauthors = Yuste R, Goering S, Arcas BA, Bi G, Carmena JM, Carter A, Fins JJ, Friesen P, Gallant J, Huggins JE, Illes J, Kellmeyer P, Klein E, Marblestone A, Mitchell C, Parens E, Pham M, Rubel A, Sadato N, Sullivan LS, Teicher M, Wasserman D, Wexler A, Whittaker M, Wolpaw J | display-authors = 6 | title = Four ethical priorities for neurotechnologies and AI | journal = Nature | volume = 551 | issue = 7679 | pages = 159–163 | date = November 2017 | pmid = 29120438 | pmc = 8021272 | doi = 10.1038/551159a | bibcode = 2017Natur.551..159Y }}</ref>

=== Identity ===
Identity in this context refers to [[Personal identity#Continuity of consciousness|personal continuity]], described as [[Bodily integrity|bodily]] and mental integrity and their persistence over time. In other words, it is the individual's [[Narrative identity|self-narrative]] and concept of self.

While disruption of identity is not a common goal for neurotechnologies, some techniques can create unwanted shifts that range in severity. For instance, deep brain stimulation is commonly used as treatment for [[Parkinson's disease]] but can have side effects that touch on the concept of identity, such as loss of voice modulation, increased impulsivity or feelings of self-estrangement.<ref name=":12" /><ref>{{cite journal | vauthors = Pham U, Solbakk AK, Skogseid IM, Toft M, Pripp AH, Konglund AE, Andersson S, Haraldsen IR, Aarsland D, Dietrichs E, Malt UF | display-authors = 6 | title = Personality changes after deep brain stimulation in Parkinson's disease | journal = Parkinson's Disease | volume = 2015 | pages = 490507 | date = 2015-01-29 | pmid = 25705545 | pmc = 4325225 | doi = 10.1155/2015/490507 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Pugh J, Maslen H, Savulescu J | title = Deep Brain Stimulation, Authenticity and Value | journal = Cambridge Quarterly of Healthcare Ethics | volume = 26 | issue = 4 | pages = 640–657 | date = October 2017 | pmid = 28937346 | pmc = 5658726 | doi = 10.1017/S0963180117000147 }}</ref><ref>{{Cite journal| vauthors = Gilbert F, Goddard E, Viaña JN, Carter A, Horne M |date=2017-04-03|title=I Miss Being Me: Phenomenological Effects of Deep Brain Stimulation |journal=AJOB Neuroscience|volume=8|issue=2|pages=96–109|doi=10.1080/21507740.2017.1320319|s2cid=55652038|issn=2150-7740|doi-access=free}}</ref> In the case of neural prostheses and brain-computer interfaces, the shift may take the form of an extension of one's sense of self, potentially incorporating the device as an integral part of oneself or expanding the range of sensory and cognitive channels available to the user beyond the traditional [[sense]]s.<ref name=":12" /><ref>{{cite journal | vauthors = Hildt E | title = Multi-Person Brain-To-Brain Interfaces: Ethical Issues | journal = Frontiers in Neuroscience | volume = 13 | pages = 1177 | date = 5 Nov 2019 | pmid = 31827418 | pmc = 6849447 | doi = 10.3389/fnins.2019.01177 | doi-access = free }}</ref>

Part of the difficulty in determining which changes constitute a threat to identity is rooted in its dynamic nature: since one's personality and concept of self is expected to change with time as a result of emotional development and lived experience, it is not easy to identify clear criteria and draw a line between acceptable shifts and problematic changes.<ref name=":12" /><ref name=":2">{{cite journal | vauthors = Baylis F | title = "I Am Who I Am": On the Perceived Threats to Personal Identity from Deep Brain Stimulation | journal = Neuroethics | volume = 6 | issue = 3 | pages = 513–526 | date = 2013-12-01 | pmid = 24273621 | pmc = 3825414 | doi = 10.1007/s12152-011-9137-1  }}</ref> This becomes even harder when dealing with neurotechnologies aimed at influencing psychological processes—such as those designed to recude the symptoms of depression or post-traumatic stress disorder (PTSD) by modulating emotional states or saliency of memories to ease a patient's pain.<ref name=":5">{{cite journal | vauthors = Steinert S, Friedrich O | title = Wired Emotions: Ethical Issues of Affective Brain-Computer Interfaces | journal = Science and Engineering Ethics | volume = 26 | issue = 1 | pages = 351–367 | date = February 2020 | pmid = 30868377 | pmc = 6978299 | doi = 10.1007/s11948-019-00087-2  }}</ref><ref>{{cite journal | vauthors = Bassil KC, Rutten BP, Horstkötter D | title = Biomarkers for PTSD Susceptibility and Resilience, Ethical Issues | journal = AJOB Neuroscience | volume = 10 | issue = 3 | pages = 122–124 | date = 2019-07-03 | pmid = 31361197 | doi = 10.1080/21507740.2019.1632964 | s2cid = 198982833  | url = https://cris.maastrichtuniversity.nl/en/publications/789df5c5-dfda-44be-b7cb-12fb371e4742 }}</ref> Even helping a patient remember, which would seemingly help preserve identity, can be a delicate question: "Forgetting is also important to how a person navigates the world, since it allows the opportunity for both losing track of embarrassing or difficult memories, and focusing on future-oriented activity. Efforts to enhance identity through memory preservation thus run the risk of inadvertently damaging a valuable, if less consciously-driven cognitive process."<ref name=":12" />

=== Agency ===
Although the nuances of its definition are debated in [[Agency (philosophy)|philosophy]] and [[Agency (sociology)|sociology]],<ref>{{Cite book| vauthors = Wilson G, Shpall S |title=[[Stanford Encyclopedia of Philosophy|The Stanford Encyclopedia of Philosophy]]|publisher=Metaphysics Research Lab, [[Stanford University]]|year=2016| veditors = Zalta EN |edition=Winter 2016|chapter=Action|chapter-url= https://plato.stanford.edu/archives/win2016/entries/action/}}</ref> agency is commonly understood as the individual's ability to consciously make and communicate a decision or choice. While identity and agency are distinct, an impairment in agency can in turn undermine personal identity: the subject may no longer be able to substantially modify their own self-narrative, and may therefore lose their ability to contribute to the dynamic process of identity formation.<ref name=":2" />

The interplay between agency and neurotechnology can have implications for moral responsibility and legal liability.<ref>{{Cite journal| vauthors = Haselager P |date=2013-08-01|title=Did I Do That? Brain–Computer Interfacing and the Sense of Agency|journal=Minds and Machines|language=en|volume=23|issue=3|pages=405–418|doi=10.1007/s11023-012-9298-7|s2cid=7199782|issn=1572-8641|hdl=2066/116450|hdl-access=free}}</ref><ref name=":4" /> As with identity, devices aimed at treating some psychiatric conditions like depression or anorexia may work by modulating neural function linked with desire or motivation, potentially compromising the user's agency.<ref name=":5" /><ref>{{Cite journal| vauthors = Goering S, Klein E, Dougherty DD, Widge AS |date=2017-04-03|title=Staying in the Loop: Relational Agency and Identity in Next-Generation DBS for Psychiatry |journal=AJOB Neuroscience|volume=8|issue=2|pages=59–70|doi=10.1080/21507740.2017.1320320|s2cid=6176406|issn=2150-7740}}</ref> This can also be the case, paradoxically, for those neurotechnologies designed to restore agency to patients, such as neural prostheses and BCI-mediated [[assistive technology]] like wheelchairs or [[computer accessibility]] tools.<ref>{{cite journal | vauthors = Sellers EW, Vaughan TM, Wolpaw JR | title = A brain-computer interface for long-term independent home use | journal = Amyotrophic Lateral Sclerosis | volume = 11 | issue = 5 | pages = 449–55 | date = October 2010 | pmid = 20583947 | doi = 10.3109/17482961003777470 | s2cid = 4713118  }}</ref><ref>{{cite journal | vauthors = Ajiboye AB, Willett FR, Young DR, Memberg WD, Murphy BA, Miller JP, Walter BL, Sweet JA, Hoyen HA, Keith MW, Peckham PH, Simeral JD, Donoghue JP, Hochberg LR, Kirsch RF | display-authors = 6 | title = Restoration of reaching and grasping movements through brain-controlled muscle stimulation in a person with tetraplegia: a proof-of-concept demonstration | journal = Lancet | volume = 389 | issue = 10081 | pages = 1821–1830 | date = May 2017 | pmid = 28363483 | pmc = 5516547 | doi = 10.1016/s0140-6736(17)30601-3}}</ref> Because these devices often operate by interpreting sensory inputs or the user's neural data in order to estimate the individual's intention and respond according to it, estimation margins can lead to inaccurate or undesired responses that may threaten agency: "If the agent's intent and the device's output can come apart (think of how the auto-correct function in texting sometimes misinterprets the user's intent and sends problematic text messages), the user's sense of agency may be undermined."<ref name=":12" />

===Privacy===
Finally, when these technologies are being developed society must understand that these neurotechnologies could reveal the one thing that people can always keep secret: what they are thinking. While there are large amounts of benefits associated with these technologies, it is necessary for scientists, citizens and policy makers alike to consider implications for privacy.<ref name="Wolpe2005">{{cite journal | vauthors = Wolpe PR, Foster KR, Langleben DD | title = Emerging neurotechnologies for lie-detection: promises and perils | journal = The American Journal of Bioethics | volume = 5 | issue = 2 | pages = 39–49 | year = 2005 | pmid = 16036700 | doi = 10.1080/15265160590923367 | url = https://repository.upenn.edu/cgi/viewcontent.cgi?article=1005&context=neuroethics_pubs | s2cid = 219640810 }}</ref> This term is important in many ethical circles concerned with the state and goals of progress in the field of neurotechnology (see [[neuroethics]]). Current improvements such as "brain fingerprinting" or lie detection using EEG or fMRI could give rise to a set fixture of loci/emotional relationships in the brain, although these technologies are still years away from full application.<ref name="Wolpe2005"/> It is important to consider how all these neurotechnologies might affect the future of society, and it is suggested that political, scientific, and civil debates are heard about the implementation of these newer technologies that potentially offer a new wealth of once-private information.<ref name="Wolpe2005"/> Some ethicists are also concerned with the use of TMS and fear that the technique could be used to alter patients in ways that are undesired by the patient.<ref name="Illes2006" />

===Cognitive liberty===
[[Cognitive liberty]] refers to a suggested right to [[self-determination]] of individuals to control their own mental processes, cognition, and consciousness including by the use of various neurotechnologies and psychoactive substances. This perceived right is relevant for reformation and development of associated laws.

== See also ==
* [[Biotechnology]]
* [[Neural engineering]]
* [[Neuroimaging]]
* [[Neuroscience]]

== References ==
{{reflist|30em}}

{{BCI}}
{{Neuroscience}}

[[Category:Neurotechnology| ]]