Editing Neuroscience (section)

==Modern neuroscience==
{{main|Outline of neuroscience}}
[[File:Nervous system diagram-en.svg|thumb|upright=1.3|Human nervous system]]

The [[scientific method|scientific study]] of the nervous system increased significantly during the second half of the twentieth century, principally due to advances in [[molecular biology]], [[electrophysiology]], and [[computational neuroscience]]. This has allowed neuroscientists to study the [[nervous system]] in all its aspects: how it is structured, how it works, how it develops, how it malfunctions, and how it can be changed.

For example, it has become possible to understand, in much detail, the complex processes occurring within a single [[neuron]]. Neurons are cells specialized for communication. They are able to communicate with neurons and other cell types through specialized junctions called [[synapse]]s, at which electrical or electrochemical signals can be transmitted from one cell to another. Many neurons extrude a long thin filament of [[axoplasm]] called an [[axon]], which may extend to distant parts of the body and are capable of rapidly carrying electrical signals, influencing the activity of other neurons, muscles, or glands at their termination points. A nervous ''system'' emerges from the assemblage of neurons that are connected to each other in [[neural circuit]]s, and [[Neural network (biology)|networks]].

The vertebrate nervous system can be split into two parts: the [[central nervous system]] (defined as the [[brain]] and [[spinal cord]]), and the [[peripheral nervous system]]. In many species—including all vertebrates—the nervous system is the most [[Complex system|complex organ system]] in the body, with most of the complexity residing in the brain. The [[human brain]] alone contains around one hundred billion neurons and one hundred trillion synapses; it consists of thousands of distinguishable substructures, connected to each other in synaptic networks whose intricacies have only begun to be unraveled. At least one out of three of the approximately 20,000 genes belonging to the human genome is expressed mainly in the brain.<ref>{{Cite web |title=Brain Basics: Genes At Work In The Brain {{!}} National Institute of Neurological Disorders and Stroke |url=https://www.ninds.nih.gov/health-information/patient-caregiver-education/brain-basics-genes-work-brain |access-date=2025-04-11 |website=www.ninds.nih.gov |language=en}}</ref>

Due to the high degree of [[neuroplasticity|plasticity]] of the human brain, the structure of its synapses and their resulting functions change throughout life.<ref>{{Cite web |title=The Fundamentals of Mental Health and Mental Illness |url=https://resources.saylor.org/wwwresources/archived/site/wp-content/uploads/2011/07/psych205-2.2.pdf |website=resources.saylor.org}}</ref>

Making sense of the nervous system's dynamic complexity is a formidable research challenge. Ultimately, neuroscientists would like to understand every aspect of the nervous system, including how it works, how it develops, how it malfunctions, and how it can be altered or repaired. Analysis of the nervous system is therefore performed at multiple levels, ranging from the molecular and cellular levels to the systems and cognitive levels. The specific topics that form the main focus of research change over time, driven by an ever-expanding base of knowledge and the availability of increasingly sophisticated technical methods. Improvements in technology have been the primary drivers of progress. Developments in [[electron microscopy]], [[computer science]], [[electronics]], [[functional neuroimaging]], and [[genetics]] and [[genomics]] have all been major drivers of progress.

Advances in the classification of [[brain cell]]s have been enabled by electrophysiological recording, [[Single-cell sequencing|single-cell genetic sequencing]], and high-quality microscopy, which have combined into a single method pipeline called [[patch-sequencing]] in which all three methods are simultaneously applied using miniature tools.<ref>{{cite journal |last1=Lipovsek |first1=Marcela |last2=Bardy |first2=Cedric |last3=Cadwell |first3=Cathryn R.|display-authors=etal |title=Patch-seq: Past, Present, and Future |journal=The Journal of Neuroscience |date=3 February 2021 |volume=41 |issue=5 |pages=937–946 |doi=10.1523/JNEUROSCI.1653-20.2020 |pmid=33431632 |pmc=7880286 }}</ref> The efficiency of this method and the large amounts of data that is generated has allowed researchers to make some general conclusions about cell types; for example that the human and mouse brain have different versions of fundamentally the same cell types.<ref>{{cite journal |last1=Hodge |first1=Rebecca D. |last2=Bakken |first2=Trygve E. |last3=Miller |first3=Jeremy A. |display-authors=etal|title=Conserved cell types with divergent features in human versus mouse cortex |journal=Nature |date=5 September 2019 |volume=573 |issue=7772 |pages=61–68 |doi=10.1038/s41586-019-1506-7 |pmid=31435019 |pmc=6919571 |bibcode=2019Natur.573...61H }}</ref>

===Molecular and cellular neuroscience===
{{main|Molecular neuroscience|Cellular neuroscience}}[[Image:neuron colored.jpg|right|thumb|200px|Photograph of a [[staining|stained neuron]] in a chicken embryo]]

Basic questions addressed in [[molecular neuroscience]] include the mechanisms by which neurons express and respond to molecular signals and how [[axon]]s form complex connectivity patterns. At this level, tools from [[molecular biology]] and [[genetics]] are used to understand how neurons develop and how genetic changes affect biological functions.<ref>{{cite web|url=https://neuroscience.ucsb.edu/research/molecular-and-cellular-neuroscience |title=Molecular and Cellular Neuroscience &#124; UCSB Neuroscience &#124; UC Santa Barbara |publisher=Neuroscience.ucsb.edu |access-date=2022-08-03}}</ref> The [[morphology (biology)|morphology]], molecular identity, and physiological characteristics of neurons and how they relate to different types of behavior are also of considerable interest.<ref>{{cite book |doi=10.1016/C2011-0-07251-4 |title=From Molecules to Networks |date=2014 |publisher=Elsevier |isbn=978-0-12-397179-1 |editor1-first=John H. |editor1-last=Byrne |editor2-first=Ruth |editor2-last=Heidelberger |editor3-first=M. Neal |editor3-last=Waxham }}{{pn|date=March 2025}}</ref>

Questions addressed in [[cellular neuroscience]] include the mechanisms of how neurons process [[cell signaling|signals]] physiologically and electrochemically. These questions include how signals are processed by neurites and somas and how [[neurotransmitter]]s and electrical signals are used to process information in a neuron. Neurites are thin extensions from a neuronal [[Perikaryon|cell body]], consisting of [[dendrite]]s (specialized to receive synaptic inputs from other neurons) and [[axon]]s (specialized to conduct nerve impulses called [[action potential]]s). Somas are the cell bodies of the neurons and contain the nucleus.<ref>{{cite journal |last1=Flynn |first1=Kevin C |title=The cytoskeleton and neurite initiation |journal=BioArchitecture |date=July 2013 |volume=3 |issue=4 |pages=86–109 |doi=10.4161/bioa.26259 |pmid=24002528 |pmc=4201609 }}</ref>

Another major area of cellular neuroscience is the investigation of the [[development of the nervous system]].<ref>{{cite book |last1=Alberts |first1=Bruce |last2=Johnson |first2=Alexander |last3=Lewis |first3=Julian |last4=Raff |first4=Martin |last5=Roberts |first5=Keith |last6=Walter |first6=Peter |title=Molecular Biology of the Cell |date=2002 |publisher=Garland Science |location=New York |isbn=9780815332183 |edition=4 |url=https://www.ncbi.nlm.nih.gov/books/NBK26814/ |access-date=7 August 2023 |chapter=Neural Development}}</ref> Questions include the [[Regional specification|patterning and regionalization]] of the nervous system, axonal and dendritic development, [[Growth factor|trophic interactions]], [[Synaptogenesis|synapse formation]] and the implication of [[fractone]]s in [[neural stem cell]]s,<ref>{{Cite journal |last1=Nascimento |first1=Marcos Assis |last2=Sorokin |first2=Lydia |last3=Coelho-Sampaio |first3=Tatiana |date=2018-04-18 |title=Fractone Bulbs Derive from Ependymal Cells and Their Laminin Composition Influence the Stem Cell Niche in the Subventricular Zone |url=https://www.jneurosci.org/content/38/16/3880 |journal=Journal of Neuroscience |language=en |volume=38 |issue=16 |pages=3880–3889 |doi=10.1523/JNEUROSCI.3064-17.2018 |issn=0270-6474 |pmc=6705924 |pmid=29530987}}</ref><ref>{{Cite journal |last=Mercier |first=Frederic |date=2016 |title=Fractones: extracellular matrix niche controlling stem cell fate and growth factor activity in the brain in health and disease |journal=Cellular and Molecular Life Sciences |language=en |volume=73 |issue=24 |pages=4661–4674 |doi=10.1007/s00018-016-2314-y |pmid=27475964 |pmc=11108427 |s2cid=28119663 |issn=1420-682X}}</ref> [[Cellular differentiation|differentiation]] of neurons and glia ([[neurogenesis]] and [[gliogenesis]]), and [[neuronal migration]].<ref>{{Cite journal |last1=Mercier |first1=Frederic |last2=Arikawa-Hirasawa |first2=Eri |date=2012 |title=Heparan sulfate niche for cell proliferation in the adult brain |url=https://linkinghub.elsevier.com/retrieve/pii/S0304394011016685 |journal=Neuroscience Letters |language=en |volume=510 |issue=2 |pages=67–72 |doi=10.1016/j.neulet.2011.12.046|pmid=22230891 |s2cid=27352770 |url-access=subscription }}</ref>

[[Computational neurogenetic modeling]] is concerned with the development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes, on the cellular level (Computational Neurogenetic Modeling (CNGM) can also be used to model neural systems).<ref>{{cite web |title=Neuroscience Research Areas |url=https://med.nyu.edu/departments-institutes/neuroscience/research/research-areas |website=NYU Grossman School of Medicine |publisher=NYU Langone Health Neuroscience Institute |access-date=7 August 2023}}</ref>

===Neural circuits and systems===
{{main|Neural circuit|Systems neuroscience}}[[File:Leg Neural Network.jpg|thumb|Proposed organization of motor-semantic neural circuits for action language comprehension. Adapted from Shebani et al. (2013).]]

[[Systems neuroscience]] research centers on the structural and functional architecture of the developing human brain, and the functions of [[large-scale brain network]]s, or functionally-connected systems within e brain. Alongside brain development, systems neuroscience also focuses on how the structure and function of the brain enables or restricts the processing of sensory information, using learned [[mental model]]s of the world, to motivate behavior.

Questions in systems neuroscience include how [[neural circuit]]s are formed and used anatomically and physiologically to produce functions such as [[reflex]]es, [[multisensory integration]], [[motor coordination]], [[circadian rhythm]]s, [[emotion|emotional responses]], [[learning]], and [[memory]].<ref>{{cite journal |last1=Tau |first1=Gregory Z |last2=Peterson |first2=Bradley S |title=Normal Development of Brain Circuits |journal=Neuropsychopharmacology |date=January 2010 |volume=35 |issue=1 |pages=147–168 |doi=10.1038/npp.2009.115|pmid=19794405 |pmc=3055433 }}</ref> In other words, this area of research studies how connections are made and morphed in the brain, and the effect it has on human sensation, movement, attention, inhibitory control, decision-making, reasoning, memory formation, reward, and emotion regulation.<ref>{{cite journal |last1=Menon |first1=Vinod |title=Large-scale brain networks and psychopathology: a unifying triple network model |journal=Trends in Cognitive Sciences |date=October 2011 |volume=15 |issue=10 |pages=483–506 |doi=10.1016/j.tics.2011.08.003 |pmid=21908230 |s2cid=26653572 |url=https://doi.org/10.1016/j.tics.2011.08.003 |access-date=8 August 2023|url-access=subscription }}</ref>

Specific areas of interest for the field include observations of how the structure of neural circuits effect skill acquisition, how specialized regions of the brain develop and change ([[neuroplasticity]]), and the development of brain atlases, or wiring diagrams of individual developing brains.<ref>{{cite book |last1=Menon |first1=Vinod |editor1-last=Hopkins |editor1-first=Brian |editor2-last=Barr |editor2-first=Ronald G. |title=Cambridge Encyclopedia of Child Development |date=2017 |publisher=Cambridge University Press |edition=2nd |url=https://search.credoreference.com/articles/Qm9va0FydGljbGU6NDYwODM4 |access-date=25 September 2023 |chapter=Systems neuroscience}}</ref>

The related fields of [[neuroethology]] and [[neuropsychology]] address the question of how neural substrates underlie specific [[Ethology|animal]] and [[human behavior|human]] behaviors.<ref>{{cite book |editor1-last=Craighead |editor1-first=W. Edward |editor2-last=Nemeroff |editor2-first=Charles B. |editor2-link=Charles Nemeroff |title=The Concise Corsini Encyclopedia of Psychology and Behavioral Science |date=2004 |publisher=Wiley |url=https://search.credoreference.com/articles/Qm9va0FydGljbGU6MTY2ODQ3OA==. |access-date=25 September 2023 |chapter=Neuroethology}}</ref> [[Neuroendocrinology]] and [[psychoneuroimmunology]] examine interactions between the nervous system and the [[endocrinology|endocrine]] and [[immunology|immune]] systems, respectively.<ref>{{cite book |last1=Solberg Nes |first1=Lise |last2=Segerstrom |first2=Suzanne C. |author2-link=Suzanne Segerstrom |editor1-last=Spielberger |editor1-first=Charles Donald |title=Encyclopedia of Applied Psychology |publisher=Elsevier Science & Technology |edition=1st |url=https://search.credoreference.com/articles/Qm9va0FydGljbGU6MjkzOTIxMQ== |access-date=25 September 2023 |chapter=Psychoneuroimmunology}}</ref> Despite many advancements, the way that networks of neurons perform complex [[cognition|cognitive processe]]s and behaviors is still poorly understood.<ref>{{cite book |last1=Kaczmarek |first1=Leonard K |last2=Nadel |first2=L. |title=Encyclopedia of Cognitive Science |date=2005 |publisher=Wiley |edition=1st |url=https://search.credoreference.com/articles/Qm9va0FydGljbGU6Mjg2NjA0 |access-date=25 September 2023 |chapter=Neuron Doctrine}}</ref>

===Cognitive and behavioral neuroscience===
{{main|Behavioral neuroscience|Cognitive neuroscience}}

[[Cognitive neuroscience]] addresses the questions of how [[mental process|psychological functions]] are produced by [[biological neural network|neural circuitry]]. The emergence of powerful new measurement techniques such as [[neuroimaging]] (e.g., [[fMRI]], [[Positron emission tomography|PET]], [[SPECT]]), [[electroencephalography|EEG]], [[Magnetoencephalography|MEG]], [[electrophysiology]], [[optogenetics]] and [[Human genome|human genetic analysis]] combined with sophisticated [[experimental techniques]] from [[cognitive psychology]] allows [[neuroscientist]]s and [[psychologist]]s to address abstract questions such as how cognition and emotion are mapped to specific neural substrates. Although many studies hold a reductionist stance looking for the neurobiological basis of cognitive phenomena, recent research shows that there is an interplay between neuroscientific findings and conceptual research, soliciting and integrating both perspectives. For example, neuroscience research on empathy solicited an interdisciplinary debate involving philosophy, psychology and psychopathology.<ref>Aragona M, Kotzalidis GD, Puzella A. (2013) [http://www.archivespp.pl/uploads/images/2013_15_4/5Aragona_APP_4_2013.pdf The many faces of empathy, between phenomenology and neuroscience] {{Webarchive|url=https://web.archive.org/web/20201002093723/http://www.archivespp.pl/uploads/images/2013_15_4/5Aragona_APP_4_2013.pdf |date=2020-10-02 }}. Archives of Psychiatry and Psychotherapy, 4:5-12</ref> Moreover, the neuroscientific identification of multiple memory systems related to different brain areas has challenged the idea of [[memory]] as a literal reproduction of the past, supporting a view of memory as a generative, constructive and dynamic process.<ref>{{cite journal |last1=Ofengenden |first1=Tzofit |year=2014 |title=Memory formation and belief |url=http://www.crossingdialogues.com/Ms-A14-03.pdf |journal=Dialogues in Philosophy, Mental and Neuro Sciences |volume=7 |issue=2 |pages=34–44}}</ref>

Neuroscience is also allied with the [[social science|social]] and [[behavioral sciences]], as well as with nascent interdisciplinary fields. Examples of such alliances include [[neuroeconomics]], [[decision theory]], [[social neuroscience]], and [[neuromarketing]] to address complex questions about interactions of the brain with its environment. A study into consumer responses for example uses EEG to investigate neural correlates associated with [[Transportation theory (psychology)|narrative transportation]] into stories about [[Efficient energy use|energy efficiency]].<ref>{{Cite journal | doi=10.1108/EJM-12-2016-0881|title = Using EEG to examine the role of attention, working memory, emotion, and imagination in narrative transportation| journal=European Journal of Marketing| volume=52| pages=92–117|year = 2018|last1 = Gordon|first1 = Ross| last2=Ciorciari| first2=Joseph| last3=Van Laer| first3=Tom |ssrn=2892967|url = https://openaccess.city.ac.uk/id/eprint/18069/1/PDF_Proof.PDF}}</ref>

===Computational neuroscience===
{{main|Computational neuroscience}}

Questions in computational neuroscience can span a wide range of levels of traditional analysis, such as [[developmental neuroscience|development]], [[neuroanatomy|structure]], and [[cognitive neuroscience|cognitive functions]] of the brain. Research in this field utilizes [[mathematical models]], theoretical analysis, and [[computer simulation]] to describe and verify biologically plausible neurons and nervous systems. For example, [[biological neuron models]] are mathematical descriptions of spiking neurons which can be used to describe both the behavior of single neurons as well as the dynamics of [[neural networks (biology)|neural networks]]. Computational neuroscience is often referred to as theoretical neuroscience.

===Neuroscience and medicine===

====Clinical neuroscience====
{{Main|Neurotherapy}}
{{Further|Clinical neuroscience}}
Neurology, psychiatry, neurosurgery, psychosurgery, anesthesiology and [[pain medicine]], neuropathology, [[neuroradiology]], [[ophthalmology]], [[otolaryngology]], [[clinical neurophysiology]], [[addiction medicine]], and [[sleep medicine]] are some medical specialties that specifically address the diseases of the nervous system. These terms also refer to clinical disciplines involving diagnosis and treatment of these diseases.<ref>{{cite web |title=Neurologic Diseases |url=https://medlineplus.gov/neurologicdiseases.html |website=medlineplus.gov |publisher=National Library of Medicine (NIH) |access-date=25 September 2023}}</ref>

[[Neurology]] works with diseases of the central and peripheral nervous systems, such as [[amyotrophic lateral sclerosis]] (ALS) and [[stroke]], and their medical treatment. [[Psychiatry]] focuses on [[Affect (psychology)|affective]], behavioral, [[cognition|cognitive]], and [[perception|perceptual]] disorders. [[Anesthesiology]] focuses on perception of pain, and pharmacologic alteration of consciousness. [[Neuropathology]] focuses upon the classification and underlying pathogenic mechanisms of central and peripheral nervous system and muscle diseases, with an emphasis on morphologic, microscopic, and chemically observable alterations. [[Neurosurgery]] and [[psychosurgery]] work primarily with surgical treatment of diseases of the central and peripheral nervous systems.<ref>{{cite book |title=A.D.A.M. Medical Encyclopedia |date=2021 |publisher=Ebix, inc. |location=Johns Creek (GA) |url=https://medlineplus.gov/ency/article/007456.htm |access-date=25 September 2023 |language=en |chapter=Neurosciences}}</ref>

Neuroscience underlies the development of various [[neurotherapy]] methods to treat diseases of the nervous system.<ref name="EEE Brain 2019">IEEE Brain (2019). "Neurotherapy: Treating Disorders by Retraining the Brain". ''The Future Neural Therapeutics White Paper''. Retrieved 23.01.2025 from: https://brain.ieee.org/topics/neurotherapy-treating-disorders-by-retraining-the-brain/#:~:text=Neurotherapy%20trains%20a%20patient's%20brain,wave%20activity%20through%20positive%20reinforcement </ref><ref name="International Neuromodulation Society_2024">International Neuromodulation Society, Retrieved 23 January 2025 from: https://www.neuromodulation.com/ </ref><ref name="Val Danilov Origin Neurostimulation_2024">Val Danilov I (2023). "The Origin of Natural Neurostimulation: A Narrative Review of Noninvasive Brain Stimulation Techniques." ''OBM Neurobiology'' 2024; 8(4): 260; https://doi:10.21926/obm.neurobiol.2404260.</ref>

====Translational research====
{{Further|Translational research |Translational neuroscience}}
[[Image:Parasagittal MRI of human head in patient with benign familial macrocephaly prior to brain injury (ANIMATED).gif|right|thumb|An [[MRI]] of a human head showing [[Macrocephaly#Benign or familial macrocephaly|benign familial macrocephaly]] (head circumference > 60 cm)]]

Recently, the boundaries between various specialties have blurred, as they are all influenced by [[basic research]] in neuroscience. For example, [[brain imaging]] enables objective biological insight into mental illnesses, which can lead to faster diagnosis, more accurate prognosis, and improved monitoring of patient progress over time.<ref>{{cite web|author=Lepage M |date=2010 |title=Research at the Brain Imaging Centre |work=Douglas Mental Health University Institute |url=http://www.douglas.qc.ca/page/imagerie-cerebrale?locale=en |url-status=dead |archive-url=https://web.archive.org/web/20120305042011/http://www.douglas.qc.ca/page/imagerie-cerebrale?locale=en |archive-date=March 5, 2012}}</ref>

[[Integrative neuroscience]] describes the effort to combine models and information from multiple levels of research to develop a coherent model of the nervous system. For example, brain imaging coupled with physiological numerical models and theories of fundamental mechanisms may shed light on psychiatric disorders.<ref name="gordon2003">{{cite journal|author=Gordon E|title=Integrative neuroscience.|journal=Neuropsychopharmacology|year=2003|volume=28|issue=Suppl 1 |pages=S2-8|pmid=12827137| doi=10.1038/sj.npp.1300136|doi-access=free}}</ref>

Another important area of translational research is [[brain–computer interface]]s (BCIs), or machines that are able to communicate and influence the brain. They are currently being researched for their potential to repair neural systems and restore certain cognitive functions.<ref>{{cite journal |last1=Krucoff |first1=Max O. |last2=Rahimpour |first2=Shervin |last3=Slutzky |first3=Marc W. |last4=Edgerton |first4=V. Reggie |last5=Turner |first5=Dennis A. |title=Enhancing Nervous System Recovery through Neurobiologics, Neural Interface Training, and Neurorehabilitation |journal=Frontiers in Neuroscience |date=27 December 2016 |volume=10 |page=584 |doi=10.3389/fnins.2016.00584 |pmid=28082858 |pmc=5186786 |doi-access=free }}</ref> However, some ethical considerations have to be dealt with before they are accepted.<ref>{{cite journal |last1=Haselager |first1=Pim |last2=Vlek |first2=Rutger |last3=Hill |first3=Jeremy |last4=Nijboer |first4=Femke |title=A note on ethical aspects of BCI |journal=Neural Networks |date=1 November 2009 |volume=22 |issue=9 |pages=1352–1357 |doi=10.1016/j.neunet.2009.06.046 |pmid=19616405 |hdl=2066/77533 |hdl-access=free }}</ref><ref>{{cite journal |last1=Nijboer |first1=Femke |last2=Clausen |first2=Jens |last3=Allison |first3=Brendan Z. |last4=Haselager |first4=Pim |title=The Asilomar Survey: Stakeholders' Opinions on Ethical Issues Related to Brain–Computer Interfacing |journal=Neuroethics |date=2013 |volume=6 |issue=3 |pages=541–578 |doi=10.1007/s12152-011-9132-6 |pmid=24273623 |pmc=3825606 }}</ref>