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    Karl Deisseroth

    Also known as Karl A. Deisseroth

    Karl Deisseroth is a Stanford University bioengineer and psychiatrist who turned an algal light-sensitive protein into a switch for nerve cells, the basis of optogenetics.[1][2] On 5 October 2026 he was awarded the Nobel Prize in Physiology or Medicine, shared with Peter Hegemann and Georg Nagel, for discoveries concerning light-gated ion channels and optogenetics.[3]

    Editor reviewedStrict sourcingUpdated WikiNeuroscience and brain-computer interfaces, Health and medicine, Life sciences
    Key facts

    Karl Deisseroth is a physician-scientist at Stanford University and the Howard Hughes Medical Institute who works across bioengineering and psychiatry.[2] He is in the news because he shares the 2026 Nobel Prize in Physiology or Medicine for optogenetics, a method of switching nerve cells on and off with light.[3][4] This page covers his public scientific record. It is for information only and is not medical advice; anyone concerned about a mental-health condition should talk to a clinician.

    The 2026 Nobel Prize

    On 5 October 2026 the Nobel Assembly at Karolinska Institutet awarded the prize jointly to Deisseroth, Peter Hegemann and Georg Nagel “for their discoveries concerning light-gated ion channels and optogenetics”.[3] The committee credits Hegemann and Nagel with discovering channelrhodopsin, a protein from a single-celled alga, and Deisseroth with turning it into a light-controlled switch for nerve cells.[1] The prize is 12 million Swedish kronor, shared equally.[5] Deisseroth said he lost the ability to form words for about 30 seconds when he heard the news.[6]

    Career

    Deisseroth was born in Boston on 18 November 1971.[7] He earned a PhD in 1998 and an MD in 2000 at Stanford, where he is now the D.H. Chen Professor and a professor of bioengineering and of psychiatry and behavioral sciences.[2] He has been an HHMI Investigator since 2014. HHMI describes his lab’s ultimate aim as understanding both normal circuit dynamics and the faulty circuit dynamics behind neuropsychiatric disease.[8]

    He first planned to become a neurosurgeon but changed course during his psychiatry rotation.[9] According to the Nobel committee, he went looking for new tools because the treatments he could offer patients were rarely effective and often had debilitating side effects.[9]

    Optogenetics

    Deisseroth put the channelrhodopsin gene into rat nerve cells and set off nerve signals with blue light. He published the result in 2005, and two years later made the method work in living mice.[10] The 2005 paper, with co-authors Boyden, Zhang, Bamberg and Nagel, reported reliable, millisecond-timescale control of neuron firing.[11] Stanford says he then ran a training program that taught thousands of scientists the method and sent the engineered opsin gene to labs around the world.[12] For how the method works and what it has found, see optogenetics.

    CLARITY and brain mapping

    In 2013 his group, with Kwanghun Chung as first author, published CLARITY. The method turns intact tissue into a transparent, hydrogel-hybridized form that can be imaged without slicing it.[13] It replaces the light-blocking lipids in brain tissue with hydrogel while keeping structural and molecular information, and Stanford says Deisseroth is working towards a transparent human brain.[14] The 2013 paper also applied CLARITY to human tissue from a neuropsychiatric-disease setting.[13] For the wider field, see how brain mapping works.

    Relevance to mental-health research

    Much of his lab’s psychiatric work is in animals. In 2013 it reported that inhibiting or exciting specific midbrain dopamine neurons in rodents immediately induced or relieved several depression-like symptoms caused by chronic stress.[15] A 2020 study found that ketamine set off a slow rhythm in a part of the mouse cortex, and that driving this rhythm with light reproduced dissociation-like behaviour. A similar rhythm in one epilepsy patient tracked self-reported dissociation.[16] He has also shown that heart rhythm can feed into anxiety.[17] Stanford says that with UCSF’s Anatol Kreitzer he reversed Parkinson’s symptoms in mice, and that his team found a circuit controlling social interaction in mice.[18]

    Work in people is newer. In November 2023 he and colleagues launched Stanford’s Human Neural Circuitry program. It studies real-time brain activity from patients who already have electrodes placed for their medical care.[19] Stanford says he hopes this work will eventually help treat Parkinson’s, schizophrenia, autism, addiction, depression and anxiety.[20] As of October 2026, the clinical trials of optogenetics that the Nobel committee describes aim to restore vision, not to treat psychiatric illness.[21] Our analysis From optogenetics to psychiatry weighs how close those treatments are.

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    Questions readers ask

    Why did Karl Deisseroth win the Nobel Prize?

    The 2026 Nobel Prize in Physiology or Medicine was awarded to Deisseroth, Peter Hegemann and Georg Nagel for discoveries concerning light-gated ion channels and optogenetics. Hegemann and Nagel discovered channelrhodopsin in an alga; Deisseroth turned it into a light-controlled switch for nerve cells.[3][1]

    Is Karl Deisseroth a psychiatrist?

    Yes. He holds an MD and a PhD from Stanford and is a professor of psychiatry and behavioral sciences as well as of bioengineering. The Nobel committee says the limits of treatments for his psychiatric patients drove his search for better tools.[2][9]

    What is CLARITY?

    CLARITY, published by Deisseroth's group in 2013, turns intact tissue such as a mouse brain into a transparent, hydrogel-hybridized form that can be imaged and labelled without slicing.[13][14]

    Has his work led to treatments for mental illness?

    Not directly yet. His lab has used optogenetics in rodents to switch depression-like symptoms on and off and to find a brain rhythm linked to dissociation. The main clinical use of optogenetics so far is in trials to restore vision.[15][16][21]

    How much is the 2026 Nobel Prize worth?

    The prize is 12 million Swedish kronor, shared equally between the three laureates.[5]

    Sources

    · 21 claims from 8 publishers

    Each numbered claim is a statement we checked against the sources listed with it. Tap a number in the text to see its sources in place.

    1. [1]

      The Nobel committee credits Hegemann and Nagel with discovering channelrhodopsin, a protein from a single-celled alga, and Deisseroth with transforming it into a light-controlled switch for nerve cells. confirmedas of 2026-10-05

    2. [2]

      Deisseroth earned a PhD in 1998 and an MD in 2000 from Stanford University, and is the D.H. Chen Professor and professor of bioengineering and of psychiatry and behavioral sciences at Stanford and the Howard Hughes Medical Institute. confirmedas of 2026-10-05

    3. [3]

      On 5 October 2026 the Nobel Assembly at Karolinska Institutet awarded the 2026 Nobel Prize in Physiology or Medicine jointly to Karl Deisseroth, Peter Hegemann and Georg Nagel "for their discoveries concerning light-gated ion channels and optogenetics". confirmedas of 2026-10-05

    4. [4]

      Optogenetics uses light-sensitive proteins called opsins, originally found in microbes, inserted into chosen nerve cells so that light can switch those cells on or off in a living brain. confirmedas of 2026-10-05

    5. [5]

      The 2026 medicine prize amount is 12 million Swedish kronor, shared equally between the three laureates. confirmedas of 2026-10-05

    6. [6]

      Deisseroth said that when he learned of the prize he had trouble forming words for about 30 seconds. confirmedas of 2026-10-05

    7. [7]

      Karl Deisseroth was born on 18 November 1971 in Boston, Massachusetts. confirmedas of 2026-10-05

    8. [8]

      Deisseroth has been an HHMI Investigator since 2014; HHMI describes his ultimate aim as understanding the neural circuit dynamics of normal behaviour and the pathological circuit dynamics underlying neuropsychiatric disease. confirmedas of 2026-10-11

    9. [9]

      According to the Nobel committee, Deisseroth considered neurosurgery but was struck by patients' suffering during psychiatric training, and pursued new tools because the treatments he could offer were rarely effective and often had debilitating side effects. confirmedas of 2026-10-05

    10. [10]

      Deisseroth introduced the channelrhodopsin gene into rat nerve cells and triggered nerve signals with blue light, publishing in 2005; two years later he made the method work in the brains of living mice. confirmedas of 2026-10-05

    11. [11]

      The 2005 Nature Neuroscience paper by Boyden, Zhang, Bamberg, Nagel and Deisseroth reported reliable, millisecond-timescale control of neuronal spiking in mammalian neurons using channelrhodopsin-2. confirmedas of 2005-08-14

    12. [12]

      Stanford says Deisseroth set up an optogenetics training program that has taught thousands of scientists and distributed the engineered opsin gene to labs worldwide. confirmedas of 2026-10-05

    13. [13]

      In 2013 Deisseroth's group, with first author Kwanghun Chung, published CLARITY, a method that turns intact tissue into a transparent hydrogel-hybridized form for imaging; the paper also applied it to non-sectioned human tissue from a neuropsychiatric-disease setting. confirmedas of 2013-04-10

    14. [14]

      CLARITY works by replacing light-blocking lipids in brain tissue with a transparent hydrogel while preserving structural and molecular information, and Stanford says Deisseroth is working towards a transparent human brain. confirmedas of 2026-10-05

    15. [15]

      A 2013 Nature study from Deisseroth's lab found that inhibiting or exciting specific midbrain dopamine neurons in rodents immediately induced or relieved multiple depression-like symptoms caused by chronic stress. confirmedas of 2012-12-12

    16. [16]

      A 2020 Nature study led by Deisseroth's lab found that ketamine induced a 1-3 Hz rhythm in retrosplenial cortex of mice, that driving this rhythm optogenetically recreated dissociation-like behaviour, and that a similar rhythm in one epilepsy patient correlated with self-reported dissociation. confirmedas of 2020-09-16

    17. [17]

      Deisseroth has used optogenetics to show that heart rhythm can affect emotion; forcing the heart to work harder can reinforce anxiety-like states. confirmedas of 2026-10-05

    18. [18]

      Stanford says Deisseroth and UCSF researcher Anatol Kreitzer used optogenetics to reverse Parkinson's symptoms in mice, and that his team identified a circuit controlling the desire for social interaction in mice. confirmedas of 2026-10-05

    19. [19]

      In November 2023 Deisseroth and collaborators launched Stanford's Human Neural Circuitry program, which studies real-time brain activity from patients with clinically placed electrodes in a specialised space at Stanford Hospital. confirmedas of 2026-10-05

    20. [20]

      Stanford says Deisseroth ultimately hopes to understand the working brain well enough to treat severe disorders such as Parkinson's, schizophrenia, autism, addiction, depression and anxiety. confirmedas of 2026-10-05

    21. [21]

      As of October 2026 the main clinical use of optogenetics is in trials to restore vision in people blinded by retinitis pigmentosa; in one person, a channelrhodopsin-like protein plus light-emitting glasses restored enough vision to locate and grasp objects. confirmedas of 2026-10-05

    Revision history (1)
    1. Page created.

    Created Oct 11, 2026. Last reviewed by an editor on Oct 11, 2026. Next scheduled review: Dec 11, 2026.

    Cite this page

    "Karl Deisseroth." ContentLora, updated Oct 11, 2026. https://contentlora.com/wiki/karl-deisseroth

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