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Tomás Ryan

Tomás Ryan


  • CIFAR Azrieli Global Scholar 2020-2022
  • Child & Brain Development




How are memories stored in the brain as information? Memory is crucial to everyday life and allows us to adapt to our changing environment.

Diseases of memory range from disorders of transience, e.g. Alzheimer’s disease, to disorders of persistence, e.g. post-traumatic stress disorder. Understanding the basic neurobiology of memory storage in health is crucial to the diagnosis and treatment of clinical conditions. The physical site of a specific memory in the brain, the memory engram, was originally hypothesized to be encoded in the learning-induced persistent changes of specific brain cells that retain information and are subsequently reactivated during remembering. Until recently neuroscience has investigated memory engrams indirectly.Traditional experimental approaches have focused on investigating the role of brain regions, circuits, and molecules in the capacity of memory formation in general. In contrast, comparatively few studies have investigated how specific memory engrams are stored in the brain. Engram cell-labeling technology has revolutionized the way memory can be studied, allowing us to test long-standing but unproven theories of memory storage. Using genetic methods we can now label specific memory engram cells in the mouse brain, and then reversibly control them in awake behaving mice. Tomás Ryan’s research group aims to understand how memory engrams change over development and how they interact with innate representations. His research program aims to understand how memories and instincts can interact to enable adaptive behaviour.


  • 2018 – Admitted to Federation of European Neuroscience Societies (FENS)-Kavli Network of Excellence
  • 2018 – Early Career Researcher of the Year Award Science Foundation Ireland (SFI)
  • 2017 – European Research Council (ERC) Starting Grant, European Research Council, European Union
  • 2017 – President of Ireland Future Leader Award, Science Foundation Ireland (SFI), Ireland
  • 2017 – Jacobs Foundation Research Fellowship, Jacobs Foundation, Switzerland

Relevant Publications

  • Ryan TJ. (2020) Memory and Instinct as a Continuum of Information Storage. The Cognitive Neurosciences (6th Edition), MIT Press (2020)
  • Pignatelli M*, Ryan TJ*, Roy DS, Lovett C, Smith LM, Muralidhar S, Tonegawa S. (2018) Engram Cell Excitability State Determines the Efficacy of Memory Retrieval. Neuron Jan 16;101(2):274-284 Epub 2018 Dec 11* Joint first author
  • Ryan TJ*, Roy DS*, Pignatelli M*, Arons A, Tonegawa S. (2015) Engram cells retain memory under retrograde amnesia. Science, May 29, 348(6238):1007-13 *Joint first author* Joint first author
  • Tonegawa S, Pignatelli M, Roy DS, Ryan TJ. (2015) Memory engram storage and retrieval. Current Opinion in Neurobiology, Aug 13, 35:101-09
  • Ryan TJ, Kopanitsa MV, Indersmitten T, Nithianantharajah J, Afinowi NO, Pettit C, Stanford LE, Sprengel R, Saksida LM, Bussey TJ, O'Dell TJ, Grant SG, Komiyama NH. (2012) Evolution of GluN2A/B

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