Traduction: G.M.
Proc Natl Acad Sci U S A. 2017 Jun 13. pii: 201701812. doi: 10.1073/pnas.1701812114.
Inhibitory engrams in perception and memory
Barron HC1,2, Vogels TP3, Behrens TE1,4, Ramaswami M5,6.
Author information
- 1
- The Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford OX3 9DU, United Kingdom; helen.barron@merton.ox.ac.uk tim.vogels@cncb.ox.ac.uk behrens@fmrib.ox.ac.uk mani.ramaswami@tcd.ie.
- 2
- Medical Research Council Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom.
- 3
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, United Kingdom; helen.barron@merton.ox.ac.uk tim.vogels@cncb.ox.ac.uk behrens@fmrib.ox.ac.uk mani.ramaswami@tcd.ie.
- 4
- The Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
- 5
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland; helen.barron@merton.ox.ac.uk tim.vogels@cncb.ox.ac.uk behrens@fmrib.ox.ac.uk mani.ramaswami@tcd.ie.
- 6
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India.
Abstract
Les systèmes nerveux utilisent des assemblages de cellules excitatrices pour coder et représenter les perceptions sensorielles. De
même, les assemblages de cellules syntaxiquement connectés ou les
"engrammes" sont censés représenter des souvenirs de l'expérience passée. Plusieurs
lignes de preuves récentes indiquent que les systèmes cérébraux créent
et utilisent des répliques inhibitrices de représentations excitatrices
pour des fonctions cognitives importantes. De
telles «engrammes inhibitrices » compatibles peuvent se former à travers
une potentialisation homéostatique de l'inhibition sur des cellules
postsynaptiques qui présentent des niveaux d'excitation accrus. Les
engrammes inhibitrices peuvent réduire les réponses comportementales à
des stimuli familiers, ce qui entraîne une accoutumance comportementale.
De
plus, en empêchant une activation inappropriée des engrammes à mémoire
excitatrice, les engrammes inhibitrices peuvent rendre les mémoires à l'état de repos, stockées sous une forme latente disponible pour une
activation contextuelle. Dans
les réseaux de neurones avec des engrammes excitatrices et inhibitrices
équilibrées, la libération de réponses innées et le rappel des souvenirs
associatifs peuvent se produire par désinhibition ciblée. La compréhension des mécanismes qui régulent la formation et
l'expression des engrammes inhibitrices in vivo peut aider non seulement à
expliquer les caractéristiques clés de la cognition, mais aussi à
fournir un aperçu des traits transdiagnostiques associés à des
affections psychiatriques telles que l'autisme, la schizophrénie et le
syndrome de stress post-traumatique.
Nervous systems use excitatory cell assemblies to encode and represent sensory percepts. Similarly, synaptically connected cell assemblies or "engrams" are thought to represent memories of past experience. Multiple lines of recent evidence indicate that brain systems create and use inhibitory replicas of excitatory representations for important cognitive functions. Such matched "inhibitory engrams" can form through homeostatic potentiation of inhibition onto postsynaptic cells that show increased levels of excitation. Inhibitory engrams can reduce behavioral responses to familiar stimuli, thereby resulting in behavioral habituation. In addition, by preventing inappropriate activation of excitatory memory engrams, inhibitory engrams can make memories quiescent, stored in a latent form that is available for context-relevant activation. In neural networks with balanced excitatory and inhibitory engrams, the release of innate responses and recall of associative memories can occur through focused disinhibition. Understanding mechanisms that regulate the formation and expression of inhibitory engrams in vivo may help not only to explain key features of cognition but also to provide insight into transdiagnostic traits associated with psychiatric conditions such as autism, schizophrenia, and posttraumatic stress disorder.
Nervous systems use excitatory cell assemblies to encode and represent sensory percepts. Similarly, synaptically connected cell assemblies or "engrams" are thought to represent memories of past experience. Multiple lines of recent evidence indicate that brain systems create and use inhibitory replicas of excitatory representations for important cognitive functions. Such matched "inhibitory engrams" can form through homeostatic potentiation of inhibition onto postsynaptic cells that show increased levels of excitation. Inhibitory engrams can reduce behavioral responses to familiar stimuli, thereby resulting in behavioral habituation. In addition, by preventing inappropriate activation of excitatory memory engrams, inhibitory engrams can make memories quiescent, stored in a latent form that is available for context-relevant activation. In neural networks with balanced excitatory and inhibitory engrams, the release of innate responses and recall of associative memories can occur through focused disinhibition. Understanding mechanisms that regulate the formation and expression of inhibitory engrams in vivo may help not only to explain key features of cognition but also to provide insight into transdiagnostic traits associated with psychiatric conditions such as autism, schizophrenia, and posttraumatic stress disorder.
- PMID:2811219
- DOI:1.1073/pnas.1701812114
