Monthly Archives: November 2018

Guérir d’un coup de ciseaux, vraiment ?

Les modifications du génome font beaucoup parler d’elles dans les médias, surtout depuis l’arrivée en 2012 d’une nouvelle famille de « ciseaux génétiques », efficaces et bon marché : les « Crispr ». Mais que peut-on réellement faire avec ces ciseaux ?

Thursday15 November 2018

Sorry, this entry is only available in French. À ce jour, la synthèse de presse de l’Inserm est réalisée à partir de la lecture de l’ensemble de la presse quotidienne nationale et régionale, de la plupart des hebdomadaires et mensuels grand public et de la presse spécialisée, ainsi que des retombées radio-télévision. Une « synthèse de […]

A new pathway for modulating anti-tumoral immune response

Researchers from Inserm, CNRS, Paris-Sud University, Gustave Roussy, and Institut Curie have identified a new agent in regulating PD-L1 gene expression: the eIF4F complex, which plays a role in controlling protein synthesis.

5 millions supplémentaires pour la recherche sur les cancers pédiatriques

5 millions supplémentaires pour la recherche sur les cancers pédiatriques

Wednesday 14 November 2018

Sorry, this entry is only available in French. À ce jour, la synthèse de presse de l’Inserm est réalisée à partir de la lecture de l’ensemble de la presse quotidienne nationale et régionale, de la plupart des hebdomadaires et mensuels grand public et de la presse spécialisée, ainsi que des retombées radio-télévision. Une « synthèse de […]

Mercredi 14 novembre : journée mondiale du diabète

Le diabète est une maladie causée par un excès permanent de sucre dans le sang qu’on appelle hyperglycémie.

Autism Spectrum Disorder: a new brain imaging study appears to challenge the prevailing theoretical model.

As part of the InFoR-Autism* scientific program, supported by Institut Roche, an MRI neuroimaging study investigated the links between local anatomical connectivity and social cognition in individuals with autism spectrum disorder (ASD).

Tuesday 13 November 2018

Sorry, this entry is only available in French. À ce jour, la synthèse de presse de l’Inserm est réalisée à partir de la lecture de l’ensemble de la presse quotidienne nationale et régionale, de la plupart des hebdomadaires et mensuels grand public et de la presse spécialisée, ainsi que des retombées radio-télévision. Une « synthèse de […]

“Nested sequences”: an indispensable mechanism for forming memories

A research team from CNRS, Université PSL, the Collège de France and Inserm has just lifted part of the veil surrounding brain activity during sleep. Though we know that some neurons are reactivated then to consolidate our memories, we did not know how these cells could “remember” which order to turn on in. The researchers have discovered that reactivating neurons during sleep relies on activation that occurs during the day: “nested” theta sequences. These results were published on November 9, 2018 in Science.
Repetition is the best method for memorization, for neurons themselves. This is the principle behind what neurobiologists call sequence reactivations: during sleep, neurons in the hippocampus related to a task activate very quickly in turn in a precise order, which consolidates the memory of this task. Sequence reactivations are fundamental for long-term memorization and for exchanges between the hippocampus and the rest of the brain. These are only present at rest so they appear after initial neuron activity, which implies that they “memorize” the order they should turn on in. But by which mechanism?
A team of researchers from the Centre interdisciplinaire de recherche en biologie (CNRS/Inserm/Collège de France)1 has answered this question by studying activity sequences in rats’ place cells. These are hippocampal neurons that turn on by following the animal’s position in the environment when it moves. First slowly, while it moves, then very quickly during reactivations of sequences during sleep. But neurobiologists know another type of sequence, called theta sequences, which quickly repeat the activation of the same place cells when the animal moves, in parallel with slow sequences. These theta sequences are therefore called “nested”.
Which of these sequences, slow or nested, is necessary for the appearance of sequence reactivations, and therefore causes the consolidation of memories during sleep? Using an ingenious system, the researchers discovered what deactivates nested sequences, without affecting slow sequences: the animals are transported on an electric train, in a car with a treadmill (see image). When the treadmill is stopped, the nested sequences disappear; they return when the treadmill starts again.
The researchers then observed that after several circuits in the train with the treadmill stopped, place cells in the rats’ hippocampi did not reactivate during sleep in the same order as when awake. On the contrary, after one train circuit with the treadmill on, the sequence reactivations are indeed present. So it is these nested theta sequences during movement that are indispensable for the consolidation of memory during sleep.
The researchers are continuing their work, looking now at the integration of non-spatial information such as objects or textures in nested sequences, and their reactivation during sleep.

1. Associated member of the Université PSL, since 2009 the Collège de France has been conducting a voluntaristic policy for welcoming independent teams that benefit from pooled technical or scientific services and an exceptional multidisciplinary environment. Twenty-two teams are currently housed in the Centre interdisciplinaire de recherche en biologie and in the Instituts de chimie et de physique du Collège de France. Supported by the CNRS in particular, this is available to both French and foreign researchers. It contributes to making Paris a major player as an attractive place for research.

Point d’étape du programme 13 Novembre : la recherche toujours mobilisée

A travers le recueil et l’analyse de témoignages de 1000 personnes volontaires pendant dix ans, le programme 13 Novembre du CNRS et de l’Inserm codirigé par l’historien Denis Peschanski et le neuropsychologue Francis Eustache, vise à étudier la construction et l’évolution de la mémoire après les attentats du 13 novembre 2015, ainsi que l’articulation entre mémoire individuelle et mémoire collective. Les chercheurs tentent de mieux comprendre l’impact des chocs traumatiques sur la mémoire et d’identifier des marqueurs cérébraux associés à la résilience suite à un traumatisme.

fermer
fermer
RSS Youtube