How learning in the present shapes future learning / La façon dont le cerveau apprend aujourd'hui influence l'apprentissage de demain

OUTREACH ARTICLE / ARTICLE DE VULGARISATION
(see related scientific article below / voir l'article scientifique correspondant plus bas)

Science Daily
Click here to access outreach article / Cliquer ici pour accéder à cet article de vulgarisation

How learning in the present shapes future learning - Prefrontal cortex shapes memory formation by modulating hippocampal encoding

Summary / Résumé

Neurons in the prefrontal cortex “teach” neurons in the hippocampus to “learn” rules that distinguish memory-based predictions in otherwise identical situations, suggesting that learning in the present helps guide learning in the future, according to research.

Des neurones dans le cortex préfrontal "enseignent" aux neurones de l'hippocampe à "apprendre" des règles permettant de faire des prédictions distinctes basées sur différents éléments en mémoire, dans des situations autrement identiques. Selon cette recherche, cela suggère que l'apprentissage d'aujourd'hui aide à guider les apprentissages subséquents. 


SCIENTIFIC ARTICLE / ARTICLE SCIENTIFIQUE

Guise, K. G., & Shapiro, M. L. (2017). Medial Prefrontal Cortex Reduces Memory Interference by Modifying Hippocampal Encoding. Neuron, 94(1), 183-192.

DOI: 10.1016/j.neuron.2017.03.011

HIGHLIGHTS / FAITS SAILLANTS

  • mPFC differentiates memories during encoding to prevent interference /
    Le cortex préfrontal médial (CPFm) différencie les éléments en mémoire pendant leur encodage pour prévenir une potentielle interférence entre eux.
  • Population activity in both mPFC and CA1 predicts choices in single trials /
    L'activité neuronale dans le CPFm et la région CA1 de l'hippocampe prédit les choix dans des essais uniques.
  • mPFC influence on CA1 activity predicted subsequent learning speed /
    L'influence du CPFm sur l'activité neuronale de la région CA1 prédit la vitesse des apprentissages subséquents.
  • mPFC inactivation reduced pattern separation in CA1 representations /
    L'inactivation du CPFm diminue la différenciation des patrons dans les représentations neuronales de la région CA1.

ABSTRACT

The prefrontal cortex (PFC) is crucial for accurate memory performance when prior knowledge interferes with new learning, but the mechanisms that minimize proactive interference are unknown. To investigate these, we assessed the influence of medial PFC (mPFC) activity on spatial learning and hippocampal coding in a plus maze task that requires both structures. mPFC inactivation did not impair spatial learning or retrieval per se, but impaired the ability to follow changing spatial rules. mPFC and CA1 ensembles recorded simultaneously predicted goal choices and tracked changing rules; inactivating mPFC attenuated CA1 prospective coding. mPFC activity modified CA1 codes during learning, which in turn predicted how quickly rats adapted to subsequent rule changes. The results suggest that task rules signaled by the mPFC become incorporated into hippocampal representations and support prospective coding. By this mechanism, mPFC activity prevents interference by “teaching” the hippocampus to retrieve distinct representations of similar circumstances.

Keywords
hippocampus; CA1; learning; memory; neuronal representation; prefrontal cortex; proactive interference; recall; retrieval