Reward disrupts reactivated human skill memory

Abstract

Accumulating evidence across species and memory domains shows that when an existing memory is reactivated, it becomes susceptible to modifications. However, the potential role of reward signals in these mechanisms underlying human memory dynamics is unknown. Leaning on a wealth of findings on the role of reward in reinforcing memory, we tested the impact of reinforcing a skill memory trace with monetary reward following memory reactivation, on strengthening of the memory trace. Reinforcing reactivated memories did not strengthen the memory, but rather led to disruption of the memory trace, breaking down the link between memory reactivation and subsequent memory strength. Statistical modeling further revealed a strong mediating role for memory reactivation in linking between memory encoding and subsequent memory strength only when the memory was replayed without reinforcement. We suggest that, rather than reinforcing the existing memory trace, reward creates a competing memory trace, impairing expression of the original reward-free memory. This mechanism sheds light on the processes underlying skill acquisition, having wide translational implications.

Consolidation and reconsolidation share behavioural and neurochemical mechanisms

“…However, a number of studies have suggested that consolidation does not make memory traces permanently stable. Results of these studies support the theory that retrieval of previously consolidated memory, termed reactivation, renders the memory traces labile again and subject to disruption by new learning unless they go through a further consolidation process, termed reconsolidation 3, 4, 5, 6, 7, 8 . However, it remains controversial whether reactivation and reconsolidation occur at a human behavior level 9, 10, 11 and whether consolidation and reconsolidation have common mechanisms 12, 13 .…”

Sleeping on the motor engram: The multifaceted nature of sleep-related motor memory consolidation

“…Although considerable progress has been made in this research area [e.g., (Bottary et al, 2016;Desrochers et al, 2016;Fogel et al, 2014;Sonni and Spencer, 2015;Wilhelm et al, 2013], additional research is still necessary to further elucidate lifespan changes in the role of sleep on motor memory consolidation. Third, there has been increased interest recently in memory consolidation processes following the reactivation or retrieval of a previously acquired motor memory trace, a process often referred to as reconsolidation (Censor et al, 2016(Censor et al, , 2014Dayan et al, 2016;de Beukelaar et al, 2016de Beukelaar et al, , 2014Hardwicke et al, 2016;Sandrini et al, 2015;Wymbs et al, 2016). The role of post--reactivation sleep on reconsolidation is still poorly understood and necessitates further investigation, as such reactivations are common when learning a motor skill over multiple days / training sessions.…”

Effects of tDCS on motor learning and memory formation: A consensus and critical position paper

“…Each time a given skill is executed, retrieval of these previously consolidated motor memories may initiate a cascade of plasticity mechanisms that enable their composition to be modified in order to maintain skill performance optimization over the long term (Censor, Buch, Nader, & Cohen, 2015;Censor, Dayan, & Cohen, 2014;Censor, Dimyan, & Cohen, 2010;Censor, Horovitz, & Cohen, 2014;Dayan, Laor-Maayany, & Censor, 2016;Wymbs et al, 2016). It has been reported that existing motor memories can be modified through reconsolidation, which may repeat as needed across the lifespan (Censor, Horovitz, et al, 2014;Sandrini, Censor, Mishoe, & Cohen, 2013;Wymbs et al, 2016).…”