Sleep-dependent reconsolidation after memory destabilization in starlings

Abstract

Reconsolidation theory describes memory formation as an ongoing process that cycles between labile and stable states. Though sleep is critical for the initial consolidation of a memory, there has been little evidence that sleep facilitates reconsolidation. We now demonstrate in two experiments that a sleep-consolidated memory can be destabilized if the memory is reactivated by retrieval. The destabilized memory, which can be impaired if an interference task is encountered after, but not before, the memory is reactivated, is then reconsolidated after sleep. In two additional experiments, we provide evidence suggesting that the learning of the interference task promotes the subsequent sleep-dependent enhancement of the original memory. These results provide novel insight into the complex mechanisms of memory processing, as well as critical evidence supporting the view that long-term memory formation involves a dynamic process of sleep-dependent consolidation, use-dependent destabilization, and sleep-dependent reconsolidation.

Light, Sleep and Performance in Diurnal Birds

“…When auditory memories are retrieved, they return to an unstable state, making them vulnerable to interference. However, Brawn et al [ 113 ] found that during sleep, the destabilized memories were reconsolidated through a cycle of use-dependent destabilization and sleep-dependent reconsolidation. This cycle repeated across several days, while overall song discrimination performance improved.…”

“…Therefore, the interference song seems to have enhanced the memory for the initial song through a sleep-dependent mechanism. The reason for this effect could be that learning the interference song reactivated the memory of the initial song, i.e., if the songs activated similar networks within the brain [ 113 ]. In the wild, such as when a juvenile songbird is learning a specific song, reconsolidation might help stabilize that memory in the presence of interfering songs from other birds [ 114 ].…”

Positive and Neutral Updating Reconsolidate Aversive Episodic Memories via Different Routes

“…This result indicated that sleep promoted memory reconstruction during reconsolidation was more in favor of false memory. It might be because that false memory is relatively more fragile and more reconstructive than true memory with strong bases (Brainerd & Reyna, 2005), which is more likely to profit from sleep (Creery, Oudiette, Antony, & Paller, 2015;Drosopoulos, Schulze, Fischer, & Born, 2007;Oudiette & Paller, 2013) and take longer time to be processed. A study probing into the interaction of sleep and emotional content reported that sleep did not enhance veridical items but fed on false information for emotional materials (McKeon et al, 2012), which was somewhat in line with our results that sleep affects more false rather than true memories.…”

“…With this design, we hypothesized that 1) an impairment of memory for the original negative story on Day-8 only appears in the groups that received both memory reactivation and updating; 2) Since the strength of the updating material differs the degree of impairment for the old memory, i.e., stronger new learning after reactivation leads to better memory updating, we would expect that the group with positive emotion updating should impair the negative memory more than the neutral group. Moreover, 3) a recent study in starlings showed that sleep promoted the reconsolidation of old memory once it has been reactivated, and this effect was notably more substantial when new interferences existed after the reactivation (Brawn, Nusbaum, & Margoliash, 2018). Hence, we hypothesize that after 24-hour interval involving sleep could favor the recovery of the negative memory, especially in the positive group (as a stronger updating manipulation than the neutral updating) with memory reactivation.…”

Sleep is required for odor exposure to consolidate memory and remodel olfactory synapses

“…Male starlings also require sleep to remember a go/no-go task in which they are trained to peck for a reward if they hear a specific song, but not in response to a different one. They cannot learn to update this task if they do not sleep after training (Brawn et al, 2018). Humans also require REM sleep to consolidate memories, especially of complicated tasks, including complex declarative memories (e.g.…”