Remembering that things have changed: a review of the cellular mechanisms of memory re-consolidation in the day-old chick.
It has been one of the unshakeable orthodoxies of memory research that memory is initially laid down in a labile form for a short period following the experience and that over time the memory is "fixed" or "consolidated" into the physical structure of the brain. Over the last decade a large body of data has gathered which demonstrates that a "consolidated" memory can be returned to a labile state following retrieval of material from the store, which can then be re-consolidated, incorporating the newly acquired information into the representation of the world. The process of re-consolidation thus provides a sensible means for the crucial process of memory updating to occur. The paper focuses on pharmaco-behavioural experiments undertaken in our laboratories as well as in those of other groups which use the day-old chick as subject and the passive avoidance learning (PAL) task to examine the behavioural and metabolic parameters of re-consolidation. The data indicate that the consolidation and the re-consolidation processes are similar but not identical physiological processes. The re-processing of the memory following a re-consolidation involves each of the glutamatergic, adrenergic and dopaminergic neurotransmitter systems as well as re-activation of protein synthesis associated with the respective traces. In the chick model system, the ability to undertake re-consolidation is transient, and is observed only for a maximum of 24-48 h following the initial training event. Controversy persists as to whether the re-consolidated memory represents a new memory or whether it is a modification of the original memory processing.
Crowe
Simon F
SF
School of Psychological Science, La Trobe University, Bundoora, Melbourne, Victoria 3086, Australia. s.crowe@latrobe.edu.au
Sherry
Joanne M
JM
Hale
Matthew W
MW
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002645:Chickens; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D007858:Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism; D012153:Retention, Psychology
D018698:Glutamic Acid; D009638:Norepinephrine