Identification of hippocampus-dependent and hippocampus independent memory components in step-down inhibitory avoidance tasks.
The aim of this study was to determine if the memory of the association between a step-down response and a foot-shock can be dissociated from the memory of the context in which the shocking experience occurred. To test this, two versions of the step-down inhibitory avoidance task were used: a standard version, in which animals were given one trial with a weak exposure to the context and a new version, in which animals were given a stronger exposure to the context. A retention test was performed with the platform placed either in the same conditioning chamber as during the acquisition phase or in a new context. Our results demonstrate that the step-down inhibitory avoidance can actually be solved without a functional hippocampus. Specifically, the results show that hippocampus-lesioned mice and sham controls can express similar level of memory performance but use two different strategies which were distinguished by assessing retention in a new context. Hippocampus-lesioned mice and mice injected with forskolin (adenylyl cyclase activator) 3h after acquisition use a memory strategy which is independent of the context of acquisition. In addition, our results confirm that the cAMP signaling pathway is a key step in memory consolidation processing.
Université Bordeaux 1, Centre de Neurosciences Intégratives et Cognitives, Talence, France. martel@dls.rutgers.edu
Guillaume
G
Martel
Robert
R
Jaffard
Jean-Louis
JL
Guillou
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D004597:Electroshock; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007051:Ibotenic Acid / Q000633:toxicity; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
D005576:Colforsin; D007051:Ibotenic Acid