Amygdala regulation of immediate-early gene expression in the hippocampus induced by contextual fear conditioning.
The basolateral nuclei of the amygdala (BLA) are thought to modulate memory storage in other brain regions (McGaugh, 2004). We reported that BLA modulates the memory for both an explored context and for contextual fear conditioning. Both of these memories depend on the hippocampus. Here, we examined the hypothesis that the BLA exerts its modulatory effect by regulating the expression of immediate-early genes (IEGs) in the hippocampus. The main findings of these experiments were: (1) Arc activity-regulated cytoskeletal protein (Arc), an immediate-early gene (also termed Arg 3.1) and c-fos mRNA are induced in the hippocampus after a context exposure, or context plus shock experience, but not after an immediate shock; and (2) BLA inactivation with muscimol attenuated the increase in Arc and c-fos mRNA in the hippocampus associated with contextual fear conditioning but did not influence Arc mRNA associated with context exploration. These results support the hypothesis that the amygdala modulates contextual fear memory by regulating expression of IEGs in the hippocampus.
Huff
Nicole C
NC
Department of Psychology, Center for Neuroscience, University of Colorado, Boulder, Colorado 80309, USA.
Frank
Matthew
M
Wright-Hardesty
Karli
K
Sprunger
David
D
Matus-Amat
Patricia
P
Higgins
Emily
E
Rudy
Jerry W
JW
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D003213:Conditioning, Psychological; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics; D005239:Fear / Q000502:physiology*; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; C092069:activity regulated cytoskeletal-associated protein