Authors: |
*L. DIAZ-MATAIX1, E. SANTINI1, E. C. SARRO2,3,5,6, R. E. PERRY2,4,6,7, L. TALLOT8, J. E. LEDOUX1,2, E. KLANN1, V. DOYERE8, R. M. SULLIVAN2,3,6,7;
1Ctr. for Neural Sci., New York Univ., NEW YORK, NY; 2Emotional Brain Inst., Nathan Kline Inst., Orangeburg, NY; 3Child and Adolescent Psychiatry,, 4Child and Adolescent Psychiatry, New York Univ. Sch. of Med., New York, NY; 5Neurosci. and Physiol., NYU Sackler Inst. for Grad. Biomed, New York, NY; 6NYU Child Study Ctr., NYU Langone Med. Ctr., New York, NY; 7Neurosci. and Physiol., NYU Sackler Inst. for Grad. Biomed. Sci., New York, NY; 8Ctr. of Neurosciences Paris-Sud (CNPS), Univ. Paris XI/CNRS, Orsay, France |
Abstract: |
In rat pups, odor-shock conditioning induces odor preference from birth to post-natal day 9 (PN9), being critical to develop mother-pup attachment and therefore ensure survival. After this age, odor-shock conditioning results in odor aversion. However it is not known whether animals at these ages are able to consolidate odor-shock memories. In adults, mTOR and ERK signaling pathways regulate protein synthesis and the synaptic plastic changes occurring in the amygdala in order to consolidate threat memories. The objective of this work is to study if odor aversion learning following odor-shock conditioning is accompanied by age-dependent alterations in mTOR and/or ERK signaling pathways. Five different groups of animals (PN7-9; PN11-13; PN18-20; PN24-26; adults) were odor conditioned by pairing peppermint odor with a mild hind limb shock. For the behavioral experiments memory was tested 24 hours after conditioning. For the biochemistry experiments animals were sacrificed 15 minutes after the last conditioning trial and the brains were rapidly frozen for later dissection of the amygdala. As expected, animals aged PN11-13 were the youngest to display avoidance of conditioned odor when memory was tested 24 hours after learning. In line with the behavioral results, conditioning-induced phosphorylation in the mTOR and ERK pathways in the amygdala increased with the age of the animals. The results show that odor-shock memory consolidation occurs in parallel with changes in the mTOR and ERK pathways that are critical for plasticity in the amygdala.
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