Input from the medial geniculate nucleus modulates amygdala encoding of fear memory discrimination. Learn Mem 2017 Sep;24(9):414-421
Date
08/18/2017Pubmed ID
28814467Pubmed Central ID
PMC5580525DOI
10.1101/lm.044131.116Scopus ID
2-s2.0-85027542844 (requires institutional sign-in at Scopus site) 26 CitationsAbstract
Generalization of fear can involve abnormal responding to cues that signal safety and is common in people diagnosed with post-traumatic stress disorder. Differential auditory fear conditioning can be used as a tool to measure changes in fear discrimination and generalization. Most prior work in this area has focused on elevated amygdala activity as a critical component underlying generalization. The amygdala receives input from auditory cortex as well as the medial geniculate nucleus (MgN) of the thalamus, and these synapses undergo plastic changes in response to fear conditioning and are major contributors to the formation of memory related to both safe and threatening cues. The requirement for MgN protein synthesis during auditory discrimination and generalization, as well as the role of MgN plasticity in amygdala encoding of discrimination or generalization, have not been directly tested. GluR1 and GluR2 containing AMPA receptors are found at synapses throughout the amygdala and their expression is persistently up-regulated after learning. Some of these receptors are postsynaptic to terminals from MgN neurons. We found that protein synthesis-dependent plasticity in MgN is necessary for elevated freezing to both aversive and safe auditory cues, and that this is accompanied by changes in the expressions of AMPA receptor and synaptic scaffolding proteins (e.g., SHANK) at amygdala synapses. This work contributes to understanding the neural mechanisms underlying increased fear to safety signals after stress.
Author List
Ferrara NC, Cullen PK, Pullins SP, Rotondo EK, Helmstetter FJAuthor
Fred Helmstetter PhD Professor in the Psychology / Neuroscience department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
Acoustic StimulationAmygdala
Analysis of Variance
Animals
Anisomycin
Conditioning, Classical
Disks Large Homolog 4 Protein
Fear
Geniculate Bodies
Male
Memory
Nerve Tissue Proteins
Neural Pathways
Protein Synthesis Inhibitors
Rats
Rats, Long-Evans
Receptors, AMPA
Synaptic Membranes
