Learning how to avoid danger and pursue reward depends on negative emotions motivating aversive learning and positive emotions
motivating appetitive learning. The amygdala is a key component of the brain emotional system; however, an understanding of how
various emotions are differentially processed in the amygdala has yet to be achieved.Wereport that matrix metalloproteinase-9 (MMP-9,
extracellularly operating enzyme) in the central nucleus of the amygdala (CeA) is crucial for appetitive, but ...
Learning how to avoid danger and pursue reward depends on negative emotions motivating aversive learning and positive emotions
motivating appetitive learning. The amygdala is a key component of the brain emotional system; however, an understanding of how
various emotions are differentially processed in the amygdala has yet to be achieved.Wereport that matrix metalloproteinase-9 (MMP-9,
extracellularly operating enzyme) in the central nucleus of the amygdala (CeA) is crucial for appetitive, but not for aversive, learning in
mice. The knock-out of MMP-9 impairs appetitively motivated conditioning, but not an aversive one. MMP-9 is present at the excitatory
synapses in the CeA with its activity greatly enhanced after the appetitive training. Finally, blocking extracellular MMP-9 activity with its
inhibitor TIMP-1 provides evidence that local MMP-9 activity in the CeA is crucial for the appetitive, but not for aversive, learning.
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