Fear memories induce a switch in stimulus response and signaling mechanisms for long‐term potentiation in the lateral amygdala
- 1 July 2004
- journal article
- research article
- Published by Wiley in European Journal of Neuroscience
- Vol. 20 (2), 549-556
- https://doi.org/10.1111/j.1460-9568.2004.03517.x
Abstract
Activity-dependent modification of synapses is fundamental for information storage in the brain and underlies behavioral learning. Fear conditioning is a model of emotional memory and anxiety that is expressed as an enduring increase in synaptic strength in the lateral amygdala (LA). Here we analysed synaptic plasticity in the rat cortico-LA pathway during maintenance of fear memory. We show for the first time that the stimulus frequency for synaptic potentiation is switched during maintenance of fear memory, and the underlying signaling mechanisms are altered in the cortico-LA pathway. In slices from fear-conditioned animals, high-frequency stimulation-induced (HFS) long-term potentiation (LTP) was attenuated, whereas low-frequency stimulation (LFS) elicited a long-lasting potentiation. HFS generates robust LTP that is dependent on N-methyl-d-aspartate receptor (NMDAR) and L-type voltage-gated calcium channel (VGCC) activation in control animals, whereas in fear-conditioned animals HFS LTP is NMDAR- and VGCC-independent. LFS-LTP is partially NMDAR-dependent, but VGCCs are necessary for potentiation in fear memory. Collectively, these results show that during maintenance of fear memory the stimulus requirements for amygdala afferents and critical signaling mechanisms for amygdala synaptic potentiation are altered, suggesting that cue-engaged synaptic mechanisms in the amygdala are dramatically affected as a result of emotional learning.Keywords
This publication has 34 references indexed in Scilit:
- Synaptic Plasticity in the AmygdalaAnnals of the New York Academy of Sciences, 2006
- Presynaptic induction of heterosynaptic associative plasticity in the mammalian brainNature, 2003
- Amygdala Modulation of Memory Consolidation: Interaction with Other Brain SystemsNeurobiology of Learning and Memory, 2002
- Involvement of NMDA receptors within the amygdala in short- versus long-term memory for fear conditioning as assessed with fear-potentiated startle.Behavioral Neuroscience, 2000
- Involvement of NMDA receptors within the amygdala in short- versus long-term memory for fear conditioning as assessed with fear-potentiated startle.Behavioral Neuroscience, 2000
- N-methyl-D-aspartate receptors in the basolateral amygdala are required for both acquisition and expression of conditional fear in rats.Behavioral Neuroscience, 1996
- N-methyl-D-aspartate receptors in the basolateral amygdala are required for both acquisition and expression of conditional fear in rats.Behavioral Neuroscience, 1996
- Fear conditioning enhances short-latency auditory responses of lateral amygdala neurons: Parallel recordings in the freely behaving ratNeuron, 1995
- Fear potentiation of the acoustic startle reflex using noises of various spectral frequencies as conditioned stimuliLearning & Behavior, 1992
- Blocking of acquisition but not expression of conditioned fear-potentiated startle by NMDA antagonists in the amygdalaNature, 1990