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Trace Fear Conditioning in Mice
Published on: March 20, 2014
Fear conditioning is associated with synaptogenesis in the lateral amygdala
L Dalzell1, S Connor, M Penner
1Department of Psychology, Nipissing University, 100 College Dr., North Bay, ON P1B8L7, Canada.
Synapse (New York, N.Y.)
|October 12, 2010
Summary
This study reveals that fear conditioning in rats leads to an increase in synapses within the lateral amygdala. This structural change in the amygdala may be crucial for acquiring conditioned fear responses.
Area of Science:
- Neuroscience
- Behavioral Neuroscience
- Synaptic Plasticity
Background:
- Fear conditioning involves associating a neutral stimulus (tone) with an aversive stimulus (foot shock), leading to a freeze response.
- The neural circuitry for fear conditioning is known, but synaptic changes in the lateral amygdala remain under-explored.
- The lateral amygdala is a key structure for the acquisition of conditioned fear.
Purpose of the Study:
- To investigate synaptic structural plasticity in the lateral amygdala following fear conditioning.
- To determine if changes in synapse number correlate with the acquisition of conditioned fear.
Main Methods:
- Adult male rats were subjected to fear conditioning (paired tone-shock), unpaired stimuli, or tone-only exposure.
- Electron microscopy and stereological analysis were used to quantify synaptic changes in the lateral amygdala.
- Tissue analysis was performed one day after conditioning and one hour after a fear response probe trial.
Main Results:
- A significant increase in the total number of synapses was observed in the lateral amygdala of conditioned rats compared to control groups.
- This increase in synaptic density suggests structural plasticity occurred in response to fear learning.
Conclusions:
- The acquisition of conditioned fear responses is associated with an increase in synaptic numbers in the lateral amygdala.
- Synaptic structural plasticity in the amygdala may be a fundamental mechanism underlying fear learning.
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