Progressive long-term synaptic depression at cortical inputs into the amygdala

Area of Science:

• Neuroscience
• Synaptic Plasticity
• Fear Conditioning

Background:

• The lateral amygdala (LA) integrates conditioned (CS) and unconditioned (US) stimuli, forming the basis for fear responses.
• Pavlovian conditioning modulates synaptic plasticity, evidenced by long-term potentiation (LTP) in the amygdala.
• Reliable demonstration of long-term depression (LTD) of excitatory synapses in the LA remains challenging.

Purpose of the Study:

• To investigate and establish a reliable method for inducing long-term depression (LTD) in the lateral amygdala (LA).
• To characterize the properties of LTD in LA pyramidal neurons.

Main Methods:

• Utilized coronal brain slices for patch-clamp recordings in lateral amygdala (LA) pyramidal neurons.
• Established a stable baseline excitatory postsynaptic current (EPSC) at -70 mV.
• Employed a 1 Hz paired-pulse stimulation paradigm at a constant membrane potential to induce and observe LTD.

Main Results:

• A reliable long-term depression (LTD) of excitatory postsynaptic currents (EPSCs) was successfully induced in LA pyramidal neurons.
• Varying stimulation durations (1.5-24 min) at constant intensity resulted in a step-wise LTD with gradually increasing magnitude.

Conclusions:

• The study successfully established a reliable paired-pulse stimulation protocol for inducing LTD in the lateral amygdala (LA).
• This work provides a foundation for further investigation into the mechanisms and functional significance of LTD in fear memory.