Nucleus accumbens local circuit for cue-dependent aversive learning.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Molecular Psychiatry

Background:

• Threat detection and response involve encoding environmental cues.
• Aversive events are salient, driving associative learning about threat signals.
• The nucleus accumbens processes salient, aversive information and motivates output via neural plasticity.

Purpose of the Study:

• To elucidate the nucleus accumbens core local circuit's role in fear learning.
• To investigate the involvement of substance P and specific projection neuron plasticity in cue-dependent fear.
• To determine if fear learning and recall depend on distinct projection neuron subtypes.

Main Methods:

• Described a nucleus accumbens core local circuit mechanism.
• Investigated excitatory plasticity's role in learning and recall of aversive cues.
• Assessed the necessity of nucleus accumbens substance P release and plasticity on dopamine 2 receptor-expressing neurons for fear learning.

Main Results:

• Excitatory plasticity in the nucleus accumbens core facilitates learning and recall of discrete aversive cues.
• Nucleus accumbens substance P release and long-term excitatory plasticity on dopamine 2 receptor-expressing projection neurons are essential for cue-dependent fear learning.
• Fear learning and recall are differentially dependent on distinct projection neuron subtypes within the nucleus accumbens.

Conclusions:

• The nucleus accumbens core circuit, through excitatory plasticity, is critical for processing aversive cues.
• Substance P release and plasticity in specific nucleus accumbens neurons are vital for fear learning.
• This study highlights a key role for nucleus accumbens substance P in cue-dependent aversive learning and recall.