Anterior Cingulate Cortex to Ventral Hippocampus Circuit Mediates Contextual Fear Generalization

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Systems Neuroscience

Background:

• Contextual fear memory can become generalized over time, a process known as fear generalization.
• This overgeneralization is a key symptom in post-traumatic stress disorder (PTSD), but the underlying neural circuits are not fully understood.

Purpose of the Study:

• To investigate the neural circuit mechanisms controlling contextual fear generalization.
• To determine the role of the anterior cingulate cortex (ACC) and ventral hippocampus (vHPC) in fear generalization.

Main Methods:

• Used male mice to study contextual fear memory.
• Employed chemogenetic and photogenetic techniques to manipulate neural activity in the ACC and vHPC.
• Measured neural activity using C-fos expression.
• Investigated the projection pathway from ACC to vHPC.

Main Results:

• Retrieval of contextual fear in a novel context activated ACC and vHPC neurons.
• Silencing ACC or vHPC neurons reduced fear generalization.
• Stimulating ACC or vHPC neurons facilitated fear generalization.
• Silencing projections from ACC to vHPC inhibited fear generalization.

Conclusions:

• A neural circuit comprising projections from the ACC to the vHPC mediates contextual fear generalization.
• This ACC-vHPC circuit is a potential target for therapeutic strategies to prevent or reverse fear generalization in anxiety disorders, including PTSD.