Active avoidance requires inhibitory signaling in the rodent prelimbic prefrontal cortex

Area of Science:

• Neuroscience
• Behavioral Science
• Anxiety Research

Background:

• Conditioned fear circuits are well-studied in anxiety disorders.
• Neural mechanisms of active avoidance behaviors remain less understood.
• The prelimbic prefrontal cortex (PL) is implicated in anxiety-related behaviors.

Purpose of the Study:

• To investigate the role of the prelimbic prefrontal cortex (PL) in active avoidance.
• To determine the specific neuronal activity (inhibitory vs. excitatory) in the PL associated with avoidance learning.
• To examine the causal relationship between PL neuronal activity and the ability to avoid threats.

Main Methods:

• A tone-signaled, platform-mediated active avoidance task was employed.
• Pharmacological inactivation and optogenetic silencing of the PL were performed.
• Optogenetic stimulation was used to manipulate specific neuronal firing patterns in the rostral PL.

Main Results:

• Pharmacological inactivation of the PL delayed avoidance behavior.
• Optogenetic silencing of PL glutamatergic neurons did not affect avoidance.
• Inhibitory, but not excitatory, neuronal responses in the rostral PL correlated with avoidance training.
• Stimulating rostral PL inhibitory neurons impaired avoidance, suggesting a role in signaling threat avoidability.

Conclusions:

• Inhibitory neural responses in the rostral prelimbic prefrontal cortex (PL) are critical for signaling the avoidability of potential threats.
• These findings highlight the importance of considering specific neuronal firing patterns, particularly inhibitory activity, in the PL for understanding active avoidance.
• The results emphasize the need to design behavioral optogenetic studies that account for naturally occurring neuronal firing responses.