Anatomically and functionally distinct locus coeruleus efferents mediate opposing effects on anxiety-like behavior

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Stress Response Research

Background:

• The locus coeruleus (LC) is a key brain region involved in stress and anxiety.
• Historically, the LC was viewed as a uniform structure, but recent research suggests neuronal heterogeneity.
• Previous work indicated that a specific stressor activates dorsal LC neurons and increases anxiety-like behaviors in male rats.

Purpose of the Study:

• To investigate the distinct roles of LC neurons projecting to different brain areas in the stress response.
• To understand how specific LC neuronal populations contribute to anxiety-like behavior and exploration.

Main Methods:

• Utilized retrograde tracing to identify LC neuronal projections.
• Employed whole-cell patch clamp electrophysiology to assess neuronal activity.
• Applied chemogenetics to manipulate specific neuronal populations in vivo.

Main Results:

• LC neurons projecting to the central nucleus of the amygdala (CeA) become more excitable post-stress, promoting anxiety.
• LC neurons projecting to the medial prefrontal cortex (mPFC) become less excitable post-stress, potentially promoting exploration.
• Demonstrated distinct physiological responses and behavioral roles for LC neurons based on their projection targets.

Conclusions:

• The locus coeruleus is a heterogeneous nucleus with distinct neuronal populations.
• LC neurons projecting to the CeA and mPFC exhibit opposing roles in anxiety and exploration.
• These findings enhance the understanding of LC's complex role in mediating behavioral responses to stress.