Laterodorsal tegmentum interneuron subtypes oppositely regulate olfactory cue-induced innate fear

Area of Science:

• Neuroscience
• Animal Behavior
• Molecular Biology

Background:

• Innate fear is vital for survival, but its underlying neuronal circuits remain poorly understood.
• Conditioned fear pathways are well-studied, contrasting with the limited knowledge of innate fear mechanisms.

Purpose of the Study:

• To elucidate the neural circuitry responsible for innate fear triggered by predator olfactory cues.
• To investigate the roles of the laterodorsal tegmentum (LDT) and lateral habenula (LHb) in innate fear responses.

Main Methods:

• Optogenetic stimulation and inhibition of specific neuronal populations within the LDT.
• Analysis of behavioral responses (freezing, heart rate, corticosterone levels) to predator odor (trimethylthiazoline, TMT).
• Investigating the role of parvalbumin (PV)-positive and somatostatin-positive interneurons in the LDT.

Main Results:

• The laterodorsal tegmentum (LDT) and lateral habenula (LHb) were specifically activated by the predator odorant trimethylthiazoline (TMT).
• Selective optogenetic stimulation of GABAergic neurons in the LDT induced immediate fear-like responses and prolonged anxiety-like behaviors.
• Activation of LHb glutamatergic inputs to LDT interneurons mimicked innate fear responses.

Conclusions:

• The LHb-LDT pathway is critical for processing olfactory cues that elicit innate fear.
• Specific interneurons within the LDT modulate innate fear responses.
• This pathway represents a potential therapeutic target for anxiety disorders.