Encoding of danger by parabrachial CGRP neurons

Area of Science:

• Neuroscience
• Behavioral Biology
• Sensory Physiology

Background:

• Survival necessitates appropriate responses to diverse threats.
• Calcitonin gene-related peptide (CGRP) neurons in the parabrachial nucleus (PBN) are implicated in processing satiation and fear behaviors.
• The precise encoding mechanisms of these distinct processes by CGRP^PBN neurons remain incompletely understood.

Purpose of the Study:

• To investigate the role of CGRP^PBN neurons in encoding sensory signals related to threats and feeding behaviors.
• To determine how CGRP^PBN neurons contribute to adaptive behavioral states.

Main Methods:

• In vivo calcium imaging of individual CGRP^PBN neurons in mice.
• Recording neuronal activity in response to noxious cutaneous and visceral stimuli.
• Assessing neuronal responses during feeding, satiation, and in response to novel food cues and conditioned fear stimuli.
• Evaluating the behavioral effects of CGRP^PBN neuron silencing on food neophobia and conditioned fear.

Main Results:

• Most CGRP^PBN neurons are activated by noxious stimuli (cutaneous and visceral).
• These neurons are inhibited during feeding but activated during satiation, suggesting a role in preventing overeating.
• CGRP^PBN neurons respond to novel food consumption and auditory cues associated with negative experiences (footshocks).
• Silencing CGRP^PBN neurons reduces food neophobia and conditioned fear responses.

Conclusions:

• CGRP^PBN neurons are crucial for transducing primary sensory danger signals.
• These neurons play a significant role in promoting affective-behavioral states that mitigate harm from potential threats.
• CGRP^PBN neurons integrate sensory information to orchestrate adaptive survival behaviors.