A brainstem circuit for phonation and volume control in mice.

Area of Science:

• Neuroscience
• Animal Communication
• Vocalization Neuroscience

Background:

• Mammalian vocalizations are crucial for communication.
• Phonation, the production of sound via vocal fold vibration, is fundamental to vocalization.
• The precise neural control mechanisms governing phonation remain largely unknown.

Purpose of the Study:

• To identify the specific brain circuits controlling phonation.
• To investigate the role of nucleus retroambiguus (RAm) neurons in vocalization.
• To determine the neural basis for controlling vocal sound volume.

Main Methods:

• Utilized neuroanatomical tracing and in vivo calcium imaging in mice.
• Identified and characterized a subpopulation of neurotensin (Nts)-expressing neurons in the RAm.
• Performed targeted manipulations of RAm Nts neuron activity to assess their necessity and sufficiency for vocalization.

Main Results:

• Discovered a subpopulation of approximately 160 Nts-expressing neurons in the RAm.
• These RAm Nts neurons are activated during both neonatal isolation cries and adult social vocalizations.
• Activating or inhibiting RAm Nts neurons bidirectionally controlled vocalization and sound volume, demonstrating necessity and sufficiency.

Conclusions:

• RAm Nts neurons form a core component of the neural circuit controlling vocalization.
• These neurons play a critical role in generating sound and regulating its volume.
• This finding advances our understanding of the neural underpinnings of vocal communication.