A brain-to-spinal sensorimotor loop for repetitive self-grooming.

Area of Science:

• Neuroscience
• Behavioral Biology
• Motor Control

Background:

• Self-grooming is a complex behavior with significant biological functions.
• The neural mechanisms coordinating brain and spinal cord for self-grooming are not well understood.

Purpose of the Study:

• To investigate the neural circuit responsible for repetitive orofacial self-grooming.
• To identify the role of specific neurons in the spinal trigeminal nucleus in motor control.

Main Methods:

• Utilized genetic manipulation to target Cerebellin-2 expressing neurons in the spinal trigeminal nucleus (Sp5C).
• Performed neuronal inactivation and activation experiments in mice.
• Traced neural pathways using anatomical and physiological techniques.

Main Results:

• Neurons expressing Cerebellin-2 (Cbln2+) in the Sp5C form a circuit to the cervical spinal cord.
• Inactivating Cbln2+ Sp5C neurons abolished sensory-evoked and stress-induced grooming.
• Activating these neurons induced grooming-like movements.
• A descending pathway from Cbln2+ Sp5C neurons to cervical motor neurons was essential for grooming.

Conclusions:

• A novel brain-to-spinal sensorimotor loop involving Cbln2+ Sp5C neurons controls repetitive orofacial self-grooming.
• This circuit integrates sensory and hypothalamic inputs to drive motor output for grooming behaviors.