A cortical circuit for orchestrating oromanual food manipulation

Area of Science:

• Neuroscience
• Motor Control
• Behavioral Science

Background:

• Feeding involves complex hand-mouth coordination, a skill seen in rodents and primates.
• While basic motor actions are controlled by spinal and brainstem circuits, the neocortical role in assembling these into feeding behaviors is not fully understood.

Purpose of the Study:

• To identify and characterize neocortical circuits responsible for coordinating forelimb and orofacial movements during feeding.

Main Methods:

• Systematic optogenetic screening was used to identify neuronal populations in the rostral forelimb-orofacial area (RFO).
• Researchers examined the projection targets and functional roles of pyramidal tract (PT^Fezf2) and intratelencephalic (IT^PlxnD1) neurons within the RFO during feeding behaviors.

Main Results:

• Activation of RFO neurons, specifically PT^Fezf2 or IT^PlxnD1 subtypes, elicited coordinated movements mimicking natural feeding.
• PT^Fezf2 neurons project to subcortical motor centers, while IT^PlxnD1 neurons target cortical and striatal areas involved in oromanual coordination.
• Silencing experiments revealed that PT^Fezf2 neurons are crucial for dexterous hand-mouth movements, whereas IT^PlxnD1 neurons are vital for their temporal coordination during eating.

Conclusions:

• The study defines a cell-type-specific circuit within the RFO that is essential for orchestrating the multi-effector coordination required for natural feeding.
• These findings elucidate the neural basis of complex motor behaviors and provide insights into the hierarchical organization of the motor cortex.