Two different mirror neuron networks: The sensorimotor (hand) and limbic (face) pathways.

Area of Science:

• Neuroscience
• Primate Neuroanatomy

Background:

• Most mirror neuron (MN) research focuses on hand actions, assuming a shared neuroanatomical network with mouth actions.
• Mouth and hand MNs are found in overlapping sectors of the ventral precentral cortex, reinforcing this assumption.

Purpose of the Study:

• To challenge the assumption of a shared network for hand and mouth mirror neurons.
• To describe the specific connectivity pattern of the mouth mirror neuron sector.

Main Methods:

• Review of existing functional and connectivity studies on mirror neurons in macaque monkeys.
• Analysis of neuroanatomical pathways associated with the mouth MN sector (F5/opercular region).

Main Results:

• Mouth MNs connect to premotor and parietal areas related to face/mouth somatosensory-motor control, and area PrCO for intraoral input.
• Unlike hand MNs, mouth MNs do not receive visual input from parietal regions; input may come from the ventrolateral prefrontal cortex.
• Mouth MNs show strong connections with limbic structures (ACC, insula, OFC, amygdala) involved in emotion and reward processing.

Conclusions:

• The mirror mechanism involves at least two distinct anatomical pathways.
• One pathway supports hand grasping via parietal-premotor circuits.
• A second pathway supports mouth/face control and communication, connecting to limbic areas for emotion and reward processing.