Periaqueductal Gray (PAG)

A gray matter region surrounding the cerebral aqueduct in the midbrain, critically involved in pain modulation, fear responses, and defensive behaviors.

Key Functions:

• Modulates pain perception (descending pain control pathway).
• Mediates fear and defensive behaviors.
• Involved in vocalization and autonomic regulation.

Interacting Systems & Components:

• Midbrain (located within)
• Raphe Nuclei (projects to for pain control)
• Amygdala (receives input from for fear responses)
• Pain Modulation (key center for)
• Autonomic Nervous System (influences)