Parabrachial complex processes dura inputs through a direct trigeminal ganglion-to-parabrachial connection

Abstract

Migraines cause significant disability and contribute heavily to healthcare costs. Irritation of the meninges outermost layer (the dura mater), and trigeminal ganglion activation contribute to migraine initiation. Maladaptive changes in central pain-processing regions are also important in maintaining pain. The parabrachial complex (PB) is a central region that mediates chronic pain. PB receives diverse sensory information, including a direct input from the trigeminal ganglion. We hypothesized that PB processes inputs from the dura. Using in vivo electrophysiology recordings from single units in anesthetized rats we identified 58 neurons in lateral PB that respond reliably and with short latency to electrical dura stimulation. After injecting tracer into PB, anatomical examination reveals retrogradely labeled cell bodies in the trigeminal ganglion. Neuroanatomical tract-tracing revealed a population of neurons in the trigeminal ganglion that innervate the dura and project directly to PB. These findings indicate that PB is strategically placed to process dura inputs, and suggest that it is directly involved in the pathogenesis of migraine headaches.

Anatomy and Physiology of Headache

“…101 While most input to the PBN is likely mediated by SpN neurons, a recent study demonstrated a direct dural afferent projection to the PBN. 102 The PAG is involved in ascending and descending pain modulation and affective responses to pain. It receives ascending input from Vc neurons and descending inputs from subcortical regions including the hypothalamus.…”

“…101 While most input to the PBN is likely mediated by SpN neurons, a recent study demonstrated a direct dural afferent projection to the PBN. 102…”