Gigantocellular reticular nucleus
The gigantocellular reticular nucleus is the medial zone of the reticular formation of the caudal pons and rostral medulla oblongata. It consists of a substantial number of giant neurons, but also contains small and medium sized neurons.
It gives rise to the lateral reticulospinal tract which influences muscle tone of limb and trunk muscles, is involved in coordination of head-eye movements, promotes parasympathetic reduction of heart rate to decrease blood pressure, induces inspiration, and participates in the descending pain-inhibiting pathway.
Anatomy
Afferents
It receives connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular [reticular nucleus].It receives afferent corticoreticular fibers from the premotor cortex and supplementary motor area which modulate the activity of reticulospinal and reticulobulbar efferents.
It receives vestibular, visual, and auditory afferents to mediate head-eye movement coordination.
It receives excitatory enkephalinergic afferents from the periaqueductal gray which influence its descending pain-inhibiting efferents.
Function
Extrapyramidal motor functions
It gives rise to the lateral reticulospinal tract.It is also involved in coordination of head-eye movements.