Point: 11. Nucleus and Tractus Solitarius
Nucleus receives input from the viscera and taste buds
Caudal portion of nucleus solitarius receives input from
viscera (cell bodies in the inferior ganglion X) and from
the carotid sinus (baroreceptors; cells in the inferior
ganglion IX). Central processes travel in caudal fasciculus
solitarius and synapse in caudal nucleus solitarius. Cells
in caudal nucleus solitarius project to the dorsal motor
nucleus X and other parts of the brainstem and spinal cord
involved in visceral reflexes (lateral cell column in spinal
cord). Rostral part solitary complex receives TASTE input
from central processes of cells in the geniculate ganglion
VII (taste buds on ant. 2/3 tongue), inferior ganglion IX
(taste buds on post. 1/3 of tongue) and inferior ganglion X
(scattered taste buds on the epiglottis). Axons arising from
cells in the rostral nucleus solitarius comprise the
solitariothalamic tract (S.T.T.). The S.T.T. is an UNCROSSED
pathway that terminates in the V.P.M. of the thalamus. Cells
in the V.P.M. project to somatosensory cortex (areas 3,1,2).
Lesion of rostral portion of nucleus and tractus solitarius
is the most important. Such lesions result in the loss of
taste from the IPSI. one half of the tongue. Lesion of the
S.T.T. also results in the loss of taste from the IPSI.
one-half of the tongue.
NO PROBLEMS WITH PAIN AND TEMPERATURE FROM THE TONGUE.