Bc. Steinbacher et Bj. Yates, PROCESSING OF VESTIBULAR AND OTHER INPUTS BY THE CAUDAL VENTROLATERALMEDULLARY RETICULAR-FORMATION, American journal of physiology. Regulatory, integrative and comparative physiology, 40(4), 1996, pp. 1070-1077
Lesions of the lateral medullary reticular formation caudal to the obe
x abolish vestibulosympathetic and somatosympathetic responses; this a
rea also contains neurons that mediate baroreceptor reflexes. Recordin
gs were made from neurons in the caudal medullary reticular formation
of cats that were decerebrate or anesthetized using alpha-chloralose-u
rethan to determine whether common neurons responded to electrical sti
mulation of vestibular and hindlimb afferents and had cardiac-related
(i.e., baroreceptor) inputs. Many neurons in the ventrolateral portion
of the caudal reticular formation received labyrinthine inputs, and t
hey were interspersed with neurons that received baroreceptor signals.
However virtually none of the units received convergent baroreceptor
and vestibular inputs, suggesting that separate pathways from the caud
al ventrolateral medulla mediate baroreceptor and vestibulosympathetic
reflexes. Furthermore, the neurons that received labyrinthine signals
could not be antidromically activated from electrodes inserted into t
he rostral ventrolateral medulla, which is known to mediate vestibulos
ympathetic responses; thus an indirect pathway must convey vestibular
inputs from the caudal to rostral medullary reticular formation. Over
75% of both neurons with baroreceptor inputs and cells with vestibular
signals responded to sciatic nerve stimulation, suggesting that more
than one pathway from the caudal medulla may mediate somatosympathetic
responses.