FUNCTIONAL-ORGANIZATION OF CENTRAL PATHWAYS REGULATING THE CARDIOVASCULAR-SYSTEM

Despite the wealth of information on the anatomy of descending pathways controlling cardiovascular SPNs, there is still a surprising lack of knowledge concerning the precise role of these pathways in cardiovascular regulation. The exception to this is the descending pathway from the RVLM, which has been the most thoroughly studied. Of all the sympathetic premotor nuclei, it is the only one so far identified that is critical for the operation of cardiovascular reflexes and that has been shown to be a major source of tonic excitatory input to cardiovascular SPNs. This does not necessarily mean that other sympathetic premotor nuclei are not important components of the central mechanisms subserving cardiovascular reflexes; rather, the experimental methods so far employed have not yet provided enough information on the functions of these other premotor nuclei to allow their functional roles to be defined.