Sentence:  The Mecholyl and noradrenalin tests applied with certain precautions are reliable indicators of this central autonomic balance , but for the sake of correlating autonomic and clinical states , and of studying the effect of certain therapeutic procedures on <WSD>central</WSD> autonomic reactions , additional tests seem to be desirable . 
Meaning of the word marked with <WSD> tags:  in or near a center or constituting a center; the inner area