By the term sympathetic nervous system is usually meant that extensive and diffuse group of outlying neurons which are connected through white rami communicantes with the thoracic and lumbar regions of the spinal cord. Only occasionally is the expression used to include structures more central than the cell bodies of the connector or preganglionic neurons which, as Gaskell1 and others have shown, lie in the lateral horns of the thoracic and lumbar segments of the cord. It has long been recognized that the physiologic activity of these peripheral motor neurons is entirely under the control of the central nervous system, and there is available evidence for the existence of what appear to be fairly definite central mechanisms which are concerned in the discharge of nerve impulses over preganglionic sympathetic neurons. Thus one may speak of a central representation of the sympathetic.
From the earliest times, the necessity for some
BARD P. THE CENTRAL REPRESENTATION OF THE SYMPATHETIC SYSTEMAS INDICATED BY CERTAIN PHYSIOLOGIC OBSERVATIONS. Arch NeurPsych. 1929;22(2):230-246. doi:10.1001/archneurpsyc.1929.02220020046002