Abstract
Preganglionic axons arising from different levels of the mammalian spinal cord make preferential connexions with different classes of superior cervical ganglion cells (Langley, 1892, 1900; Njå & Purves, 1977a). For example, preganglionic axons from the first thoracic segment (T1) make relatively strong connexions with ganglion cells activating end-organs of the eye; conversely, axons arising from T4 selectively innervate ganglion cells projecting to the ear. In the present work we have asked whether this selectivity reflects the function of the pre- and post-synaptic cells, and aspect of their respective positions, or some other criterion. 1. End-organs with different functions at the same locus (the eye) respond to stimulation of the same ventral roots; end-organs of a single modality (hairs or blood vessels) at different positions, however, tend to be activated by different spinal segments. Thus the segmental innervation of ganglion cells is correlated with the position rather than the function of post-ganglionic targets. 2. The role of target position in ganglion cell innervation was examined directly by recording from neurones sending axons to different destinations. Superior cervical ganglion cells running dorso-medially in a spinal nerve receive, on average, innervation from more caudal segments than cells projecting ventro-laterally. 3. These selective connexions do not depend on intraganglionic cell position: neurones located at different points along the major axes of the superior cervical ganglion receive, on average, the same segmental innervation. In accord with this observation, retrogradely labelled neurones innervating a particular target such as the eye or ear are widely and randomly distributed within a large portion of the ganglion. Thus the importance of post-ganglionic target position in ganglion cell innervation is not simply a reflexion of ganglionic topography. 4. We conclude that one purpose of the selective connexions in the superior cervical ganglion is to bring together preganglionic axons arising from different levels of the spinal cord and ganglion cells whose axons innervate particular regions of the superior cervical territory.
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- GUTH L., BERNSTEIN J. J. Selectivity in the re-establishment of synapses in the superior cervical sympathetic ganglion of the cat. Exp Neurol. 1961 Jul;4:59–69. doi: 10.1016/0014-4886(61)90078-4. [DOI] [PubMed] [Google Scholar]
- Hendry I. A. The effect of the retrograde axonal transport of nerve growth factor on the morphology of adrenergic neurones. Brain Res. 1977 Oct 7;134(2):213–223. doi: 10.1016/0006-8993(77)91068-x. [DOI] [PubMed] [Google Scholar]
- Langley J. N., Anderson H. K. On the Mechanism of the Movements of the Iris. J Physiol. 1892 Oct;13(6):554–597. doi: 10.1113/jphysiol.1892.sp000426. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langley J. N. Note on Regeneration of Prae-Ganglionic Fibres of the Sympathetic. J Physiol. 1895 Jul 18;18(3):280–284. doi: 10.1113/jphysiol.1895.sp000566. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langley J. N. On the Regeneration of Pre-Ganglionic and of Post-Ganglionic Visceral Nerve Fibres. J Physiol. 1897 Nov 20;22(3):215–230. doi: 10.1113/jphysiol.1897.sp000688. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langley J. N., Sherrington C. S. On Pilomotor Nerves. J Physiol. 1891 Aug;12(3):278–291. doi: 10.1113/jphysiol.1891.sp000383. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langley J. N. The Arrangement of the Sympathetic Nervous System, based chiefly on Observations upon Pilo-motor Nerves. J Physiol. 1893 Sep;15(3):176–248.21. doi: 10.1113/jphysiol.1893.sp000470. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MURRAY J. G., THOMPSON J. W. The occurrence and function of collateral sprouting in the sympathetic nervous system of the cat. J Physiol. 1957 Jan 23;135(1):133–162. doi: 10.1113/jphysiol.1957.sp005700. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nja A., Purves D. Re-innervation of guinea-pig superior cervical ganglion cells by preganglionic fibres arising from different levels of the spinal cord. J Physiol. 1977 Nov;272(3):633–651. doi: 10.1113/jphysiol.1977.sp012064. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Njå A., Purves D. Specific innervation of guinea-pig superior cervical ganglion cells by preganglionic fibres arising from different levels of the spinal cord. J Physiol. 1977 Jan;264(2):565–583. doi: 10.1113/jphysiol.1977.sp011683. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Njå A., Purves D. Specificity of initial synaptic contacts made on guinea-pig superior cervical ganglion cells during regeneration of the cervical sympathetic trunk. J Physiol. 1978 Aug;281:45–62. doi: 10.1113/jphysiol.1978.sp012408. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Purves D. Competitive and non-competitive re-innervation of mammalian sympathetic neurones by native and foreign fibres. J Physiol. 1976 Oct;261(2):453–475. doi: 10.1113/jphysiol.1976.sp011568. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Purves D. Functional and structural changes in mammalian sympathetic neurones following interruption of their axons. J Physiol. 1975 Nov;252(2):429–463. doi: 10.1113/jphysiol.1975.sp011151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Purves D., Lichtman J. W. Formation and maintenance of synaptic connections in autonomic ganglia. Physiol Rev. 1978 Oct;58(4):821–862. doi: 10.1152/physrev.1978.58.4.821. [DOI] [PubMed] [Google Scholar]