Monosynaptic convergence of chorda tympani and glossopharyngeal afferents onto ascending relay neurons in the nucleus of the solitary tract: A high-resolution confocal and correlative electron microscopy approach
Article first published online: 17 JUL 2013
Copyright © 2013 Wiley Periodicals, Inc.
Journal of Comparative Neurology
Volume 521, Issue 13, pages 2907–2926, 1 September 2013
How to Cite
Corson, J. A. and Erisir, A. (2013), Monosynaptic convergence of chorda tympani and glossopharyngeal afferents onto ascending relay neurons in the nucleus of the solitary tract: A high-resolution confocal and correlative electron microscopy approach. J. Comp. Neurol., 521: 2907–2926. doi: 10.1002/cne.23357
- Issue published online: 17 JUL 2013
- Article first published online: 17 JUL 2013
- Accepted manuscript online: 3 MAY 2013 02:40AM EST
- Manuscript Accepted: 25 APR 2013
- Manuscript Revised: 16 APR 2013
- Manuscript Received: 27 AUG 2012
- National Institute of Deafness and Other Communication Disorders . Grant Number: R01DC10183
- primary afferent innervation;
Physiological studies suggest convergence of chorda tympani and glossopharyngeal afferent axons onto single neurons of the rostral nucleus of the solitary tract (rNTS), but anatomical evidence has been elusive. The current study uses high-magnification confocal microscopy to identify putative synaptic contacts from afferent fibers of the two nerves onto individual projection neurons. Imaged tissue is revisualized with electron microscopy, confirming that overlapping fluorescent signals in confocal z-stacks accurately identify appositions between labeled terminal and dendrite pairs. Monte Carlo modeling reveals that the probability of overlapping fluorophores is stochastically unrelated to the density of afferent label, suggesting that convergent innervation in the rNTS is selective rather than opportunistic. Putative synaptic contacts from each nerve are often compartmentalized onto dendrite segments of convergently innervated neurons. These results have important implications for orosensory processing in the rNTS, and the techniques presented here have applications in investigations of neural microcircuitry with an emphasis on innervation patterning. J. Comp. Neurol. 521: 2907–2926, 2013. © 2013 Wiley Periodicals, Inc.