Quantitative analysis of synaptic distribution along thalamocortical axons in adult mouse barrels

The Journal of Comparative Neurology
E L WhiteDmitri L Lev

Abstract

Quantitative data on thalamocortical synapses in adult mouse barrels have been obtained largely by using lesion-nduced degeneration to label thalamic afferents. By the time degenerating axons can be identified with the electron microscope, they have broken up into many separate pieces, making it impossible to assess the distribution of synapses along unbroken lengths of afferent. Here, this deficiency is rectified by examining intact lengths of axon labeled by the injection of biotinylated dextran amine into ipsilateral thalamus. Serial thin section reconstructions were analyzed to determine the numbers of synapses per axon length made with dendritic spines vs. shafts and the locations of synapses with respect to axonal varicosities. Results for seven axonal segments from six mice showed an average of 0.2 synapses/microm; 80% were made with spines and 20% with dendritic shafts. Just over two-thirds of axonal varicosities formed one synapse; most of the remainder formed two and rarely three, whereas 8% formed none. Although most synapses occurred at varicosities (88%), more than 12% were made at cylindrically shaped regions of the reconstructed axonal segments. These results serve as a caveat for the use of light microscopy to q...Continue Reading

References

Jul 28, 1977·Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character·D H Hubel, T N Wiesel
Mar 23, 1979·Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences·J J Sloper, T P Powell
Aug 20, 1976·Brain Research·S LeVay, C D Gilbert
Dec 22, 1992·Proceedings. Biological Sciences·J C AndersonJ C Nelson
Mar 1, 1992·Journal of Neuroscience Methods·C L VeenmanM G Honig
Aug 1, 1990·Journal of Electron Microscopy Technique·H J Ralston
Apr 22, 1987·The Journal of Comparative Neurology·K L Bernardo, T A Woolsey
Oct 12, 1971·Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character·L J Garey, T P Powell
Jan 29, 1970·Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences·E G Jones, T P Powell
Oct 31, 1983·Brain Research·D A Winfield, T P Powell
May 1, 1981·The Journal of Comparative Neurology·E L White, S M Hersch
Jun 1, 1981·The Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society·J C Adams
Apr 1, 1980·The Journal of Comparative Neurology·L M SmithM Colonnier
Jul 1, 1995·Cerebral Cortex·V Mountcastle
Nov 1, 1994·The European Journal of Neuroscience·K HerrmannC J Shatz
Aug 1, 1994·The Journal of Comparative Neurology·B L Schlaggar, D D O'Leary

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Citations

Feb 4, 2009·Cerebral Cortex·Pablo Rubio-GarridoFrancisco Clascá
Jun 11, 2010·Cerebral Cortex·Hanno S MeyerMoritz Helmstaedter
Jul 16, 2010·Journal of Neurophysiology·Brian HalabiskyDavid A Prince
Sep 12, 2008·The Journal of Neuroscience : the Official Journal of the Society for Neuroscience·Claire E J CheethamGerald T Finnerty
Jul 14, 2010·Current Opinion in Neurobiology·Jerry L Chen, Elly Nedivi
Jan 22, 2008·International Journal of Developmental Neuroscience : the Official Journal of the International Society for Developmental Neuroscience·Ivett Medina-AguirreGabriel Manjarrez-Gutiérrez
Sep 12, 2006·Current Opinion in Neurobiology·Kevin L Briggman, Winfried Denk
Sep 9, 2015·Frontiers in Neuroanatomy·Javier DeFelipe
Oct 6, 2009·The Neuroscientist : a Review Journal Bringing Neurobiology, Neurology and Psychiatry·Samuel J Barnes, Gerald T Finnerty
Apr 23, 2005·The Journal of Comparative Neurology·Jennifer L Freese, David G Amaral
Jun 24, 2017·Nature Communications·Kelly A TennantCraig E Brown
Dec 29, 2020·The European Journal of Neuroscience·Vandana SampathkumarNarayanan Kasthuri

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