PMID: 8957530Dec 1, 1996Paper

Recurrent axon collaterals of corticothalamic projection neurons in rat primary somatosensory cortex contribute to excitatory and inhibitory feedback-loops

Anatomy and Embryology
J F StaigerT F Freund

Abstract

Intrinsic circuitry within the primary somatosensory cortex of the rat was examined in a combined light and electron microscope study. Corticothalamic projection neurons were retrogradely labeled by applying Phaseolus vulgaris leucoagglutinin (PHA-L) into the ventro-posteromedial thalamic nucleus (VPM). Most labeled neurons were pyramidal cells of layer VI. Postsynaptic targets of recurrent axon collaterals originating from these neurons were assessed in layers IV and V. Single labeled cells, complete with recurrent collaterals, could be isolated in "barrels" in which no anterograde transport had taken place. These findings were confirmed by first eliminating thalamocortical projections from the VPM with kainic acid and then applying PHA-L into the same nucleus. This procedure led to selective retrograde accumulation of tracer in layer VI pyramidal cells. Reconstructed portions of labeled axonal trees reached layer IV, bringing numerous boutons to layers IV, V and VI. The boutons had characteristic drumstick-like shapes. In order to identify postsynaptic targets, 4 sections of axons stemming from 3 neurons were reembedded and serially sectioned for electron microscopy. The ultrastructure of 72 asymmetric synapses, all belonging...Continue Reading

Citations

Sep 17, 2013·Annales Françaises D'anesthèsie Et De Rèanimation·B JulliacF Sztark
Mar 11, 2003·Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences·Alex M ThomsonOliver T Morris
Feb 24, 2012·The European Journal of Neuroscience·Fabien PichonEgbert Welker
Jun 20, 2003·Journal of Neurophysiology·Michael BeierleinBarry W Connors
Nov 24, 2006·Journal of Neurophysiology·Charles QuairiauxEgbert Welker
Oct 5, 2002·Journal of Neurophysiology·Michael Beierlein, Barry W Connors
May 9, 2001·The Journal of Comparative Neurology·J A Winer, J J Prieto
Aug 20, 2016·Brain Structure & Function·Fuyuki KarubeZoltán F Kisvárday

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