HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ghosh, S Articles by Porter, R Search for Related Content PubMed PubMed Citation Articles by Ghosh, S Articles by Porter, R

Experimental Neurology Unit, John Curtin School of Medical Research, Australian National University, Canberra, A.C.T.

1. Pyramidal neurones in the precentral motor area of the monkey were studied using intracellular techniques. Pyramidal tract neurones (PTNs) were identified by antidromic activation from the cerebral peduncles or medullary pyramids. Orthodromic responses were recorded in PTNs and in other pyramidal neurones when antidromic volleys were set up by stimulation of the peduncles or pyramids. The neurones were then labelled by intracellular ionophoresis of horseradish peroxidase and their morphology examined. All neurones studied were identified as pyramidal cells according to their morphology. 2. Six pyramidal neurones located in lamina V were well stained; they included two fast PTNs and two slow PTNs. The morphology of all pyramidal neurones in this lamina (fast PTNs, slow PTNs and those pyramidal cells that were not antidromically characterized) was essentially similar. A single apical dendrite branched as it ascended and its terminals arborized subpially. Numerous lateral and oblique dendrites branched from the apical dendrites in lamina V and near its border with lamina III: short basal dendrites arborized in the vicinity of the soma in lamina V. Long basal dendrites had a wider field of arborization in lamina V and sometimes extended into lamina VI. 3. Three to five collaterals arose from the axon of lamina V cells in the cortex and arborized in laminae V and VI. Short collateral branches arborized in the vicinity of the soma in the region of the basal and lateral dendrites. Long collateral branches could be traced over long distances (often more than 1 mm). One pyramidal neurone in this lamina (a fast PTN) lacked short collateral branches from the axon. 4. Four pyramidal neurones in lamina III were stained well. The dendritic morphology of all these neurones was similar. Apical dendrites branched as they ascended and terminated subpially. Lateral and basal dendrites formed a column of dendritic branches around the soma. No long basal dendrites were seen. 5. The number and arborization of intracortical collaterals from the axon of lamina III cells varied widely; from three to twelve collaterals arose from the axon. The biggest arbor of collateral branches involved all the cortical laminae and was about 3 mm wide mediolaterally, while the smallest arbor was restricted mainly to lamina III in the vicinity of the soma. One neurone in this lamina also lacked short collateral branches from the axon. 6. Antidromic volleys from the pyramidal tract evoked excitatory responses in fast PTNs, predominantly inhibitory responses in slow PTNs and either excitatory or inhibitory responses in other pyramidal neurones in lamina V.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				M. H. Schieber and G. Rivlis A Spectrum From Pure Post-Spike Effects to Synchrony Effects in Spike-Triggered Averages of Electromyographic Activity During Skilled Finger Movements J Neurophysiol, November 1, 2005; 94(5): 3325 - 3341. [Abstract] [Full Text] [PDF]

				S. K. Esser, S. L. Hill, and G. Tononi Modeling the Effects of Transcranial Magnetic Stimulation on Cortical Circuits J Neurophysiol, July 1, 2005; 94(1): 622 - 639. [Abstract] [Full Text] [PDF]

				C. Capaday The Integrated Nature of Motor Cortical Function Neuroscientist, June 1, 2004; 10(3): 207 - 220. [Abstract] [PDF]

				J. L. Taylor and S. C. Gandevia Noninvasive stimulation of the human corticospinal tract J Appl Physiol, April 1, 2004; 96(4): 1496 - 1503. [Abstract] [Full Text] [PDF]

				H. M. Hamer, H. O. Luders, S. Knake, B. Fritsch, W. H. Oertel, and F. Rosenow Electrophysiology of focal clonic seizures in humans: a study using subdural and depth electrodes Brain, March 1, 2003; 126(3): 547 - 555. [Abstract] [Full Text] [PDF]

				Y. Kang, K. Endo, T. Araki, and T. Kaneko Trans-synaptically Induced Bursts in Regular Spiking Non-pyramidal Cells in Deep Layers of the Cat Motor Cortex Cereb Cortex, January 1, 1999; 9(1): 77 - 89. [Abstract] [Full Text] [PDF]

				P. A. McNulty, V. G. Macefield, J. L. Taylor, and M. Hallett Cortically evoked neural volleys to the human hand are increased during ischaemic block of the forearm J. Physiol., January 1, 2002; 538(1): 279 - 288. [Abstract] [Full Text] [PDF]