Morphological characterization of slow and fast pyramidal tract cells in the cat

In adult cats the morphology of slow and fast pyramidal tract (Pt) neurons was studied following intracellular HRP injections and Golgi impregnation. Both types of neurons are pyramidal cells and their soma are all located in the fifth layer of the motor area. As a rule, fast Pt neurons have large somata and their basal and apical dendrites occupy a larger territory in the tangential plane. In layer I, terminal apical dendrites of fast Pt neurons are smooth and divide poorly while those of slow Pt neurons bear a moderate amount of spines and branch profusely. Midway between the pia and layer V, in the third layer, the apical shafts of both types of Pt cells run upward with little branching. These shafts are more numerous in fast Pt cells (7 to 16) and they are almost devoid of spines. Those of slow Pt cells in layer III number between 5 and 9 and are densely covered with spines. Oblique and horizontal branches of slow and fast Pt neurons extend in layer V and some of them invade the lower part of layer III. It is suggested that this zone corresponds to a true fourth layer in the motor area. In both types of cells oblique and lateral branches bear numerous spines. Within the basal dendritic territory of Pt cells, one has to distinguish two dendritic systems: a short and a long one. The former spreads downward obliquely and appears to remain within layer V. The latter is made up of long descending vertical (antiapical) and oblique dendrites (tap root). While both types of cells may have long antiapical dendrites that run down radially to the lower part of layer VI, tap root dendrites which expand laterally below the cell body for considerable distances are a distinctive feature of fast Pt neurons. Though basal dendrites of all Pt cells bear spines, their number, distribution and shape are very variable in fast Pt cells.

[1]  M. Descheˆnes,et al.  A comparative study of ventrolateral and recurrent excitatory postsynaptic potentials in large pyramidal tract cells in the cat , 1979, Brain Research.

[2]  M. Mesulam,et al.  The blue reaction product in horseradish peroxidase neurohistochemistry: incubation parameters and visibility. , 1976, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[3]  E. Evarts.  RELATION OF DISCHARGE FREQUENCY TO CONDUCTION VELOCITY IN PYRAMIDAL TRACT NEURONS. , 1965, Journal of neurophysiology.

[4]  E. Jankowska,et al.  Intracellular application of horseradish peroxidase and its light and electron microscopical appearance in spinocervical tract cells , 1976, Brain Research.

[5]  H. Jasper,et al.  RECURRENT COLLATERAL INHIBITION IN PYRAMIDAL TRACT NEURONS. , 1964, Journal of neurophysiology.

[6]  E. G. Jones,et al.  Varieties and distribution of non‐pyramidal cells in the somatic sensory cortex of the squirrel monkey , 1975, The Journal of comparative neurology.

[7]  J. D. Coulter,et al.  Organization of corticospinal neurons in the cat , 1978, Brain Research.

[8]  A. Peters,et al.  Some aspects of the morphology of Betz cells in the cerebral cortex of the cat. , 1972, Brain research.

[9]  H. Naito,et al.  Transcallosal excitatory postsynaptic potentials of fast and slow pyramidal tract cells in cat sensorimotor cortex. , 1970, Brain research.

[10]  D. Humphrey,et al.  Properties of pyramidal tract neuron system within a functionally defined subregion of primate motor cortex. , 1978, Journal of neurophysiology.

[11]  K. Takahashi,et al.  Slow and fast groups of pyramidal tract cells and their respective membrane properties. , 1965, Journal of neurophysiology.

[12]  C. A. Fox,et al.  A quantitative study of the Purkinje cell dendritic branchlets and their relationship to afferent fibres. , 1957, Journal of anatomy.

[13]  M. Mesulam,et al.  THE JOURNAL OF HISTOCHEMISTRY AND CYTOCHEMISTRY , 2005 .

[14]  M. Karnovsky,et al.  GLOMERULAR PERMEABILITY , 1966, The Journal of experimental medicine.

[15]  E. G. Jones,et al.  Lamination and differential distribution of thalamic afferents within the sensory‐motor cortex of the squirrel monkey , 1975, The Journal of comparative neurology.

[16]  A. Scheibel,et al.  Basilar dendrite bundles of giant pyramidal cells. , 1974, Experimental neurology.

[17]  W. D. Thompson,et al.  Characteristics of projections from primary sensory cortex to motorsensory cortex in cats. , 1970, Brain research.

[18]  M. Marín‐Padilla,et al.  Prenatal and early postnatal ontogenesis of the human motor cortex: a golgi study. I. The sequential development of the cortical layers. , 1970, Brain research.

[19]  H. Kuypers,et al.  Pericruciate cortical neurons projecting to brain stem reticular formation, dorsal column nuclei and spinal cord in the cat , 1975, Neuroscience Letters.

[20]  P J Snow,et al.  Tracing axons and axon collaterals of spinal neurons using intracellular injection of horseradish peroxidase. , 1976, Science.

[21]  V. Braitenberg,et al.  Morphological observations on the cerebellar cortex , 1958, The Journal of comparative neurology.

[22]  F. S. Musgrave,et al.  CORTICAL INTRACELLULAR POTENTIALS DURING AUGMENTING AND RECRUITING RESPONSES. II. PATTERNS OF SYNAPTIC ACTIVITIES IN PYRAMIDAL AND NONPYRAMIDAL TRACT NEURONS. , 1964, Journal of neurophysiology.

[23]  G Oakson,et al.  Inhibitory processes and interneuronal apparatus in motor cortex during sleep and waking. I. Background firing and responsiveness of pyramidal tract neurons and interneurons. , 1974, Journal of neurophysiology.

[24]  J. Sloper.  An electron microscope study of the termination of afferent connections to the primate motor cortex , 1973, Journal of neurocytology.

[25]  T. Powell,et al.  The intrinsic connections of the cortex of area 4 of the monkey. , 1978, Brain : a journal of neurology.

[26]  B. Walmsley,et al.  HRP anatomy of group la afferent contacts on alpha motoneurones , 1979, Brain Research.

[27]  D. Sholl,et al.  Pattern Discrimination and the Visual Cortex , 1953, Nature.

[28]  S Cullheim,et al.  A morphological study of the axons and recurrent axon collaterals of cat sciatic α‐motoneurons after intracellular staining with horseradish peroxidase , 1978, The Journal of comparative neurology.

[29]  J. Adams,et al.  Technical considerations on the use of horseradish peroxidase as a neuronal marker , 1977, Neuroscience.

[30]  H. Jasper,et al.  INTRACELLULAR MICROELECTRODE STUDIES OF ANTIDROMIC RESPONSES IN CORTICAL PYRAMIDAL TRACT NEURONS. , 1964, Journal of neurophysiology.

[31]  M. Colonnier,et al.  An anterograde degeneration study of the tangential spread of axons in cortical areas 17 and 18 of the squirrel monkey (Saimiri Sciureus) , 1978, The Journal of comparative neurology.

[32]  M. Uno,et al.  Recurrent Facilitation in Cat Pyramidal Tract Cells , 1967 .

[33]  G R Stibitz,et al.  Distribution of the apical dendritic spines of the layer V pyramidal cells of the hamster neocortex. , 1968, Brain research.

[34]  Sholl Da.  Dendritic organization in the neurons of the visual and motor cortices of the cat. , 1953 .

[35]  E. Ramón-Moliner,et al.  The histology of the postcruciate gyrus in the cat . II. A statistical analysis of the dendritic distribution , 1961, The Journal of comparative neurology.

[36]  H. Naito,et al.  Precise location of fast and slow pyramidal tract cells in cat sensorimotor cortex. , 1969, Brain research.

[37]  P Sterling,et al.  Synaptic termination of afferents from the ventrolateral nucleus of the thalamus in the cat motor cortex. A light and electron microscope study , 1974, The Journal of comparative neurology.

[38]  H. Asanuma,et al.  Unitary study on evoked activity of callosal neurons and its effect on pyramidal tract cell activity on cats. , 1959, The Japanese journal of physiology.

[39]  J. Jane,et al.  Some observations on axonal degeneration resulting from superficial lesions of the cerebral cortex , 1973, The Journal of comparative neurology.

[40]  T. Powell,et al.  Morphological variations in the dendritic spines of the neocortex. , 1969, Journal of cell science.

[41]  J. L. Conel,et al.  The postnatal development of the human cerebral cortex , 1960 .

[42]  M. Mesulam,et al.  Tetramethyl benzidine for horseradish peroxidase neurohistochemistry: a non-carcinogenic blue reaction product with superior sensitivity for visualizing neural afferents and efferents. , 1978, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.