scholarly journals The organization of pyramidal and non-pyramidal cell dendrites in relation to thalamic afferent terminations in the monkey somatic sensory cortex

1984 ◽  
Vol 13 (1) ◽  
pp. 183-183
Author(s):  
S. H. C. Hendry ◽  
E. G. Jones
Keyword(s):  
Pyramidal Cell ◽  
Sensory Cortex ◽  
Somatic Sensory Cortex

Synapses on the Axon Hillocks and Initial Segments of Pyramidal Cell Axons in the Cerebral Cortex

1969 ◽  
Vol 5 (2) ◽  
pp. 495-507
Author(s):  
E. G. JONES ◽  
T. P. S. POWELL
Keyword(s):  
Pyramidal Cell ◽  
Synaptic Vesicles ◽  
Initial Segment ◽  
Sensory Cortex ◽  
Axon Terminals ◽  
Dense Bodies ◽  
Inner Surface ◽  
Spine Apparatus ◽  
Membrane Bound ◽  
Somatic Sensory Cortex

The axon hillocks and initial segments of pyramidal cell axons can be clearly recognized in electron micrographs of the somatic sensory cortex. The initial segment is characterized by three features: bundles of neurotubules linked together by electron-dense bands, a layer of dense material attached to the inner surface of the plasma membrane, and small membrane-bound dense bodies. All of these elements and the few ribosomes usually present disappear at the commencement of the myelin sheath. The initial segment of the axon often contains a cluster of cisternae similar to the spine apparatus, and this part of the axon sometimes gives off small branches. Axon terminals end on both the axon hillock and the initial segment, and there is an increase in number on the latter as the distance from the hillock increases. All of these terminals are relatively large, contain a high proportion of small flattened or pleomorphic synaptic vesicles and terminate in symmetrical synaptic contacts. These morphological features suggest that the synapses may be inhibitory in function.

Anatomical analysis of ventrolateral thalamic input to primate motor cortex

1976 ◽  
Vol 39 (5) ◽  
pp. 1020-1031 ◽  
Author(s):  
P. L. Strick
Keyword(s):  
Motor Cortex ◽  
Retrograde Transport ◽  
Sensory Cortex ◽  
Central Sulcus ◽  
Thalamic Neurons ◽  
Thalamic Input ◽  
Continuous Slab ◽  
Ventrolateral Thalamus ◽  
Point To Point ◽  
Somatic Sensory Cortex

1. The origin and topographical organization of input to the arm area of the primate motor cortex from the ventrolateral thalamus were examined using the method of retrograde transport of horseradish peroxidase (HRP). 2. A thin, continuous slab of labeled neurons was found in the ventrolateral thalamus followingmultiple injections of HRP into the arm area of the motor cortex. The slab of labeled neurons was flanked, medially and laterally, by groups of unlabeled neurons. 3. The origin of ventrolateral thalamic input was more extensive than previously thought. Labeled neurons were found from A10.0 to A6.0 and occurred in three ventolateral thalamic subdivisions: ventralis lateralis pars oralis (VLo), ventralis lateralis pars caudalis (VLc), and ventralis posterior lateralis pars oralis (VPLo). For simplicity this region containing labeled neurons has been termed the ventrolateral thalamic (VL) arm area. 4. Injections of HRP into the somatic sensory cortex indicated that the thalamic regions which project to the somatic sensory cortex are separate from the VL arm area. 5. The distribution of labeled neurons following single injections of HRP into different regions of the motor cortex arm area indicated that the VL arm area is topographically organized, particularly its caudal part. Ventral regions of the VL arm area were labeled following HRP injections into motor cortex regions adjacent to the central sulcus where the representation of largely distal musculature is localized. Dorsal regions of the VL arm area were labeled following HRP injections into motor cortex regions more rostral to the central sulcus where the representation of more proximal musculature is localized. 6. A larger region of the VL arm area was labeled following HRP injections adjacent to the central sulcus than following the more rostral motor cortex injections. This suggests that, like the arm area of the motor cortex, more of the VL arm area is allotted to the representation of distal than proximal musculature. 7. Following very small cortical HRP injections, isolated labeled thalamic neurons were diffusely scattered throughout a 3-mm rostrocaudal extent of the VL arm area. In addition, a small focal cluster of labeled thalamic neurons was also seen. The labeled cluster was limited to 0.5 mm rostrocaudally and 300 mum in width. The focal distribution of labeled thalamic neurons suggests that aspects of a point to point organization may exist in the connection between VL and the motor cortex arm area.

Congenital hypothyroidism delays the formation and retards the growth of the mouse primary somatic sensory cortex (S1)

1996 ◽  
Vol 213 (2) ◽  
pp. 132-136 ◽  
Author(s):  
Ali Suha Calikoglu ◽  
Gabriel Gutierrez-Ospina ◽  
A. Joseph D'Ercole
Keyword(s):  
Congenital Hypothyroidism ◽  
Sensory Cortex ◽  
Somatic Sensory Cortex
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