Cytoarchitecture and thalamic connectivity of third somatosensory area of cat cerebral cortex

1978 ◽  
Vol 41 (2) ◽  
pp. 268-284 ◽  
Author(s):  
D. G. Tanji ◽  
S. P. Wise ◽  
R. W. Dykes ◽  
E. G. Jones
Keyword(s):  
Cerebral Cortex ◽  
Pyramidal Cells ◽  
Thalamic Nuclei ◽  
Somatosensory Area ◽  
Posterior Group ◽  
Layer V ◽  
Evoked Activity ◽  
To Receive ◽  
The Brain ◽  
Cat Cerebral Cortex

1. The third somatosensory area (SIII) was identified in the cat cerebral cortex by the recording of surface potentials evoked by deflection of a single contralateral mystacial vibrissa. A small amount of tritiated leucine was then injected at the center of the focus of evoked activity and, after a suitable survival period, the brain was prepared for autoradiography. 2. As defined by the presence of an autoradiographic injection, the SIII focus lay in a cytoarchitectonic field characterized in particular by the presence of very large pyramidal cells in layer V and corresponding to area 5a of Hassler and Muhs-Clement (24). 3. The terminal ramifications of corticothalamic cells, as outlined by axoplasmically transported label, formed clustered aggregations in the medial division of the posterior group of thalamic nuclei (Pom) and not in the ventrobasal complex (VB). This part of Pom is known to receive fibers from the spinal cord. 4. Injections of horseradish peroxidase primarily affecting area 5a retrogradely labeled cells in Pom but not in VB. 5. Injections of isotope in the two other foci of vibrissa-evoked activity usually recorded in each brain were invariably found to label a part of area 3b of the first somatosensory area (SI) in the case of the more anterior focus. The second focus sometimes lay in area 2 of SI and sometimes in the second somatosensory area (SII).

The ipsilateral and contralateral connections of the fifth somatosensory area (SV) in the cat cerebral cortex

Neuroreport ◽  
1996 ◽  
Vol 7 (14) ◽  
pp. 2385-2388 ◽  
Author(s):  
Akio Mori ◽  
Tatsu Fuwa ◽  
Akira Kawai ◽  
Toshiaki Yoshimoto ◽  
Yasuo Hiraba ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Somatosensory Area ◽  
Cat Cerebral Cortex

Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat

1983 ◽  
Vol 50 (4) ◽  
pp. 896-909 ◽  
Author(s):  
B. E. Stein ◽  
R. F. Spencer ◽  
S. B. Edwards
Keyword(s):  
Superior Colliculus ◽  
Somatosensory Cortex ◽  
Species Difference ◽  
Pyramidal Cells ◽  
Thalamic Nuclei ◽  
Anterior Ectosylvian Sulcus ◽  
Ventrobasal Complex ◽  
Posterior Group ◽  
Corticothalamic Projection ◽  
Efferent Projections

Substantial corticotectal (and corticothalamic) projections from the cortex of the anterior ectosylvian sulcus (AES) were demonstrated in the cat using the axonal transport methods of autoradiography and horseradish peroxidase. The corticotectal projection arises nearly exclusively from medium-large pyramidal cells in lamina V. One of the densest projecting areas of the AES is the rostral aspect of its superior bank, where a fourth somatotopic representation (SIV) has recently been demonstrated. It terminates in the intermediate and deep laminae of the superior colliculus, where somatic cells are located. The pathway is bilateral but much heavier ipsilaterally than contralaterally. In contrast to the substantial corticotectal projection from SIV and adjacent tissue, there was no unequivocal evidence for a corticotectal projection from traditional somatosensory cortex SI-SIII. This finding, that somatosensory projections to the cat superior colliculus arise from an area outside of SI-SIII, was unexpected on the basis of what is known about visual corticotectal projections. However, it is consistent with the patterns of other cortical projections that terminate in the intermediate and deep laminae of this structure and with the absence of demonstrable corticotectal influences from SI to SIII in this animal. These data are in contrast to demonstrations by other investigators that there is a corticotectal projection from SI cortex in rodents. Apparently there is a fundamental species difference in the organization of descending somatosensory pathways. A corticothalamic projection of the AES was also observed. This descending projection appeared to form a shell of labeled cells and fibers around the ventrobasal complex, but unequivocal terminal labeling within the ventrobasal complex could not be demonstrated. Dense terminal labeling was apparent in the posterior group of thalamic nuclei (PO) where thalamocortical afferents to the AES originate.

scholarly journals К. Schaffer: Zur feineren Struktur der Hirnrinde und über funktionelle Bedeutung der Nervenzellenfortsätze. Arch. f. Mikrosk. Anatomie. XLVIIL 4 Heft. 1897. S. S. 550—572

2020 ◽  
Vol V (3) ◽  
pp. 167-169
Author(s):  
A. E. Smirnov
Keyword(s):  
Cerebral Cortex ◽  
Opposite Direction ◽  
Molecular Layer ◽  
Pyramidal Cells ◽  
Special Group ◽  
The Brain ◽  
Axial Cylinder

The author's research refers to the anterior cerebral cortex of a newborn dog. The author studies in detail the so-called tiny pyramidal cells, lying between the pluripolar cells of the molecular layer and the small (true) pyramidal cells. Already R. y Cajal drew attention to polygonal or core-shaped cells, the cells that lie behind the layer of the outermost cells (pluripolare Nervenzellen von R. y Cajal), but did not separate them into a special group, believing that these cells were gradually changing vid, go into the small pyramids, to which he numbered them. Schaffer separates these cells into a special group, calling it the layer of surface polymorphic cells. These cells have a dark variety of shapes (fusiform, oval, roundish, pear-shaped, polygonal) and lie in approximately four (4) rows. Dendrites go then, mainly, in two opposite directions (for fusiform cells), then they move radially in all directions (for round and polygonal cells). The number of dendrites is sometimes strikingly abundant. Dendrites going to the surface of the brain reach it, while dendrites of the opposite direction sometimes go down to the ammonium formations of the cerebral cortex. Special attention should be paid to the axial cylinder of the disassembled cells; on the basis of the features of this appendix, the author distinguishes 3 types of disassembled cells.

A unitary hypothesis of mind-brain interaction in the cerebral cortex

1990 ◽  
Vol 240 (1299) ◽  
pp. 433-451 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Pyramidal Cells ◽  
Neuronal Structure ◽  
Mental Experience ◽  
Effective Selection ◽  
Global Nature ◽  
The Mind ◽  
Mental Events ◽  
Apical Dendrites ◽  
The Brain

A brief introduction to the brain-mind problem leads on to a survey of the neuronal structure of the cerebral cortex. It is proposed that the basic receptive units are the bundles or clusters of apical dendrites of the pyramidal cells of laminae V and III-II as described by Fleischhauer and Peters and their associates. There are up to 100 apical dendrites in these receptive units, named dendrons. Each dendron would have an input of up to 100000 spine synapses. There are about 40 million dendrons in the human cerebral cortex. A study of the influence of mental events on the brain leads to the hypothesis that all mental events, the whole of the World 2 of Popper, are composed of mental units, each carrying its own characteristic mental experience. It is further proposed that each mental unit, named psychon, is uniquely linked to a dendron. So the mind-brain problem reduces to the interaction between a dendron and its psychon for all the 40 million linked units. In my 1986 paper ( Proc. R. Soc. Lond . B 227, 411-428) on the mind-brain problem, there was developed the concept that the operation of the synaptic microsites involved displacement of particles so small that they were within range of the uncertainty principle of Heisenberg. The psychon-dendron interaction provides a much improved basis for effective selection by a process analogous to a quantal probability field. In the fully developed hypothesis psychons act on dendrons in the whole world of conscious experiences and dendrons act on psychons in all perceptions and memories. It is shown how these interactions involve no violation of the conservation laws. There are great potentialities of these unitary concepts, for example as an explanation of the global nature of a visual experience from moment to moment. It would seem that there can be psychons not linked to dendrons, but only to other psychons, creating what we may call a psychon world.

Tactile neuron classes within second somatosensory area (SII) of cat cerebral cortex

1980 ◽  
Vol 43 (2) ◽  
pp. 292-309 ◽  
Author(s):  
R. E. Bennett ◽  
D. G. Ferrington ◽  
M. Rowe
Keyword(s):  
Cerebral Cortex ◽  
Somatosensory Area ◽  
Cat Cerebral Cortex

Oxygen tensions measured in cat cerebral cortex under hyperbaric conditions

1979 ◽  
Vol 46 (1) ◽  
pp. 53-60 ◽  
Author(s):  
F. G. Hempel
Keyword(s):  
Cerebral Cortex ◽  
Venous Blood ◽  
Sagittal Sinus ◽  
Venous Circulation ◽  
Arterial Blood ◽  
The Mean ◽  
Oxygen Tensions ◽  
The Brain ◽  
Cat Cerebral Cortex ◽  
Hyperbaric Conditions

Pyrenebutyric acid (PBA), the intracellular fluorescent indicator, was used to measure the partial pressure of oxygen (PO2) in the exposed cerebral cortex of anesthetized cats at hyperbaric pressures up to 4 ATA. The validity of the PBA method for determining cortical PO2 was confirmed by demonstrating a precise linear relationship between Pao2 and the reciprocal of the fluorescence of PBA in the brain as the cat was ventilated with sequentially greater oxygen pressures while holding the Paco2 nearly constant. Increments in the Paco2 while the Pao2 was maintained at a high (about 2,000 Torr) level resulted in stepwise greater oxygen tensions in the brain until an oxygenation end point was reached with a Paco2 averaging near 122 Torr. Greater amounts of CO2 did not bring the mean PO2 of the brain, 1,017 Torr, closer to 2,000 Torr. During normocapnia the cortical PO2 was greater than the PO2 of cerebral venous blood collected from the superior sagittal sinus; however, in hypercapnia (PaCO greater than 45 Torr), the PO2 of the sinus blood exceeded the value determined in the cortex. This latter observation is taken as evidence for convective shunting of cerebral arterial blood to venous circulation when hypercapnia is present.

scholarly journals Delineating the Organization of Projection Neuron Subsets with Multi-fluorescent Rabies Virus Tracing Tool

2019 ◽  
Author(s):  
Liang Li ◽  
Yajie Tang ◽  
Leqiang Sun ◽  
Jinsong Yu ◽  
Hui Gong ◽  
...  
Keyword(s):  
Rabies Virus ◽  
Functional Organization ◽  
Projection Neuron ◽  
Projection Neurons ◽  
Thalamic Nuclei ◽  
Corticothalamic Projection ◽  
Virus Tracing ◽  
Layer V ◽  
The Brain ◽  
Layer Vi

AbstractThe elegant functions of the brain are facilitated by sophisticated connections between neurons, the architecture of which is frequently characterized by one nucleus connecting to multiple targets via projection neurons. Delineating the sub-nucleus fine architecture of projection neurons in a certain nucleus could greatly facilitate its circuit, computational, and functional resolution. Here, we developed multi-fluorescent rabies virus to delineate the fine organization of corticothalamic projection neuron subsets in the primary visual cortex (V1). By simultaneously labeling multiple distinct subsets of corticothalamic projection neurons in V1 from their target nuclei in thalamus (dLGN, LP, LD), we observed that V1-dLGN corticothalamic neurons were densely concentrated in layer VI, except for several sparsely scattered neurons in layer V, while V1-LP and V1-LD corticothalamic neurons were localized to both layers V and VI. Meanwhile, we observed a fraction of V1 corticothalamic neurons targeting multiple thalamic nuclei, which was further confirmed by fMOST whole-brain imaging. We further conceptually proposed an upgraded sub-nucleus tracing system with higher throughput (21 subsets) for more complex architectural tracing. The multi-fluorescent RV tracing tool can be extensively applied to resolve architecture of projection neuron subsets, with a strong potential to delineate the computational and functional organization of these nuclei.

scholarly journals Iron Deposition in the Brain Following the Ischemia in a Rat Model of Ischemic Tolerance

2004 ◽  
Vol 47 (4) ◽  
pp. 285-288 ◽  
Author(s):  
Viera Danielisová ◽  
Miroslava Némethová ◽  
Jozef Burda
Keyword(s):  
Cerebral Cortex ◽  
Frontal Cortex ◽  
Rat Model ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Ischemic Tolerance ◽  
Iron Deposition ◽  
Sham Operation ◽  
Vessel Occlusion ◽  
The Brain

Preconditioning of the brain by short-term ischemia increases brain tolerance to the subsequent severer ischemia. In this study, we investigated iron deposition in the cerebral cortex and the ischemic tolerance in a rat model of cerebral ischemia. Forebrain ischemia was induced by four-vessel occlusion for 5 min as ischemic preconditioning. Two days after preconditioning or after the sham-operation, the second ischemia was induced for 20 min. Changes in the cerebral cortex were examined after 1 to 8 weeks of recirculation following 20 min ischemia with or without preconditioning using the iron histochemistry. Granular deposits of the iron were found in the cytoplasm of the pyramidal cells in the layers III and V of the frontal cortex after 1 week of recirculation. When the rats were exposed to 5 min ischemia 2 days before 20 min lasting ischemia, the deposition of iron in the cytoplasm of the pyramidal cells in layers III and V of the frontal cortex was significantly lower during all periods of reperfusion. Preconditioning 5 min ischemia followed by 2 days of reperfusion before 20 min ischemia also prevented degeneration of the pyramidal neurons in layers III and V of the frontal cortex.

scholarly journals VII-The thalamic connections of the parietal and frontal lobes of the brain in the monkey

1935 ◽  
Vol 224 (515) ◽  
pp. 313-359 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Lateral Geniculate Body ◽  
Great Accuracy ◽  
Relay Station ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Cortical Connections ◽  
Sensory Nucleus ◽  
Proper Functions ◽  
The Brain

It is well known that a large proportion of the thalamus proper functions as a relay station through which sensory impulses are projected on to the cerebral cortex. With the exception of the lateral geniculate body (whose detailed relations to the area striata have recently been worked out with great accuracy by Poliak (1933)) the precise relation of the various thalamic nuclei and their subdivisions to the different cortical areas still remains to be established. The investigation of which this communication represents a report was undertaken in the first place in order to define precisely the manner in which the main sensory nucleus of the thalamus (nucleus ventralis) is projected on to the sensory areas of the cortex. We have, however, extended our original plans to include a survey of the thalamo-cortical connections of the greater part of the frontal and parietal regions of the cerebral cortex. The work of previous investigators which bears on this question we will leave for consideration in the discussion at the end of this paper.

scholarly journals SPREAD OF DIRECTLY EVOKED RESPONSES IN THE CAT'S CEREBRAL CORTEX

1959 ◽  
Vol 42 (4) ◽  
pp. 761-777 ◽  
Author(s):  
V. B. Brooks ◽  
P. S. Enger
Keyword(s):  
Cerebral Cortex ◽  
Pyramidal Cells ◽  
Neuromuscular Blocking ◽  
Brain Circulation ◽  
Direct Stimulation ◽  
Synaptic Excitation ◽  
Excitatory State ◽  
Supramaximal Stimulation ◽  
The Brain ◽  
Stimulation Of

A study has been made of the electrical responses to direct stimulation of the exposed cerebral cortex of cats that had been immobilized with neuromuscular blocking drugs, and whose muscle and skin wounds had been locally anesthetized. The characteristics and spread of the first and second surface-negative responses are described. It was found that the first surface-negative response to weak stimuli decays linearly to zero at 3 to 6 mm. from the point of stimulation. Intermediate stimuli cause farther and non-linear spread: responses are re-initiated, or reinforced, at 6 to 10 mm.; and supramaximal stimulation produces reinforcement both at 5 and at 10 mm. The conduction velocity of these responses is uniform for linear spread (0.7 to 2.0 m./sec.), but reinforced responses occur 1 to 3 msec. earlier than would be expected for simple conduction. The phenomenon of re-initiation, or reinforcement, depends upon the excitatory state of the brain; circulation and previous stimulation are important factors. Connections outside the gyrus matter only in so far as they provide other sources of general excitation. It is concluded that two types of transmission: slow and fast, can lead to generation of similar surface-negative responses. The suggestion is made that the slowly conducted surface-negative potentials are due to direct or to synaptic excitation of pyramidal cells; while the responses with shortened latency are initiated synaptically on other pyramidal cells after fast conduction at about 10 m./sec. in tangential fibres.

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