Absence of conduction of spreading depression through cortical region damaged by asphyxiation

1964 ◽  
Vol 207 (4) ◽  
pp. 921-924 ◽  
Author(s):  
C. D. Hull ◽  
A. Van Harreveld
Keyword(s):  
Blood Pressure ◽  
Cerebral Cortex ◽  
Spreading Depression ◽  
Nerve Cells ◽  
Cortical Region ◽  
Pass Through

An area of cerebral cortex was asphyxiated for 30–35 min by application of a weight exerting a pressure on the tissue greater than the blood pressure. Three days later the asphyxiated region showed in most experiments a marked loss of nerve cells. The glia seemed to be better preserved. Spreading depression could not be made to pass through the area when asphyxiation had caused substantial neuronal destruction. These observations do not support a possible involvement of the glia in the propagation of spreading depression.

The correlation between discharge times of neighbouring neurons in isolated cerebral cortex

1979 ◽  
Vol 203 (1153) ◽  
pp. 347-360 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Nerve Cells ◽  
Temporal Relation ◽  
Mammalian Brain ◽  
Cortical Region ◽  
Suprasylvian Gyrus ◽  
Intact Brain ◽  
Isolated Cortex ◽  
Intact Cortex ◽  
Spontaneous Discharges

The purpose of the experiments was to find out whether neighbouring neurons in chronic preparations of neurally isolated cerebral cortex are more likely to fire synchronously than are similar neurons in the intact brain. Chronically implanted extracellular microelectrodes were used to obtain simultaneous records of the spontaneous discharges of neighbouring neurons in the suprasylvian gyrus of the unanaesthetized, unrestrained cat. We have examined multi-unit records obtained from neurons in islands of neurally isolated cortex; these records have been compared with similar records from neurons in the same cortical region of the intact brains of control animals. In isolated cortex, neighbouring neurons showed a tendency to discharge in near synchrony. In contrast, there was a random temporal relation between the firing times of adjacent nerve cells of intact cortex, provided the cat was awake. These results, taken together with the relevant observations of other workers, may indicate the manner in which biologically important information is transmitted within the mammalian brain.

Roles of allocortex and centrencephalon in intentionality and consciousness

2007 ◽  
Vol 30 (1) ◽  
pp. 92-93
Author(s):  
Walter J. Freeman
Keyword(s):  
Cerebral Cortex ◽  
Spreading Depression

“Decortication” does not distinguish between removing all cerebral cortex, including three-layered allocortex or just six-layered neocortex. Functional decortication, by spreading depression, reversibly suppresses only neocortex, leaving minimal intentionality. Removal of all forebrain structures except a hypothalamic “island” blocks all intentional behaviors, leaving only tropisms. To what extent do Merker's examples retain allocortex, and how might such residues affect his interpretations?

Leukocyte kinetics in the human lung: role of exercise and catecholamines

1984 ◽  
Vol 57 (3) ◽  
pp. 711-719 ◽  
Author(s):  
A. L. Muir ◽  
M. Cruz ◽  
B. A. Martin ◽  
H. Thommasen ◽  
A. Belzberg ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Peripheral Blood ◽  
Human Lung ◽  
Work Load ◽  
Low Flow ◽  
Epinephrine Infusion ◽  
First Pass ◽  
Pass Through

In six normal supine subjects epinephrine infusion produced a greater leukocytosis with smaller changes in heart rate and blood pressure than did norepinephrine or isoproterenol. Upright exercise in those subjects produced a greater leukocytosis than supine exercise at the same work load. To determine the lung's participation in these events, indium-labeled neutrophils (PMN) were given to four of the subjects. We found that 20–25% were retained in the first pass through the lung when compared with technetium-labeled erythrocytes. The number of labeled PMN in the lung gradually decreased and the number in the spleen and the liver increased. Exercise and catecholamine infusion caused an acceleration in the release of labeled cells from the lung, an increase in both labeled and unlabeled cells in the peripheral blood, and an increase in the number of labeled cells in the liver and spleen. This suggests that increased perfusion of low-flow areas in the lung may contribute to the increased leukocytosis seen in association with both exercise and catecholamine infusion.

Neuronal and glial activity during spreading depression in cerebral cortex of cat

1975 ◽  
Vol 38 (4) ◽  
pp. 822-841 ◽  
Author(s):  
E. Sugaya ◽  
M. Takato ◽  
Y. Noda
Keyword(s):  
Cerebral Cortex ◽  
Spreading Depression ◽  
Field Potential ◽  
Membrane Depolarization ◽  
Simultaneous Recording ◽  
Neuronal Membrane ◽  
Intracellular Potentials ◽  
Dc Potential ◽  
Glial Membrane ◽  
Glial Depolarization

1. Extra- and intracellular potentials were recorded from neurons and glia during spreading depression (SD) in cerebral cortex of cats. The glial membrane depolarized during SD and the time course of depolarization was concurrent with the surface DC change of SD. The glial depolarization evoked by 20-Hz repetitive cortical stimulation disappeared during the negative DC shift of SD. Simultaneous recording of the extra- and intracellular potentials from a single glial cell with a coaxial microelectrode showed that the extracellular DC potential change was of opposite polarity to the glial intracellular potential, which suggests that the slow glial depolarization concurrent with SD is not the field potential. In contrast to glial cells, the neuronal burst discharges as well as the neuronal membrane depolarization associated with SD did not show a close relationship to SD: the neuronal membrane depolarization and discharge were frequently delayed by 10-3- s from the onset of the SD slow wave. Sometimes SD was observed without accompanying neuronal depolarization. The degree of neuronal depolarization was not always correlated with the amplitude of the negative wave of SD. 2. The effect of tetrodotoxin (TTX) on the negative DC potential of SD was examined. Simultaneous recording of glial membrane potential and the neuronal unit activity as well as extracellular DC potential and surface DC potential during SD was performed and the TTX-treated cortex was compared with the normal state. TTX did not change the DC level of the cerebral cortex. SD could be evoked by KCl when neuronal discharge was completely abolished by TTX application...

Cortical Spreading Depression Increases the Phosphorylation of AMP-Activated Protein Kinase in the Cerebral Cortex

2014 ◽  
Vol 39 (12) ◽  
pp. 2431-2439 ◽  
Author(s):  
Emanuela Viggiano ◽  
Davide Viggiano ◽  
Alessandro Viggiano ◽  
Bruno De Luca ◽  
Marcellino Monda
Keyword(s):  
Cerebral Cortex ◽  
Protein Kinase ◽  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Amp Activated Protein Kinase
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