Experimental studies on the brain stem. II. Comparative study of the relation of the cerebral cortex to vestibular nystagmus

1919 ◽  
Vol 31 (1) ◽  
pp. 1-16 ◽  
Author(s):  
A. C. Ivy
2019 ◽  
pp. 12-31
Author(s):  
Alan J. McComas

This chapter outlines the history of research meetings dealing with consciousness, beginning with that hosted by Herbert Jasper in the Laurentian mountains of Quebec in 1953. It starts, however, with a brief discussion on ancient scientific approaches to medicine, which was jump-started by the Greek physician, Hippocrates. Afterward, the chapter skips forward two millennia to major figures who made breakthroughs in the field of brain science. It also touches on a central debate that reached its climax a little later, as to which part of the brain was responsible for consciousness. The chapter considers whether it was the cerebral cortex, as had been the prevailing assumption, or if it was the brain stem.


2003 ◽  
Vol 90 (2) ◽  
pp. 539-548 ◽  
Author(s):  
R. W. Guillery

Recent observations of single axons and review of older literature show that axons afferent to the thalamus commonly branch, sending one branch to the thalamus and another to a motor or premotor center of the brain stem. That is, the messages that the thalamus relays to the cerebral cortex can be regarded as copies of motor instructions. This pattern of axonal branching is reviewed, particularly for the somatosensory and the visual pathways. The extent to which this anatomical evidence relates to views that link action to perception is explored. Most pathways going through the thalamus to the cortex are already involved in motor mechanisms. These motor links occur before and during activity in the parallel and hierarchical corticocortical circuitry that currently forms the focus of many studies of perceptual processing.


1972 ◽  
Vol 34 (3) ◽  
pp. 827-833 ◽  
Author(s):  
Robert J. Harmon ◽  
Robert N. Emde

A microcephalic human newborn exhibited a repertoire of spontaneous REM behaviors, including REM smiling, at rates characteristic of a normal newborn comparison group. Cyclical alternations between behavioral REM and non-REM states were also documented. A detailed post-mortem examination supported an inference that this infant had severely impaired functioning of cerebral cortex and limbic system during its brief postuterine life. The findings support a tentative conclusion that the observed spontaneous REM behaviors are mediated through the brain stem and that cerebral structures, including the limbic system, are not necessary for this mediation. The findings are also consistent with previous evidence that the seat of organization of REM and non-REM sleep is in the brain stem.


1935 ◽  
Vol 61 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Leslie T. Webster ◽  
George L. Fite

1. Mice of special strains injected intracerebrally with a 10 per cent emulsion of bacteria-free brain tissue from fatal cases of encephalitis in St. Louis and Kansas City develop a characteristic and fatal encephalitis. 2. Transmission of the disease can be continued indefinitely by injecting the bacteria-free brain tissue from the infected mice into healthy mice. 3. In the injected mice there is a 3 to 4 day incubation period, followed by hyperesthesia, coarse tremors, convulsions, prostration, and death in from 4 to 6 days. 4. The lesions in the mice with experimental encephalitis consist chiefly of perivascular accumulations of mononuclear leucocytes throughout the brain, stem, cord, and the pia, and destruction of pyramidal cells in the lobus piriformis and cornu Ammonis. 5. The human encephalitis brain tissue preserved in glycerine from the time of death of the patient apparently loses its infectivity for mice in about 32 days.


2019 ◽  
pp. 103-122
Author(s):  
Alan J. McComas

This chapter tells the story of the discovery of the reticular activating system. At the same time, the chapter traces various attempts to address the larger question of “waking” the cortex and bringing it to a state of consciousness. It turns to two scientists, Horace Magoun and Giuseppe Moruzzi, both of whom conducted experiments to explore the possible effects on the cerebral cortex of stimulating the brain stem. Since the brain’s reticular formation ended just below the thalamus on either side, it was logical to see if it might alter cortical excitability. The chapter shows how Magoun and Moruzzi came to the conclusion that, through its action on the excitability of the cortex, the reticular formation could control the wakefulness of the brain.


1936 ◽  
Vol 82 (337) ◽  
pp. 99-118 ◽  
Author(s):  
W. E. Le Gros Clark

The sensory material which provides the essential data for conscious activity is conveyed to the higher functional levels of the brain by impulses which stream up the olfactory tracts, the optic tracts, and the tracts of the brain-stem and spinal cord. With the exception only of the olfactory impulses, all these sensory impulses are filtered through the thalamic region of the brain, or diencephalon, before they can be relayed to the cerebral cortex which forms the anatomical substratum of the more elaborate mental processes. It is an interesting fact that, while the functional localization in the cerebral cortex and the functional localization in regard to the numerous fibre tracts in the brain-stem and spinal cord have been established in quite considerable detail by anatomical, physiological and clinical studies extending over many years, the localization and the connections of the various relay mechanisms in the diencephalon still remain obscure. Since the nature of the sensory material which is delivered to the cerebral cortex depends ultimately on the influences and modifications which may be imposed on the afferent impulses during their passage through the diencephalon, it becomes a matter of extreme importance, from the point of view of the study of the physiology of sensation and of psychological interpretation of sensory experience, that attention should be concentrated on this diencephalic mechanism. The minute anatomy of the diencephalon has recently been worked out in great detail, and it is now the task of the anatomist, physiologist and clinician to discover the functional significance of the numerous cell groups and fibre tracts which have been defined.


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