0
Get Alert
Please Wait... Processing your request... Please Wait.
You must sign in to sign-up for alerts.

Please confirm that your email address is correct, so you can successfully receive this alert.

Article   |    
THE CONTROL OF NORMAL AND "CONVULSIVE" BRAIN POTENTIALS
R. W. GERARD; B. LIBET
Am J Psychiatry 1940;96:1125-1152.
View Author and Article Information

The Department of Physiology, University of Chicago.

text A A A
PDF of the full text article.
Abstract

Brain potentials can be used within limits as an index of the action of cerebral neurones. The recorded waves are the envelope of the beats of many single neurones and their profile depends on the shape of the unit potential and the temporal relation of the many units.The isolated frog brain, with relatively few and similar neurones which can be subjected to a wide variety of experimental conditions, is especially favorable for studying the control of potentials. Mammalian brain in situ, so far as similar experiments have been made, shows like behavior.The olfactory bulb of the isolated brain gives an electrical beat, at six per second, larger and more regular than before removal from the frog. Under varied conditions, the frequency, still regular, may be shifted from one to 50 per second and the single wave from a sine to many highly skewed forms constantly repeated. Such patterns indicate strong unison of the many cells and so reproduce the potential profile of the unit.The unit beat is controlled by the metabolism of the cell, oxidative or glycolytic energy supplying the driving force. It is also controlled by a trip mechanism, presumably the cell membrane, which determines the frequency of oscillation at constant drive. Amplitude and frequency vary inversely as the trip mechanism is altered, together as metabolism is changed.Control of cell potentials mainly through metabolism is considered in the cases of: oxygen lack, narcosis, cyanide, glucose lack, insulin, B1 avitaminosis, iodoacetate, and nicotine poisoning. The action and interaction of these and subsequent agents is presented.Control mainly through the trip mechanism is considered for: altered osmotic pressure, sodium, potassium, calcium, magnesium, and hydrogen ions; for neural stimulation and, in more detail, for polarization by constant currents.Unification of the beats of the many units into synchronous or simultaneous patterns must depend on the propagation of nerve impulses or on electric fields and currents. The mechanism of unification is analyzed and tests for its effectiveness are described. The following conditions favor unison: high temperature and calcium, low potassium and sodium, diminution in afferent nerve impulses (in patterns), increased polarization (or injury potentials), the drugs nicotine and caffeine.Further analysis is made with caffeine, which leads to large repeated waves which may travel along the hemisphere. These are described in detail; and also the control of their size, shape, frequency, speed, and direction of travel by temperature and polarization.The spreading caffeine waves are not stopped by nicotine, which blocks synaptic conduction; they cross a complete transection of the hemisphere when the two halves are in good apposition and so in electrical but not neural continuity; and a caffeinized brain can augment the activity of an abutting normal one.It is concluded that, besides neural coordination of separate neurons, a strictly electrical mechanism can regulate nerve cell beats and cause a spreading activation. This may prove of considerable importance in the interpretation of normal activity, electronarcosis, and of the massed "convulsive" action of the cortex in epilepsy.A theoretical explanation of the mechanism of spread is presented. It demands the existence in brain of maintained polarization gradients in certain directions. These have been found present as predicted.

Abstract Teaser
Figures in this Article

Your Session has timed out. Please sign back in to continue.
Sign In Your Session has timed out. Please sign back in to continue.
Sign In to Access Full Content
 
Username
Password
Sign in via Athens (What is this?)
Athens is a service for single sign-on which enables access to all of an institution's subscriptions on- or off-site.
Not a subscriber?

Subscribe Now/Learn More

PsychiatryOnline subscription options offer access to the DSM-5 library, books, journals, CME, and patient resources. This all-in-one virtual library provides psychiatrists and mental health professionals with key resources for diagnosis, treatment, research, and professional development.

Need more help? PsychiatryOnline Customer Service may be reached by emailing PsychiatryOnline@psych.org or by calling 800-368-5777 (in the U.S.) or 703-907-7322 (outside the U.S.).

+

References

+
+

CME Activity

There is currently no quiz available for this resource. Please click here to go to the CME page to find another.
Submit a Comments
Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discertion of APA editorial staff.

* = Required Field
(if multiple authors, separate names by comma)
Example: John Doe



Related Content
Articles
Books
Manual of Clinical Psychopharmacology, 7th Edition > Chapter 1.  >
Gabbard's Treatments of Psychiatric Disorders, 4th Edition > Chapter 27.  >
Gabbard's Treatments of Psychiatric Disorders, 4th Edition > Chapter 27.  >
Gabbard's Treatments of Psychiatric Disorders, 4th Edition > Chapter 27.  >
Gabbard's Treatments of Psychiatric Disorders, 4th Edition > Chapter 27.  >
Topic Collections
Psychiatric News
PubMed Articles