Fig. 2.4. The effect of direct current administered longitudinally (fronto-occipital) through the brain of
the salamander. Upper: the electroencephalogram when the current is oriented frontally positive
(opposite to the normal awake pattern). The EEG demonstrates a typical delta wave pattern of deep
anesthesia, with the magnitude of the delta waves proportional to the current magnitude. The animal
demonstrated all the clinical signs of anesthesia. Lower: the reverse experiment. A deeply anesthetized
animal is exposed to current oriented in the normal awake direction. Much more current is required to
produce an objective response and while the animal did not recover consciousness as a result of the
current passage, the EEG pattern did show signs (alpha waves) of an awake pattern.
Fig. 2.5. The effect of a magnetic field applied across the head of a salamander in a bitemporal
direction. The interaction between the field and a longitudinal electrical current in the brain (if one
was present) would lead to a decrease in the total current delivered along the original fronto-occipital
vector. It was predicted that this would produce a state of anesthesia, and at the level of 3000 gauss
the EEG pattern became one of deep anesthesia with delta wave forms This was accompanied by a loss
of response to painful stimuli.
If, as these experiments seemed to indicate, there was a DC current flow organized in this
fashion in the brain it should be of the same nature as the peripheral currents, and it should be subject
to the same type of interaction with an applied magnetic field. The anatomical complexity of the head
and brain ruled out the possibility of observing an unequivocal Hall voltage, but if the magnetic field
were very high in strength and precisely oriented 90° to the fronto-occipital vector, then a sufficient
number of charge carriers might be deviated from the original current vector to produce a significant
decrease in the normal current along the fronto-occipital vector; possibly even sufficient to produce
loss of consciousness. Even though fields of several thousand gauss were found to be necessary to
produce the effect, the results were unequivocal. At field strengths exceeding 3000 gauss, the animals
were not only nonresponsive to painful stimuli but they also demonstrated the large, slow delta wave
patterns typical of deep anesthesia.
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