56
JERALD J. BERNSTEIN
inant activity of the medulla was 8-13 Hz with a less-pronounced low
frequency activity. After a few scconds of delay, the onset of light
induced an increase in the discharges of the dominant 8-13 Hz mode.
Evoked responses induced by acoustic stimulation ( clicks) were recorded
only from the medulla oblongata and never from other parts of the brain.
The amplitudes of these potentials reached between 80-110 mV with
stimulations of 25 clicks/sec. The evoked response followed up to frequencies of 100-140 clicks/ sec. Increasing the frequency to 80 clicks/ sec
generated 2 3 high spikelike potentials of large amplitude which usually
were followed by 2-4 rhythmic waves of 0.5-1.0 sec duration. Cessation
of acoustic stimulation was either followed by no response or a spike
potential followed by a volley of high frequency waves. Noise in the
room during the time of the experiment occasionally could prevent the
appearance of 8-13 Hz activity in the cod indicating that acoustic
stimulation can result in “arousal.”
Electroencephalograms were also obtained from the medulla oblongata of goldfish (Schadk and Weiler, 1959). The wave forms were
characterized by slow 0.5-2.0 Hz potentials of low amplitude. In addition, two groups of high frequency waves were superimposed on this
slow rhythm resulting in a pattern of 8-11 Hz dominate in the dark, and
a pattern of 20-35 Hz observed during light narcosis or during general
illumination of the room. Unlike the cod, the electrical activity of the
medulla of goldfish was not influenced noticeably by light or noise.
However, the recordings from the medulla were made from the gustatory
or vagal lobes which could result in the lack of photic or acoustically
induced responses ( Schadk and Weiler, 1959).
C. fieticdomotor System
The electrical activity of the medullary reticular cells of the dogfish, Squulua lebruni, were studied using glass micropipettes ( Restieaux
and Satchell, 1958). Reticular cells in the medulla of this fish were extremely large, 40-Sop in diameter and as much as 200-25Op long.
Groups of reticular cells lie on either side of and send their axons into
the medial longitudinal fasciculus. The reticular motor nerve fibers
descended into the midline of the floor of the medulla to relay information to the motor neurons of the efferent output to the musculature of
the trunk and tail. Using intracellular electrodes it was found that the
resting membrane potential varied between 60-70 mV in amplitude.
Action potentials attained amplitudes of 70-120 mV. The action potential
was followed by a post-spike hyperpolarization which followed the fall-
JERALD J. BERNSTEIN
inant activity of the medulla was 8-13 Hz with a less-pronounced low
frequency activity. After a few scconds of delay, the onset of light
induced an increase in the discharges of the dominant 8-13 Hz mode.
Evoked responses induced by acoustic stimulation ( clicks) were recorded
only from the medulla oblongata and never from other parts of the brain.
The amplitudes of these potentials reached between 80-110 mV with
stimulations of 25 clicks/sec. The evoked response followed up to frequencies of 100-140 clicks/ sec. Increasing the frequency to 80 clicks/ sec
generated 2 3 high spikelike potentials of large amplitude which usually
were followed by 2-4 rhythmic waves of 0.5-1.0 sec duration. Cessation
of acoustic stimulation was either followed by no response or a spike
potential followed by a volley of high frequency waves. Noise in the
room during the time of the experiment occasionally could prevent the
appearance of 8-13 Hz activity in the cod indicating that acoustic
stimulation can result in “arousal.”
Electroencephalograms were also obtained from the medulla oblongata of goldfish (Schadk and Weiler, 1959). The wave forms were
characterized by slow 0.5-2.0 Hz potentials of low amplitude. In addition, two groups of high frequency waves were superimposed on this
slow rhythm resulting in a pattern of 8-11 Hz dominate in the dark, and
a pattern of 20-35 Hz observed during light narcosis or during general
illumination of the room. Unlike the cod, the electrical activity of the
medulla of goldfish was not influenced noticeably by light or noise.
However, the recordings from the medulla were made from the gustatory
or vagal lobes which could result in the lack of photic or acoustically
induced responses ( Schadk and Weiler, 1959).
C. fieticdomotor System
The electrical activity of the medullary reticular cells of the dogfish, Squulua lebruni, were studied using glass micropipettes ( Restieaux
and Satchell, 1958). Reticular cells in the medulla of this fish were extremely large, 40-Sop in diameter and as much as 200-25Op long.
Groups of reticular cells lie on either side of and send their axons into
the medial longitudinal fasciculus. The reticular motor nerve fibers
descended into the midline of the floor of the medulla to relay information to the motor neurons of the efferent output to the musculature of
the trunk and tail. Using intracellular electrodes it was found that the
resting membrane potential varied between 60-70 mV in amplitude.
Action potentials attained amplitudes of 70-120 mV. The action potential
was followed by a post-spike hyperpolarization which followed the fall-