18
JERALD J . BERNSTEIN
surface electrodes on the telencephalon of goldfish, Carassius auratus,
reveal a dominant electrical pattern of spontaneous low amplitude electrical potentials of 9-14 Hz in a quiet, dark room ( SchadC, 1959; Schadk
and Weiler, 1959). These waves tended to be accentuated by general
illumination levels or moderate sounds in the room. Occasionally a telencephalic alpha rhythm was present in the animals, demonstrating what
has been classified as “arousal” in higher vertebrates. Although the spontaneous electrical activity of the fish telencephalon can be influenced
by visual and auditory stimuli, evoked responses cannot be elicited in
the telencephalon after visual or auditory stimuli ( Karamyan, 1956).
Electroencephalograms recorded from the telencephalon of codfish,
Gadus callurias, show a dominant rhythm of low amplitude 8-13 Hz
rhythm (Enger, 1957). However, slower rhythms of less than 7 Hz were
most pronounced in the telencephalon, but they were relatively unaffected by changes in the environment.
E. Telencephalon and Reproductive Behavior
The telencephalon plays an important but varied role in the reproductive behavior of fishes. Removal of both hemispheres of the telcncephalon of Hemichromis biniaculatus and Betta splendens resulted in
complete loss of all sexual behavior. However, complete removal of the
telencephalon of Tilapia macrocephala only resulted in the loss of specific
portions of the mating behavior (Aronson, 1948). There were differential losses in courtship behavior such as a decrease in nest building
activity and deficits in the ability of males to fertilize the eggs. Subtotal
extirpation of the telencephalon of the guppy, Lebistes reticulatus,
inhibited but did not prevent normal mating and aggressive behavior
whereas complete removal of the telencephalon in Xiphophomcs maculatus resulted in a depression of the frequency of copulation with no
indication that any sexual pattern within the courtship of the animal
could be completely eliminated ( Kamrin and Aronson, 1954). Since
removal of the telencephalon did not eliminate the behavior it was suggested that there is a facilitative action of the telencephalon on lower
centers and that the telencephalon does not play a direct role in the
organization of sexual behavior pattern. Thus, Aronson ( 1967 ) characterized the telencephalon as a general sensitizor or facilitator of mechanisms
present in lower portions of the brain (Kamrin and Aronson, 1954).
Removal of portions of the telencephalon of the stickleback, Gasterosteus aculeatus, resulted in losses of specific aspects of reproductive
behavior and weakening of sequential patterns of its complex series of
JERALD J . BERNSTEIN
surface electrodes on the telencephalon of goldfish, Carassius auratus,
reveal a dominant electrical pattern of spontaneous low amplitude electrical potentials of 9-14 Hz in a quiet, dark room ( SchadC, 1959; Schadk
and Weiler, 1959). These waves tended to be accentuated by general
illumination levels or moderate sounds in the room. Occasionally a telencephalic alpha rhythm was present in the animals, demonstrating what
has been classified as “arousal” in higher vertebrates. Although the spontaneous electrical activity of the fish telencephalon can be influenced
by visual and auditory stimuli, evoked responses cannot be elicited in
the telencephalon after visual or auditory stimuli ( Karamyan, 1956).
Electroencephalograms recorded from the telencephalon of codfish,
Gadus callurias, show a dominant rhythm of low amplitude 8-13 Hz
rhythm (Enger, 1957). However, slower rhythms of less than 7 Hz were
most pronounced in the telencephalon, but they were relatively unaffected by changes in the environment.
E. Telencephalon and Reproductive Behavior
The telencephalon plays an important but varied role in the reproductive behavior of fishes. Removal of both hemispheres of the telcncephalon of Hemichromis biniaculatus and Betta splendens resulted in
complete loss of all sexual behavior. However, complete removal of the
telencephalon of Tilapia macrocephala only resulted in the loss of specific
portions of the mating behavior (Aronson, 1948). There were differential losses in courtship behavior such as a decrease in nest building
activity and deficits in the ability of males to fertilize the eggs. Subtotal
extirpation of the telencephalon of the guppy, Lebistes reticulatus,
inhibited but did not prevent normal mating and aggressive behavior
whereas complete removal of the telencephalon in Xiphophomcs maculatus resulted in a depression of the frequency of copulation with no
indication that any sexual pattern within the courtship of the animal
could be completely eliminated ( Kamrin and Aronson, 1954). Since
removal of the telencephalon did not eliminate the behavior it was suggested that there is a facilitative action of the telencephalon on lower
centers and that the telencephalon does not play a direct role in the
organization of sexual behavior pattern. Thus, Aronson ( 1967 ) characterized the telencephalon as a general sensitizor or facilitator of mechanisms
present in lower portions of the brain (Kamrin and Aronson, 1954).
Removal of portions of the telencephalon of the stickleback, Gasterosteus aculeatus, resulted in losses of specific aspects of reproductive
behavior and weakening of sequential patterns of its complex series of