1. ANATOMY AND PHYSIOLOGY OF THE CENTRAL NERVOUS SYSTEM
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These data are in agreement with the findings with autonomic conditioning to brightness discrimination where forebrainless fish perform
better than normals ( Bcrnstein, 1961b). Therefore, certain tasks are
performed better by forebrainless fish than normal animals. Although
these results appear odd there is an increased body of knowledge in
mammals that dernonstratc limbic lesions often lead to improved performance in certain specified tasks. Obviously, one must take the normal
animals’ behavior as a base line for performance and not as maximum
(or 100%) performance on given tasks.
These data support experimental results on the learning and retention
of conditioned avoidance responses by goldfish in a two-way avoidance
task designed to minimize the difficulty of task for forebrainless goldfish
(llewsbury and Bcrnstein, 1969). The fish were in an open shuttlebox
with a minimal barrier at the center and had to cross the barrier at the onset of light (CS) to avoid shock ( U S ) . Forebrainless fish were less active
than normal fish in both pretraining response rate and intertrial spontaneous cross rate. Forebrainless goldfish learned the avoidance response
with a minimal barrier and a 10-sec light shock interval. However, conditioned avoidance learning by forebrainless fish was inferior to normals
when the size of the opening for avoidance was reduced and the light
shock interval was reduced to 4 sec. Removal of the telencephalon produced significant decreases in the performance of a previously learned
avoidance task; however, there was evidence of partial retention (savings) following training, subsequent to forebrain ablation, and retesting.
Since specific lesions of the telencephalon results in specific losses of
reproductive behavior and losses in ability to perform specific learning
tasks the normal function of the telencephalon has been proposed by
Dewsbury and Bernstein (1969) to be best conceptualized as a facilitator for the processing of information. The concept of the forebrain as a
nonspecific energizer should be reexamined in the face of more recent
data.
H. Stimulation of the Telencephalon
Because of the lack of control for spread of current during stimulation, earlier studies on stimulation and behavior must be interpreted with
caution ( Healey, 1957; Segaar, 1965). In more recent studies, chronically
implanted bipolar electrodes have been utilized to stimulate the telencephalon of free swimming goldfish ( Grimni, 1960). Stimulation of the
olfactory crura at 0.075-0.15 niA with pulses of 0.5 msec duration elicited
complete feeding behavior. This included arousal and intention move-
23
These data are in agreement with the findings with autonomic conditioning to brightness discrimination where forebrainless fish perform
better than normals ( Bcrnstein, 1961b). Therefore, certain tasks are
performed better by forebrainless fish than normal animals. Although
these results appear odd there is an increased body of knowledge in
mammals that dernonstratc limbic lesions often lead to improved performance in certain specified tasks. Obviously, one must take the normal
animals’ behavior as a base line for performance and not as maximum
(or 100%) performance on given tasks.
These data support experimental results on the learning and retention
of conditioned avoidance responses by goldfish in a two-way avoidance
task designed to minimize the difficulty of task for forebrainless goldfish
(llewsbury and Bcrnstein, 1969). The fish were in an open shuttlebox
with a minimal barrier at the center and had to cross the barrier at the onset of light (CS) to avoid shock ( U S ) . Forebrainless fish were less active
than normal fish in both pretraining response rate and intertrial spontaneous cross rate. Forebrainless goldfish learned the avoidance response
with a minimal barrier and a 10-sec light shock interval. However, conditioned avoidance learning by forebrainless fish was inferior to normals
when the size of the opening for avoidance was reduced and the light
shock interval was reduced to 4 sec. Removal of the telencephalon produced significant decreases in the performance of a previously learned
avoidance task; however, there was evidence of partial retention (savings) following training, subsequent to forebrain ablation, and retesting.
Since specific lesions of the telencephalon results in specific losses of
reproductive behavior and losses in ability to perform specific learning
tasks the normal function of the telencephalon has been proposed by
Dewsbury and Bernstein (1969) to be best conceptualized as a facilitator for the processing of information. The concept of the forebrain as a
nonspecific energizer should be reexamined in the face of more recent
data.
H. Stimulation of the Telencephalon
Because of the lack of control for spread of current during stimulation, earlier studies on stimulation and behavior must be interpreted with
caution ( Healey, 1957; Segaar, 1965). In more recent studies, chronically
implanted bipolar electrodes have been utilized to stimulate the telencephalon of free swimming goldfish ( Grimni, 1960). Stimulation of the
olfactory crura at 0.075-0.15 niA with pulses of 0.5 msec duration elicited
complete feeding behavior. This included arousal and intention move-