112
TOSHIAKI J. HARA
1970). However, this question requires further study before a definitive
statement can be made.
Intracranial injection of antimetabolites, puromycin, actinomycin D, or
cycloheximide in the homing chinook salmon markedly inhibited 01factory bulbar discrimination between home water and other natural
waters ( Oshima et al., 1969a). Earlier, Rappoport and Daginawala ( 1968)
showed that olfactory stimulation with morpholine induced an increase
in brain nuclear RNA and a change in base ratios in both intact and
split-brain preparations in isolated heads of marine catfish, Gabichthys
felis. Thus, there seems to be agreement that RNA synthesis is part of
memory-establishing mechanism.
By monitoring and three-dimensional photographic techniques, Kleerekoper ( 1967a,b) analyzed certain aspects of orientation through olfaction
in some marine ( Scyliorhinus stellaris, Mustelus mustelus, and Diplodus
sargus) and freshwater ( Zctalurms nebulosus and Lepomis gibbosus)
fishes. Single specimens were placed in an experimental tank, which was
divided into 16 partial compartments by radially placed walls. Direction
of the fishes’ movement, left- and right-hand turns, speed of locomotion,
the frequency of entries into any one compartment, the frequency of
pathways, and the diurnal distribution of total activity were continuously
and automatically recorded with or without odorous stimulation. None of
the fishes studied moved randomly under experimental conditions devoid
of directional cues. The radius of the curve in changing direction was
fixed within relatively narrow limits and seemed to be species-specific;
left- and right-hand turns were not evenly distributed. Such a locomotor
behavior resulted in a nonrandom pattern of relatively rigid parameters.
Introduction of an odor without directional cues caused a drastic change
in these parameters; the radius of the curve in changing direction decreased and the ratio of left-handed to right-handed turns was greatly
changed. When an attractant odor was introduced unidirectionally, none
of the species studied could locate the source, unless the odor was associated with a differential in the rate of water flow. It is, therefore, suggested that an attractant odor releases rheotactic response so that the
localization of the source of the odor takes place through rheotaxis rather
than through osmotropotaxis.
Similarly, Hemmings (196613) made an analysis of the mechanism
of orientation of roach Rutilus rutilus in an odor gradient. The swimming
speed of the fish was not directly related to odor concentration but was
low when fish swam into decreasing concentration and much higher in
the opposite direction; turning was more frequent at the high concentration end of the gradient. These findings cannot be explained simply in
terms of ortho- or klinokinesis. Hemmings suggested that orientation of
TOSHIAKI J. HARA
1970). However, this question requires further study before a definitive
statement can be made.
Intracranial injection of antimetabolites, puromycin, actinomycin D, or
cycloheximide in the homing chinook salmon markedly inhibited 01factory bulbar discrimination between home water and other natural
waters ( Oshima et al., 1969a). Earlier, Rappoport and Daginawala ( 1968)
showed that olfactory stimulation with morpholine induced an increase
in brain nuclear RNA and a change in base ratios in both intact and
split-brain preparations in isolated heads of marine catfish, Gabichthys
felis. Thus, there seems to be agreement that RNA synthesis is part of
memory-establishing mechanism.
By monitoring and three-dimensional photographic techniques, Kleerekoper ( 1967a,b) analyzed certain aspects of orientation through olfaction
in some marine ( Scyliorhinus stellaris, Mustelus mustelus, and Diplodus
sargus) and freshwater ( Zctalurms nebulosus and Lepomis gibbosus)
fishes. Single specimens were placed in an experimental tank, which was
divided into 16 partial compartments by radially placed walls. Direction
of the fishes’ movement, left- and right-hand turns, speed of locomotion,
the frequency of entries into any one compartment, the frequency of
pathways, and the diurnal distribution of total activity were continuously
and automatically recorded with or without odorous stimulation. None of
the fishes studied moved randomly under experimental conditions devoid
of directional cues. The radius of the curve in changing direction was
fixed within relatively narrow limits and seemed to be species-specific;
left- and right-hand turns were not evenly distributed. Such a locomotor
behavior resulted in a nonrandom pattern of relatively rigid parameters.
Introduction of an odor without directional cues caused a drastic change
in these parameters; the radius of the curve in changing direction decreased and the ratio of left-handed to right-handed turns was greatly
changed. When an attractant odor was introduced unidirectionally, none
of the species studied could locate the source, unless the odor was associated with a differential in the rate of water flow. It is, therefore, suggested that an attractant odor releases rheotactic response so that the
localization of the source of the odor takes place through rheotaxis rather
than through osmotropotaxis.
Similarly, Hemmings (196613) made an analysis of the mechanism
of orientation of roach Rutilus rutilus in an odor gradient. The swimming
speed of the fish was not directly related to odor concentration but was
low when fish swam into decreasing concentration and much higher in
the opposite direction; turning was more frequent at the high concentration end of the gradient. These findings cannot be explained simply in
terms of ortho- or klinokinesis. Hemmings suggested that orientation of