ABSTRACT The present study has explored the optomotor response in two species of mormyrid fish, G... more ABSTRACT The present study has explored the optomotor response in two species of mormyrid fish, Gnathonemus petersii and Brienomyrus niger. Both species tended to follow a black and white striped stimulus pattern under illumination levels of 6, 12, and 60 lx. The optomotor response ceased to occur under 540 lx. The behavioral data support earlier histological findings implicating the mormyrid retina in dim light vision.
Transactions of the American Fisheries Society, 1979
ABSTRACT The temporal pattern of electric organ discharges emitted by a mormyrid fish, Brienomyru... more ABSTRACT The temporal pattern of electric organ discharges emitted by a mormyrid fish, Brienomyrus niger, was affected by two broad spectrum insecticides, dieldrin and malathion, in concentrations of 1 μg/liter. Such discharge patterns have potential as a sensitive and convenient bioassay tool.
Field recordings of electric organ discharges and catches of Marcusenius cyprinoides showed that ... more Field recordings of electric organ discharges and catches of Marcusenius cyprinoides showed that these electric fish form groups and move about in schools. The role electric organ discharges in group cohesion was investigated by comparing interactions in groups of intact and operated, electrically silent fish. The absence of electric organ dischares reduced locomotor activity and resulted in the disappearance of two behaviors: parallel lineup and single file swimming. Electric signals are considered part of a schooling mechanism that aids the fish in maintaining group cohesion in their turbid enviornment and during migration at night.
Moving about the web the spider Agelena labyrinthica continuously adjusts the prospective return ... more Moving about the web the spider Agelena labyrinthica continuously adjusts the prospective return angle. The amount of path integration was indicated by two compromise angles, return angle e and goal angle ? (Fig. 2). The spider was primed to one of two perpendicular light azimuths, L1 or L2. Subsequently, the discrete effects of a 90° change in light azimuth on the return direction were recorded (Fig. 3). When primed to L1, and the spider was exposed to L2: (1) while homebound, the deviation from straight home was clockwise and largest, (2) both while outbound and returning, the deviation was smallest (Fig. 4), (3) while outbound, either during the first or second half of the outbound run, the deviations were between those obtained in (1) and (2). When the spider was primed to L1, but given L2 while outbound and L1 again while homebound, Agelena deviated counterclockwise, the most with L2 on during the entire outbound run, and less when L2 was available only during a portion of the outbound run. The degree of adjustment of the home path direction is not correlated with the actual path length but with the shortest distance (‘bee line’) between the two points during which the spider was exposed to one of the two light azimuths.
The aim of this study was to allow nonhuman animals to control their environment using operant co... more The aim of this study was to allow nonhuman animals to control their environment using operant conditioning procedures and to assess the effect of control on cognitive tasks. The study tested 4 predictions: (a) rats (Rattus norvegicus) will control a light stimulus; (b) animals will exhibit preferences for particular stimulus strengths; (c) animals who exert control over environmental stimuli will show improved performance on cognitive tasks compared with animals who lack control; and (d) at the end of the operant phase, experimental subjects will have lower corticosterone levels than animals who lack control. Experimental subjects did show control over a light stimulus and performed significantly better over time in a discrimination task compared with subjects who could not control their environment. There was no difference in corticosterone levels between control and experimental subjects. The results will both contribute to our understanding of how control of environmental stimuli affects the welfare of animals in captive environments and aid in designing experimental conditions that will increase validity and reliability in research.
ABSTRACT The present study has explored the optomotor response in two species of mormyrid fish, G... more ABSTRACT The present study has explored the optomotor response in two species of mormyrid fish, Gnathonemus petersii and Brienomyrus niger. Both species tended to follow a black and white striped stimulus pattern under illumination levels of 6, 12, and 60 lx. The optomotor response ceased to occur under 540 lx. The behavioral data support earlier histological findings implicating the mormyrid retina in dim light vision.
Transactions of the American Fisheries Society, 1979
ABSTRACT The temporal pattern of electric organ discharges emitted by a mormyrid fish, Brienomyru... more ABSTRACT The temporal pattern of electric organ discharges emitted by a mormyrid fish, Brienomyrus niger, was affected by two broad spectrum insecticides, dieldrin and malathion, in concentrations of 1 μg/liter. Such discharge patterns have potential as a sensitive and convenient bioassay tool.
Field recordings of electric organ discharges and catches of Marcusenius cyprinoides showed that ... more Field recordings of electric organ discharges and catches of Marcusenius cyprinoides showed that these electric fish form groups and move about in schools. The role electric organ discharges in group cohesion was investigated by comparing interactions in groups of intact and operated, electrically silent fish. The absence of electric organ dischares reduced locomotor activity and resulted in the disappearance of two behaviors: parallel lineup and single file swimming. Electric signals are considered part of a schooling mechanism that aids the fish in maintaining group cohesion in their turbid enviornment and during migration at night.
Moving about the web the spider Agelena labyrinthica continuously adjusts the prospective return ... more Moving about the web the spider Agelena labyrinthica continuously adjusts the prospective return angle. The amount of path integration was indicated by two compromise angles, return angle e and goal angle ? (Fig. 2). The spider was primed to one of two perpendicular light azimuths, L1 or L2. Subsequently, the discrete effects of a 90° change in light azimuth on the return direction were recorded (Fig. 3). When primed to L1, and the spider was exposed to L2: (1) while homebound, the deviation from straight home was clockwise and largest, (2) both while outbound and returning, the deviation was smallest (Fig. 4), (3) while outbound, either during the first or second half of the outbound run, the deviations were between those obtained in (1) and (2). When the spider was primed to L1, but given L2 while outbound and L1 again while homebound, Agelena deviated counterclockwise, the most with L2 on during the entire outbound run, and less when L2 was available only during a portion of the outbound run. The degree of adjustment of the home path direction is not correlated with the actual path length but with the shortest distance (‘bee line’) between the two points during which the spider was exposed to one of the two light azimuths.
The aim of this study was to allow nonhuman animals to control their environment using operant co... more The aim of this study was to allow nonhuman animals to control their environment using operant conditioning procedures and to assess the effect of control on cognitive tasks. The study tested 4 predictions: (a) rats (Rattus norvegicus) will control a light stimulus; (b) animals will exhibit preferences for particular stimulus strengths; (c) animals who exert control over environmental stimuli will show improved performance on cognitive tasks compared with animals who lack control; and (d) at the end of the operant phase, experimental subjects will have lower corticosterone levels than animals who lack control. Experimental subjects did show control over a light stimulus and performed significantly better over time in a discrimination task compared with subjects who could not control their environment. There was no difference in corticosterone levels between control and experimental subjects. The results will both contribute to our understanding of how control of environmental stimuli affects the welfare of animals in captive environments and aid in designing experimental conditions that will increase validity and reliability in research.
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