Jack Werboff

Classical Conditioning in Newborn Rats

Newborn albino rats were trained according to classical conditioning procedure wih one of four intervals between conditioned and unconditioned stimuli. A vibrotactile stimulus (conditioned stimulus) paired with an electric shock (unconditioned stimulus) was presented to the forelimb 80 times. The results demonstrate that conditioning takes place in newborn rats. However, levels of performance as a function of time intervals between stimuli did not resemble the levels traditionally reported for older animals.

Behavior Development in the Dog: An Interspecific Analysis

Young dogs were maintained in isolation from other dogs and under varying degrees of exposure to an alien species (mature rabbits). Parametric observations indicate that an interspecific social attachment develops during the initial hours of co-habitation. The later social interaction patterns of the dogs were influenced, but not irrevocably fixed, by the early cross-specific rearing experience.

EFFECTS OF PRENATAL X-RAY IRRADIATION ON AUDIOGENIC SEIZURES IN THE RAT

Abstract Gravid albino rats of the Sprague-Dawley strain received 25, 50, or 100 r whole-body X-ray irradiation on days 5, 10, 15, or 20 of gestation. Controls were sham-irradiated. Over 500 surviving offspring were evaluated for susceptibility to audiogenic seizures under two conditions of threshold testing, with the bell alone and with a pretreatment of Metrazol (16 mg/kg). The tests were conducted when the animals were 120 and 122 days of age. Irradiation on days 5 or 10 of gestation resulted in a decrease in seizure responses, while irradiation on days 15 or 20 of gestation resulted in an increase in seizure responses. The differences were more pronounced under the lowered threshold condition. These findings appeared to be independent of dosage. It was concluded that low levels of prenatal irradiation can alter the threshold of susceptibility to audiogenic seizures in the offspring.

Effects of Aging on Open Field Behavior

In a recent report by Furchtgott, et al. ( 1961 ), exploratory behavior in an open field situation was found to decrease with increasing age. These investigators used naive animals at each age of testing and terminated their study at 390 days of age. The present investigation confirms some of the findings of the above mentioned report, utilizing a different experimental design with repeated testing of the same animals to demonstrate chat the age factor is more important than the novelty of the experience. Additional data on animals tested at an older age and on sex differences are presented for the open field measures. METHOD Sabjects.-Ss were 28 albino rats of the Sprague-Dawley strain purchased from the Holtzman Co. The original group of 12 females and 16 males was reduced by death, disease, and other attrition factors to 12 females and 8 males on whom open field measures at each age were available. Animals were maintained on Purina laboratory chow and water ad libitam throughout their lifetime except for 3 weeks as 100 days of age during which time they were on a 23-hr. water deprivation schedule. Animals arrived in the laboratory at 45 days of age and were routinely weighed and handled at least once a week. At 100 days of age and after the first open field test, they were rested in a maze learning situation. At 360 days of age, attempts were made at macing the animals. Aside from these manipulations, each S received little or no handling and lived his routine life with a same sex cagemate. Apparatzrs and procedure.-The open field test used and the procedure employed was similar to that described by Stern (1956). T he apparatus was 3 by 5 ft., painted black and divided into 15 1-ft. squares marked by a chalk line. Lighting was uniform from overhead and the animals were observed through a one-way vision window. Animals were run for 5 consecutive daily 2-min. trials when 90, 180, 360, and 540 days of age. The number of squares traversed and the number of emotional activities such as defecating, urinating, edging, face washing, rearing, crouching, etc. were recorded.

Febrile Convulsions in Infant Rats, and Later Behavior

At 3 days of age, rats were (i) subjected to a febrile convulsion, or (ii) were handled, or (iii) were not handled. Evaluation at 30 days of age revealed that animals in the first group were heaviest and most resistant to audiogenic seizure stimuli. No differerences were found in maze-learning ability or activity level.

POSTNATAL EFFECTS OF CONTROL FLUIDS ADMINISTERED TO GRAVID RATS

Studies of the effects of drugs and other compounds on animals typically employ injections of the diluting agent to a control group. Diluting agents commonly used are distilled water, saline, and oil. Routes of administration also vary and include the intraperitoneal, subcutaneous, intravenous, and oral. Since previous work in this laboratory has been concerned with the administration of various pharmacologicall agents to pregnant rats and the effects on the behavior of che offspring (Werboff, Gottlieb, Havlena, & Word, 1961; Werboff, Gottlieb, Dembicki, & Havlena, 1961), ic was advisable to invescigate the differences, if any, between the control fluids and routes of administration currently in use. This investigation was undertaken to compare the effects of two control fluids (isotonic saline and distilled water) administered by two different routes (subcucaneous and intraperitoneal) to pregnant rats on the behavior of the offspring.

Postnatal effect of antidepressant drugs administered during gestation.

In a previous study, iproniazid administered to rats during the second trimester of gestation resulted in 100 per cent neonatal mortality. This report compares the effects of iproniazid and isocarboxazid administered prenatally on neonatal mortality and susceptibility to audiogenic seizures. Gravid albino rats of the Sprague-Dawley strain were randomly divided into a control and two drug groups. In every group, the treatment was administered intraperitoneally during one trimester of gestation on days 5 through 8, 11 through 14, or 17 through 20. The control group received 0.5 ml distilled water while the drug groups received either iproniazid (Marsilid, Hoffman-LaRoche) at 8.0, 4.0, or 2.0 mg/kg, or isocarboxazid (Marplan, Hoffman-LaRoche) at 4.0, 2.0, or 1.0 mg/kg. A total of 1047 offspring were born. Neonatal mortality was evaluated daily from birth through 30 days of age. At 45 and 47 days of age respectively, audiogenic seizure stimuli were administered under two conditions of threshold testing. Iproniazid was found to be significantly more toxic to neonatal survival than isocarboxazid or distilled water. Iproniazids effect was uniform throughout all trimesters of gestation, while isocarboxazid was most toxic in the first trimester. Distilled water administered as a control was found to be extremely toxic in the third trimester. Findings were independent of level of dosage. Offspring of both drug groups gave significantly fewer seizure responses than control offspring. The prenatal administration of these antidepressant drugs had a profound effect on neonatal mortality and susceptibility to audiogenic seizures.

Time judgment as a function of electroencephalographic activity.

Abstract Forty-eight male college students made time judgments of 2- and 8-sec intervals under four experimental conditions with photic stimulation selected to alter frequency (wave-count) of EEG activity. The results indicate that subjects with more than 50 per cent alpha in their eyes-closed resting EEG overestimated time in the eyes-open condition in contrast to those subjects with less than 50 per cent alpha. Intermittent photic stimulation resulted in underestimation of the 8-sec interval only. This was not due to changes induced in the EEG. Correlation of wave-count scores and time estimations showed the predicted inverse relation between increased relative frequency of the EEG and underestimation of temporal experience. This investigation has demonstrated that EEG activity is related to estimation of short temporal intervals.

Adrenalectomy of the Pregnant Rat and Behavior of the Offspring

Albino rats were adrenalectomized on either Day 10½ or Day 16½ of gestation. The offspring were reared by foster mothers. At 25, 30, 35, 40, or 45 days of age they were evaluated on the open field and timidity box tests. There were no behavioral or adrenal size differences among the offspring of adrenalectomized and sham-operated or unoperated control mothers. Consistent and significant sex differences on all measures were found, with females showing higher activity, greater emotionality, and larger adrenal glands than the males.

AVOIDANCE CONDITIONING IN THE GUPPY (Lebistes reticulatus)

Acquisition of a conditioned avoidance response has been demonstrated in the guppy. Although no reliable differences were observed between the three CS-US intervals used, the trend of the data showing that fewer trials are required to reach criterion with longer CS-US intervals supports similar observations reported for other species of fish. The use of the guppy for studies of behavioral genetics and behavioral teratology has been considered.