Pigeon Samples Research Articles

MOST DIRECTED FORGETTING IN PIGEONS CAN BE ATTRIBUTED TO THE ABSENCE OF REINFORCEMENT ON FORGET TRIALS DURING TRAINING OR TO OTHER PROCEDURAL ARTIFACTS

In research on directed forgetting in pigeons using delayed matching procedures, remember cues, presented in the delay interval between sample and comparisons, have been followed by comparisons (i.e., a memory test), whereas forget cues have been followed by one of a number of different sample-independent events. The source of directed forgetting in delayed matching to sample in pigeons was examined in a 2 x 2 design by independently manipulating whether or not forget-cue trials in training ended with reinforcement and whether or not forget-cue trials in training included a simultaneous discrimination (involving stimuli other than those used in the matching task). Results were consistent with the hypothesis that reinforced responding following forget cues is sufficient to eliminate performance deficits on forget-cue probe trials. Only when reinforcement was omitted on forget-cue trials in training (whether a discrimination was required or not) was there a decrement in accuracy on forget-cue probe trials. When reinforcement is present, however, the pattern of responding established during and following a forget cue in training may also play a role in the directed forgetting effect. These findings support the view that much of the evidence for directed forgetting using matching procedures may result from motivational and behavioral artifacts rather than the loss of memory.

Streptococcus bovis infections in pigeons: virulence of different serotypes

In a first experiment, the relative virulence for pigeons of 5 strains of S. bovis was assessed by experimental inoculations. Two S. bovis serotype 1 strains, one serotype 2 strain and two serotype 3 strains were examined. One of the serotype 1 strains and the serotype 2 strain were isolated from pigeons that died from septicaemia. The other strains were isolated from cloaca samples of healthy pigeons. For each strain, 10–20 pigeons were intravenously inoculated with 1 × 10 9 CFU. Morbidity after infection with the serotype 1 and 2 strains varied between 75% and 90%. Disease signs included inability to fly, lameness, emaciation, production of slimy, green droppings, polyuria and sudden death. In groups of pigeons inoculated with the serotype 3 strains, morbidity was 0% and 6%, respectively. Results demonstrate that serotype 3 strains are less virulent for pigeons than serotype 1 and 2 strains. In a second experiment, bacteriological and histological examinations were performed on organs of pigeons serially killed between 1 and 10 days after experimental inoculation with an S. bovis serotype 3 strain of low virulence. Results were compared with results of studies carried out with a highly virulent serotype 1 strain. Notwithstanding bacterial spread and replication in various organs of inoculated pigeons, clinical disease was not observed and histological lesions were scarce and of limited extent.

Gas chromatographic determination of organophosphorus insecticides and their dialkyl phosphate metabolites in liver and kidney samples

A method is described for the quantitative determination of organophosphorus insecticides and six dialkyl phosphate metabolites in animal tissues. The procedure relies on solvent extraction, automated gel permeation chromatography cleanup, and gas chromatographic analysis with flame photometric detection. Tetrabutylammonium hydroxide is utilized as the derivatization reagent for dialkyl phosphate metabolite analysis. Method detection limits ranged from 0.02 to 0.05 ppm for the compounds studied. The method was applied to the analysis of liver and kidney samples of pigeons exposed to diazinon and parathion. Residue levels were confirmed by mass spectrometry, using selected ion monitoring.

Towards the map of the homing pigeon?

The behaviour of pigeons, Columba liva, homing from different sites was used to generate a geographical map based on empirical data. With the help of cluster analysis, release sites were grouped into clusters of sites according to similarities in the initial orientation of the pigeons when released. These similarities in initial orientation were assumed to reflect similarities in the information of the map component. The initial orientation of samples of pigeons was characterized by the length of the mean vector and the angular deviation of the mean vanishing direction from the home direction. According to this analysis the map information is distributed in distinct patches extending over several tens of kilometres. Exposing pigeons to air collected within one of these patches but releasing them after anaesthesia of their olfactory mucosae at a site opposite to the home loft within a different patch resulted in disorientation. This experiment, however, yielded significant differences between control and experimental pigeons within only two out of four distinct patches. This suggests that the map has an airborne component. Parts of the map, however, are based on other physical cues. How these ‘landmarks’ could be used for navigation even when the perception of one or the other component has been eliminated is discussed.

QUANTIFICATION OF THE EFFECTS OF CHLORPROMAZINE ON PERFORMANCE UNDER DELAYED MATCHING TO SAMPLE IN PIGEONS

The effects of four doses of chlorpromazine (dose range 0.5 to 12.5 mg/kg) on performance under a delayed matching-to-sample procedure in pigeons was investigated, using the exponential model of memory (White, 1985). Performance was measured using a bias-free measure of discriminability, log d (Davison & Tustin, 1978), and negative exponential functions were fitted to individual-subject and group data at each dose level. A decrease in matching accuracy was found to be caused by an increase in the rate of forgetting, b, and a decrease in the initial discriminability, log d0. Changes in rate of forgetting and discriminability occurred at doses that had no statistically significant effect on response latency. The exponential model of memory accounted well for the data and provided a useful way of quantifying the effects of chlorpromazine on the processes involved in delayed matching-to-sample performance.

Matching to element and compound samples in pigeons: The role of sample coding.

Matching to element and compound samples in pigeons: The role of sample coding.

Some observations of the effects of intertrial interval and delay on delayed matching to sample in pigeons.

Some observations of the effects of intertrial interval and delay on delayed matching to sample in pigeons.

Some observations of the effects of intertrial interval and delay on delayed matching to sample in pigeons.

Accuracy of delayed matching to sample was studied in pigeons at different combinations of length of intertrial interval and length of delay. When intertrial interval and delay were varied between sessions in Experiments 1 and 2, accuracy increased monotonically with intertrial interval and decreased monotonically with delay. Evidence was found for constancy of performance at equivalent ratios of intertrial interval to delay, and percentage of correct choices was linearly related to the log of this ratio. In Experiments 3 and 4, intertrial interval was manipulated as a within-sessions variable. In contrast to the effect of this variable when manipulated between sessions, accuracy improved only from the shortest interval to the next shortest interval and remained constant at all longer intervals. In Experiment 4, it was found that performance improved as a direct function of the mean intertrial interval for sessions and that this relation was not affected by the degree of intertrial interval variability within sessions. These findings resemble the effects of temporal variables on autoshaping, and the possibility is discussed that some common processes are involved in delayed matching and autoshaping.

Interference of delayed matching to sample in pigeons: Effects of interpolation at different periods within a trial and stimulus similarity

Delayed matching-to-sample performance by pigeons was interfered with by displaying a monochromatic annulus around the center (sample) pecking key. The wavelength of the annulus and its point of interpolation within a trial were varied to determine possible differential effects on matching accuracy. Experiment 1 showed that delayed matching was most disrupted when the interference stimulus (570 nm, 630 nm, or achromatic white) appeared during the delay interval of a trial. Little if any disruption occurred when the interference stimulus was present during the sample and choice periods. The spectral relationship between the chromatic interference stimuli (570 and 630 nm) and the sample stimuli (570 and 630 nm) did not consistently influence the degree to which matching accuracy was affected in any interpolation condition. Experiment 2 found a similar pattern of within-trial effects when the interference stimulus was simply a change from a white achromatic annulus to a chromatic one. This finding indicates that illumination changes, such as the popular houselight variation, are not necessary to produce interference in delayed matching to sample. Even with illumination held constant, however, performance was not differentially sensitive to the similarity between interference and sample stimulus wavelengths. It is suggested that other experiments showing similarity effects in interference of delayed matching to sample were conducted in such a way that subjects confused the interfering stimuli with the samples.

Genetic difference in the sympathetic nervous activity and susceptibility to atherosclerosis in pigeon

Norepinephrine (NE) accumulation, dose response to NE and NE content were studied in the aortas of White Carneau (WC) and Show Racer (SR) pigeons in order to determine if a correlation exists between the atherosclerosis susceptibility of WC and atherosclerosis resistance of SR with the degree of sympathetic nerve ending activity. In addition, the age factor was included by comparing results in 4–14 month-old and 5-year-old animals. NE accumulation by abdominal aorta samples from SR pigeons of both age groups and by thoracic segments from 5-year-old SR was significantly higher than that by WC pigeon samples. The difference in NE accumulation had lower P-values in older than in younger pigeons. Maximal contraction of SR abdominal aorta was significantly higher than that of WC samples. The ED 50 to exogenous NE decreased with age in both strains but the decrease was statistically significant only in WC strain. Finally, NE content of abdominal aorta segments was significantly higher in SR than in WC pigeons. NE content of thoracic aorta did not differ in the 2 strains. The results complement our previous work indicating that sympathetic nerve endings in the vessel wall may have atrophic influence which modulates the metabolic pattern of the arteries. Thus, atherosclerosis and perhaps age, are related degenerative vascular changes associated with reduced indices of sympathetic activity.

Ornithosis (Psittacosis) in Pigeons and Its Relation to Human Pneumonitis

In a previous paper, it was reported that a psittacosis-like virus had been isolated from the lung of a patient who had been exposed to a flock of racing pigeons (Columba livia). Nineteen, or 63%, of the 30 suspected birds gave specific complement-fixation reactions in dilutions of from 1 :8 to 1 :256 (Table I). A virus, indistinguishable from that of the patient, was isolated from the spleens and livers of 4 pigeons which had given a positive, and from 1 pigeon which had given a negative serum reaction. This observation was the prelude to the recognition of the nation-wide existence of a psittacosis-like infection in pigeons—in the future to be described as “Ornithosis.” At least 10 human atypical pneumonias with 2 deaths [California 4 (2 deaths), New York 4, Minnesota 1 and Boston 1] have been traced to exposure to the different species of pigeons exclusively. Survey of Pigeon Lofts and Isolation of Virus. In order to secure comparative data relative to the extent of ornithosis in lofts and to have available suitable birds for experimental tests, random samples of pigeons were secured from various places in California and other states of the Union. With the exception of 12 squabs from a loft whose old birds were virus-carriers, a universal existence of the infection was recognized with the aid of complement-fixation tests. The virus responsible for these reactions was isolated from the organs of non-reacting as well as of reacting pigeons. The pertinent data thus far obtained are summarized in Table I. The extraordinarily high percentage of positive results will doubtless raise questions regarding the specificity of the serum-reactions. There is conclusive evidence that they are the result of a response to a psittacotic antigen.