Effect of person and environment on heart rates in two strains of pointer dogs

Several recent studies have shown that there is a general and marked canine cardiac response to humans and to petting from humans. Additional investigations have suggested that one of the major determinants of such responding is genetic. Some studies have indicated that such a response does not occur in nervous, short-haired pointer dogs. Evidence presented in this study indicates that a heart rate response to person and petting does occur in both the nervous as well as the normal pointer dog, but only when the animal is unrestrained. When placed in a restraining harness, only normal dogs showed a heart rate response to person and the characteristic bradycardia upon petting. Moreover, in this and two other separate experiments in which tones (CS’s) were given, it was observed in both normal and nervous strains that mean baseline heart rates were as much as 40 beats per minute lower in the restrained situation than in the unrestrained situation. These experiments measured retention of cardiac response to aversive conditional signals, since most dogs (9 of 12) had received both tones and shock in a bar jumping-shock avoidance experiment one year previously. However, heart rates varied inconsistently in both magnitude and direction of change upon CS showing little or no retention. These findings clarify ambiguity in previous reports and again show that the restraining conditions in an experiment can constitute a serious stress for the animal and be a major factor in the results.     

Human sex differences in extreme isolation.

This report compares the responses of male and female adult subjects in the water-immersion sensory-isolation environment. Endurance, subjective time estimates, and heart rate were dependent variables. Duration under water, with voluntary termination possible, was an average of about 4 hr. for both males and females. Subjective estimate of total time in isolation averaged about 3 1/2 hr. for females and almost 4 hr. for males. Subjective time estimate of consecutive 30-min. time intervals was a bit more than 30 min. for males and about 33 min. for females. Mean heart rate (beats/minute) averaged in the 80s for both groups. None of these differences is statistically significant. This study clarifies the mixed findings reported in the literature as to sex differences in isolated environments.     

Human visual evoked responses are related to heart rate.

The purpose of the present experiment was to determine the relation between changes in heart rate and averaged evoked potentials. Sixteen male subjects with variable heart rates received 50 flashes of light during fast heart beats, 50 during slow heart beats, and 50 during midrange heart rate level. Evoked responses were recorded from the scalp overlying the right and left occipital lobes. Heart rate, respiration, eye movements, and cephalic blood flow were also recorded. The results indicated that spontaneous changes in heart rate are related to changes in visual evoked responses and that this relation differs for the two cerebral hemispheres. Furthermore, cephalic pulse amplitude was largest following slow heart beats and smallest following fast heart beats, which suggests that changes in heart rate are related to changes in cerebrovascular as well as electrocortical activity. The results are discussed in terms of formulations derived from behavioral studies regarding the relation between cardiovascular activity and attentional processes.     

Effect of dopamine on diuresis and its role in forming a renal CR

Four female mongrel dogs were used. Three had both ureters transplanted to the surface of the abdomen and one had a unilateral nephrectomy on the left and the right ureter transplanted to the abdomen. In dogs with externalized ureters our results with dopamine show changes in cardiac rate and renal secretion. The method used was 1) injection of dopamine, 2) measurement of subsequent changes in renal secretions (unconditional reflex), 3) and heart rate (HR). After 40 daily injections im of 2.5 mg/kg in normal saline the possible production of a diuretic CR was tested by injecting normal saline im and a tone was used as a signal. The control for normal saline showed no change in HR nor any of the constituents measured. The dopamine injection resulted in an increase of epinephrine in the urine of 300–600 per cent for 45 minutes; of norepinephrine of 200–500 per cent for 45 minutes; of an increase of 50 per cent in urine volume for 45 or more minutes; of absolute Na secretion of 49 per cent, of K, 20 per cent; of creatinine, 39 per cent (average in 3 dogs for 45 minutes diuresis). When the conditional stimulus (normal saline and tone) was given after several months training with the conditional signal and the injection of dopamine, there was no significant CR change to the HR nor any of the above components of urine. The conclusion is that in spite of the great increase of urine volume and composition of above substances there was no significant increase to the signals for the im injection of dopamine,i.e., no conditioning to dopamine.     

Parallel between antianxiety and cardiovascular effects of chlordiazepoxide in genetically nervous dogs

There is evidence that cardiac arrhythmias are partially of CNS origin, and that certain drugs affect arrhythmia, both positively and negatively, through CNS action. We hypothesized and confirmed that chlordiazepoxide diminished the well-established incidence of arrhythmias (A-V blocks and nodal escapes) in five nervous pointer dogs. It is known that this drug normalizes behavior and aids in the bar-pressing performance of nervous dogs. Nervous dogs tend to have low heart rates (HRs) while normals have higher HRs. Chlordiazepoxide increased HRs in our five nervous dogs, and we postulated that HR increase would be less or none in normals. This was confirmed in a later study of five normals. A further study of eight normal dogs and eight nervous dogs essentially reproduced these findings, suggesting the possibility that the slow heart rates and the behavioral abnormality have a common basis, expected to be some CNS biochemical lesion.     

Conditioning the cardiorespiratory dynamics of locomotion in dogs

In 17 dogs blood pressure in the carotid artery, heart rate, pneumogram and actogram of the hind leg were recorded during rest and during locomotion on a treadmill. The increases in cardiorespiratory dynamics which occurred during locomotion were then conditioned. The conditional stimulus was represented by the noise and vibration of the treadmill. It was determined that conditional changes in cardiorespiratory dynamics can be formed quickly on the basis of locomotion. Qualitatively the changes were the same as the unconditional changes, and their magnitude was 60 to 70 per cent that of the unconditional changes. Conditional increase in cardiorespiratory dynamics was most intensive in the first 30 seconds from the onset of the conditional stimulus. In acute extinction of these conditional changes, movements of the extremities were inhibited first, followed by inhibition of increased blood pressure, then inhibition of increased heart rate, and last, inhibition of increased respiratory rate. In another series of experiments on five dogs cardiorespiratory responses were conditioned to a sudden change from moderate locomotion (50 m per min) to rapid locomotion (200 m per min). Increased cardiorespiratory dynamics could be conditioned easily. Increased circulation of blood and increased respiratory rate on exposure to conditional stimuli signalling muscular exertion can be considered an important preparation of the organism for actual muscular activity. This preparation also takes place in natural life conditions.     

Do dogs (Canis familiaris) seek help in an emergency?

The question of whether dogs recognize an emergency and understand the need to seek help from a bystander was tested in two experiments. In the first experiment, dogs' owners feigned a heart attack in an open field, and in the second experiment, dogs' owners experienced an accident in which a bookcase fell on them and pinned them to the floor. In these experiments, one or two bystanders were available to which dogs could go for help. The dogs' behavior was taped for 6 min after the owner had fallen and was later scored for the frequency and time the dogs spent performing different behaviors. In no case did a dog solicit help from a bystander. It is concluded that dogs did not understand the nature of the emergency or the need to obtain help.     

Toward an animal model of type A behavior

Time estimation and dominance tests were used to differentiate the behavior of Mongolian gerbils to be analogous to Type A and Type B human behavior. Preliminary classification of animals as "Type A" or "B" was based upon differential performance on DRL 20-sec and DRL 60-sec reinforcement schedules. To retain their preliminary classification, Type A and Type B animals were required to be dominant and subordinate, respectively, in matches with each of three same-sex animals of opposite behavioral classification. Following classification, breeding pairs were constituted and classification procedures were repeated with two succeeding generations. Animals that exhibited Type A timing "won" significantly more dominance matches than did Type B animals. Incidence rates of Type A and Type B behavior in the two selectively bred generations were significantly greater than frequencies in the original stock generation. The usefulness of the present animal model for investigating the association of Type A behavior with coronary heart disease is discussed.     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress.

Changes in heart rate were examined during classical aversive conditioning before and after either left (n = 10) or right stellectomy (n = 8). Heart rate (HR) significantly (p less than 0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p less than 0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HC1 (BB, 1.0 mg/kg, n = 8), significantly (p less than 0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress

Changes in heart rate were examined during classical aversive conditioning before and after either left (n=10) or right stellectomy (n=8). Heart rate (HR) significantly (p<0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p<0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HCl (BB, 1.0 mg/kg, n=8), significantly (p<0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

Decreasing classroom misbehavior through the use of DRL schedules of reinforcement

In three studies, reinforcing low rates of responding reduced inappropriate behaviors. In the first study, the talking-out behavior of one TMR student was reduced when the teacher allowed 5 min of free time for a talk-out rate less than 0.06 per minute. In a second study, the talking-out behavior of an entire TMR class was reduced when reinforcement was delivered for a response rate less than 0.10 per minute. In a third study, successively decreasing DRL limits were used to reduce off-task verbalizations of an entire high school business class. In each case, the DRL procedure proved manageable for the teacher and successful in reducing misbehavior.     

Relationship between perceptual style and ability to reproduce a standard work task

The present study examined the relationship between perceptual style and perception of physical effort. Perceptual style of 10 men and 10 women was assessed by the rod-and-frame apparatus. Perception of physical effort was defined as the difference in heart-rate responses between a standard work task and the subject's self-selected task. Heart-rate response on the pre-selected standard work task on a cycle ergometer (600 kpm.min.-1) was extremely variable, ranging from 111 to 188 beats per minute (M = 153 +/- 23.5). However, average error between heart rate during the standard work task and the subjects' self-adjusted workload was extremely low (range 0 to 18 beats per minute; M = 5.4 +/- 5.5 beats per minute). Pearson correlation of .78 showed a moderate relationship between heart rate and rating of perceived effort, but was nonsignificant (-.12) between perceptual style and perception of physical effort. The data confirm the absence of a significant relationship between perceptual style (i.e., field dependence-independence) and ability to reproduce a standard work task. In addition, these results suggest that there has been possible bias in studies of relationships between heart rate and rating of perceived effort or workload and rating of perceived effort during incremental testing.     

Operant performance patterns of normal and nervous water-deprived dogs

Previous studies have shown that most food-deprived genetically nervous pointer dogs fail to learn a bar-pressing response for food reward and those which do learn are erratic in bar pressing compared to genetically normal pointer dogs which usually learn rapidly and perform well. Benzodiazepine drugs facilitate learning and performance of the responses in nervous dogs. The present study aimed at finding whether a stronger drive producing state, such as water deprivation, would facilitate learning and performance in even severely nervous dogs. Eight normal line and 7 nervous line dogs successfully learned to perform well a paddle-pressing response which activates a valve releasing water into a drinking pan. One disturbed dog of each line did not learn successfully. Behavior shaping was about as easy and as rapid in nervous line dogs as in normals. Nervous line dogs tended to be as consistent in responding. However, response rates of nervous line dogs averaged about two-thirds those of normal line dogs, the slowed rate of responses being taken up mostly in excessive, rather stereotyped, licking of the water pan. Response rates correlated well with degree of nervousness as measured on independent well standardized behavior tests. This behavior seems to add another dimension to the characterization of the nervousness of these “spooky” pointer dogs.     

Respiratory sinus arrhythmia in response to fear-relevant and fear-irrelevant stimuli

Heart period variability and heart rate were studied in 15 women and 15 men while they were viewing negatively (snakes/spiders), neutrally (scenic views), and positively (cats and kittens/puppies and dogs) valenced films. Time-frequency analyses of the heart period variability power spectrum in the high frequency region (0.12-0.4 Hz), reflecting respiratory sinus arrhythmia (RSA), were carried out during 5 minutes in each condition. The main finding showed that RSA-magnitude (high frequency power) was inversely related to emotional valence: lowest magnitudes were found in response to positive films, and highest magnitude to negative films. The findings were interpreted as reflecting motor or behavioral inhibition, and increased attention to negatively valenced, stimuli.     

Attrition and the Student Who is Certain

A study of 89 male students at a small liberal arts college tested the hypothesis that a student whose statement about vocational and/or academic goals expressed certainty and whose grade-point average was below a 2.00 at the end of one year would probably not graduate. The hypothesis had both statistical and practical significance since loss from this group was 75 per cent compared to an average loss of 37.1 per cent (Test of Proportions, z = 2.766, P = .0028).     

Effects of pentobarbital sodium anesthesia and neurohumoral agents on the cardiac orienting reflex

Studies of the cardiac orienting reflex in 16 dogs, moderately anesthetized and awake are reported. In the anesthetized dogs prominent transient heart rate decrease was commonly noted within one or two beats after the onset of various auditory stimuli, and less often after visual stimuli. This cardiac inhibition was neither as prominent nor as frequent in occurrence in awake dogs. The respiratory cycle at stimulus onset influenced the appearance and degree of heart rate decrease, with the greatest and most frequent decreases occurring during the expiratory phase. Atropine abolished the response. There was little evidence of habituation of this orienting response under anesthesia, although “waxing” and “waning” apparently related to minute-by-minute fluctuations in degree of unconsciousness, occurred. These findings are discussed in relation to neurophysiological and neuroanatomical correlates of orienting responses, hypotheses of orienting and attention and cardiovascular neurohumoral mediators.     

Evaluating the impact of adaptive signal control technology on driver stress and behavior using real-world experimental data

While the operational and crash reduction benefits of adaptive signal control technology (ASCT) have long been investigated, the impact of this technology on driver behavior and stress is still uncertain. This study evaluated the impact of ASCT on driver behavior and stress in a real-world environment. Participants travelled through two arterial corridors, one equipped with ASCT and the other having traditional time-of-day coordinated signals. Driver stress was measured using a heart rate detector and a perceived stress scale while driver behavior was examined using vehicular trajectory data. Overall, driving behavior improved on the ASCT as compared to the non-ASCT corridor, as indicated by higher speeds and a fewer number of stops on the ASCT corridor relative to the non-ASCT corridor. Repeated measures ANOVA showed a statistically significant reduction in driver heart rate by −10 beats per minute over the ASCT corridor. A similar trend was observed for drivers’ perceived stress, analyzed by Wilcoxon sign ranked test. Driving behavior also showed significant improvement with ASCT presence, and speed was found to be negatively correlated with stress. Furthermore, the participants’ speed was controlled by the two systems i.e. ASCT and non-ASCT as expected. This study provides a significant proof of concept that ASCT can create positive improvements in driver stress and behavior that can be further investigated in the future.     

Hypnotic pseudomemories,prehypnotic warnings,and the malleability of suggested memories

This study used Orne's nocturnal events paradigm to test the effects of warning highly hypnotizable participants about the possibility of hypnotic false memories. We found that warnings reduced suggestibility but not false memories during hypnosis. Fewer warned participants (12/32, 38 per cent) than unwarned participants (12/16, 75 per cent) accepted the suggestion to hear a noise that awakened them when they were age-regressed to a night of the previous week. However, an analysis of only those persons who accepted the suggestion during hypnosis showed that the warning had no effect on their posthypnotic pseudomemories: among this group, 75 per cent of warned versus 58 per cent of unwarned persons stated immediately after hypnosis that the noise occurred in reality (i.e., reported a pseudomemory). During a final confidential assessment, 58 per cent of the warned participants who had accepted the noise suggestion reported a pseudomemory, versus 50 per cent of the unwarned participants. Comparing pseudomemory rates across all participants, regardless of whether they passed or failed the noise suggestion, 28 per cent of warned participants versus 44 per cent of unwarned participants reported pseudomemories, a nonsignificant difference. Finally, warned and unwarned participants were equally confident in their false memories. © 1998 John Wiley & Sons, Ltd.     

Effect of person on nervous,stable and crossbred pointer dogs

Through selective mating and line breeding of pointer dogs we have developed and continued two strains which are fairly behaviorally distinct. We now have data accumulating from the crossing of these two lines. Although the offspring from the crosses are still young, it can be seen that some stable male parents have had nonenvironmental, i.e., genetic, effects. The offspring are in many respects like their nervous mothers, but in some behavior, notably social behavior, they can be mistaken for the stable strain of dog. Heart rates have mimicked those of the nervous mothers and seem in no way influenced by the stable ancestry in “Effect of Person” tests. There is a marked difference between stable and unstable dogs in the effect of “Person” on heart rate: the unstable dogs show practically no cardiac response to “Person” (petting), whereas the normal dogs show the usual marked bradycardia to petting.     

Metronome rate and walking foot contact time in young adults

It is assumed that when people walk guided by an audible constant rate, they match foot contact to the external pace. The purpose of this preliminary study was to test that assumption by examining the temporal relationship between audible signals generated by a metronome and foot contact time during gait. Ten healthy young women were tested in walking repetitions guided by metronome rates of 60, 110, and 150 beats/min. Metronome beats and foot contact times were collected in real time. The findings indicated that foot contact was not fully synchronized with the auditory signals; the shortest time interval between the metronome beat and foot contact time was at the prescribed rate of 60 beats/min., while the longest interval was at the rate of 150 beats/min. The correlation between left and right foot contact times was highest with the slowest rate and lowest with the fastest rate.