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.     

The heart rate component of the social reflex in dogs: The conditional effects of petting and person

Five dogs were given a 480-cps tone followed by shock for more than 200 trials. A 200-cps tone was then introduced followed by a person petting the dog at the end of the conditional signal (CS) for 50 trials. Finally, the 480-cps tone-shock (T-S) sequence was reintroduced for five trials, after which the person entered the experimental room and stood beside the dog during one additional T-S sequence. It was observed that both the heart rate (HR) increase to shock, and the HR decrease to petting could be conditioned rapidly (1–5 trials). These findings are discussed in terms of the theory of stimulus substitution in classical HR conditioning. After the person had been made part of a CS for petting, and the T-S sequence reintroduced, the HR increase during the CS was reduced. The HR response to the shock, however, was greater than the response to this US when the dog was alone. A control group, given the same T-S sequence with a person present who had not been a CS for petting, did not show any significant HR changes from the usual response given to the T-S sequence. It is emphasized that these findings, in conjunction with earlier reports, indicate that the cardiovascular system may be a valuable index in studying the psychophysiology of socialization processes.     

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.     

The role of gross locomotor restriction in the acquisition of motor and cardiac conditional discrimination in the dog

The effects of gross locomotor restriction and lack of restriction, respectively, on the acquisition of a motor and cardiac discrimination task was investigated. Litter-mate dogs were used in a counterbalanced design involving two treatment conditions (free and restrained) and two discrimination learning problems. Each learning problem included eight daily training sessions with 10 CS+ tones and ten CS—tones presented randomly. The US was a shock to the left foreleg. Degree of foot flexion and percentage change in heart rate in response to CS tones were recorded. Dogs subjected initially to the free condition manifested a superior and more rapid motor and cardiac discrimination than Ss initially restrained. The free condition was not as facilitatory when presented to Ss which first had been exposed to the restraint condition. The results are discussed in terms of activation and negative transfer.     

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.     

Biochemistry of nervous dogs

Previous behavioral studies on a nervous strain of pointer dogs have demonstrated genetic as well as environmental components in the nervous trait. Behaviorally these animals are extremely hypervigilant, with an apparent low threshold to fear and show strong avoidance of humans. In addition, the nervous E strain dogs show an unusually high degree of sensitivity to the mange mite. These observations led to the initiation of studies to determine whether differences exist between the normal A strain and the E strain of dogs at the biochemical level. Although a number of biochemical parameters examined have shown no statistically significant difference between the two strains, the modification of serum creatine phosphokinase (CPK) activity in response to various types of stress does differ as a function of strain—the nervous dogs being less, not more, responsive than the healthy dogs. When not specifically subjected to stress the serum CPK levels in both strains were highly related to age. Significant differences between strains also have been demonstrated in the cerebrospinal fluid acetyl cholinesterase activity levels in older animals. Tryptophan loading experiments, conducted in the presence and absence of the monoamine oxidase inhibitor, tranylcypromine, resulted in no readily observable behavioral modification of either strain and the response of the cerebrospinal fluid 5-hydroxyindoleacetic acid levels was similar for the two strains.     

One-trial cardiac conditioning in dogs

Our interest in cardiovascular conditioning, particularly the fact that conditional tachycardia has been observed in many dogs after only one or two combinations of conditional and unconditional stimuli, led us to investigate conditioning using a single application of an unconditional stimulus. Initially we studied the effect of orienting stimuli (soft tones) on the heart rate in 9 dogs. After 30–100 presentations of the tones alone, each dog received on one occasion a 25-volt shock (sufficient to cause yelping and struggling) to a leg as unconditional stimulus immediately following a tone. Thereafter 30–100 additional tones were presented with no further shock. Little or no heart rate change occurred during the orienting tones (before shock). Three types of cardiac changes occurred during experimental sessions after the shock: 1) Increased heart rate during the tones in 5 dogs; 2) Generalized lowering of heart rate during all experimental sessions after shock in 4 dogs; 3) Electrocardiographic changes during tones in 3 of the dogs also showing the generalized decrease in heart rate. No motor flexion conditional reflexes developed. Tones an octave different in pitch from the one associated with the shock also caused approximately the same heart rate changes, indicating lack of differentiation. This one-trial cardiac conditioning persisted after the single conditioning trial for more than a month in 2 dogs and for at least 3 to 5 sessions in the other dogs.     

Autonomic nervous control of heart rate orienting and alpha responses in dog

The object of this experiment is to study the autonomic nervous control of alpha responses elicited in classical conditioning. Twenty-two mongrel dogs were trained in classical discriminative conditioning. Typical two-phase tachycardic responses were observed in positive (CS+) trials while only the earliest, phase 1, response was observed in negative (CS-) trials. The phase 1 response, which was identical in CS+ and CS-trials, was compared in dogs before and after selective SA-nodal parasympathectomy (N=7) and beta-adrenergic blockade (N=11). The phase 1 tachycardic response was eliminated by selective SA-nodal parasympathectomy but not by beta-adrenergic blockade. We conclude that the phase 1 response observed in both CS+ and CS-trials with similar time sequence and magnitude is an alpha response. The heart rate orienting response results from a withdrawal of parasympathetic activity with little or no change in sympathetic tone.     

Correlations of normality and nervousness with cardiovascular functions in pointer dogs

Methylphenidate, 0.5 mg/kg, injected intravenously, was used in 10 normal (A line) and 10 genetically nervous (E line) dogs in a blind-design experiment to aid in prediction, from cardiovascular recordings alone, of behavioral normalityversus nervousness. The prediction was 75 per cent correct, based on heart rate (HR), form of the electrocardiogram (EKG), pattern of sinus arrhythmia, and pattern of HR response to methylphenidate. Nervous dogs were found to have slower baseline HR’s, delayed return of HR to baseline after methylphenidate, greater occurrence of baseline EKG abnormalities and much greater frequency of these after methylphenidate. Degree of nervousness was found to correlate rather highly (1)negatively with baseline HR level, (2)negatively with speed of BP response, and (3)positively with frequency of some of the EKG manifestations. These data, indicative of a relative inertness of physiological functions of nervous pointer dogs compared with normal pointers, are consistent with the behavioral and some of the biochemical findings previously reported.     

Crossbreeding and special handling of genetically nervous dogs

In studies of a healthy (A) and a nervous (E) genetic strain of pointer dogs, two techniques were utilized to determine environmental and hereditary influences. These were (1) reciprocal crossbreeding to females from each strain, and (2) split litters with special handling and human attention to one-half of each litter of nervous strain origin from birth through age six months. It is not possible to attribute the nervous behavior to an environmental mother effect since crossbred AE and EA offspring were highly similar on behavior tests of brief exploratory activity, rigid posturing to a loud noise and human avoidance behavior. Furthermore, special handling had almost no success in normalizing the responses of the nervous dogs in the behavior tests or in heart rate response to Effect-of-Person procedures. The results show that the biologic origin of the dogs is the most likely source of the nervousness; this has placed severe limits thus far on attempts to attenuate the condition.     

Psychogenic vagotonia in a family of beagle dogs

Eight inbred beagle dogs, litter mates of two generations, exhibited psychogenic vagotonia (long sinus pauses and transient atrioventricular block of the heart) during orienting to tones. This was intensified during tones following “one-trial conditioning” to a single painful leg-shock. It was potentiated during conditional stimuli (CS+) regularly reinforced by leg-shock; whereas unreinforced tones (CS?) elicited less vagotonia. Additional evidence of differentiation was observed in one dog when the differential magnitudes of the responses were reversed following reversal of the significance of the conditional stimuli. The possible mechanisms of these changes and correlations with clinical material are discussed. Results of this study illustrate the interplay between constitutional predisposition and psychological factors in prominent cardiovascular changes.     

Schizokinesis: Fragmentation of performance in two strains of pointer dogs

During the behavior shaping toward bar jumping to avoid shock at the termination of a tone, ten genetically nervous (“E”) and ten stable (“A”) dogs showed different performances in the acquisition of the adaptive motor response. When tested two months later and with concurrent monitoring of their electrocardiograms, these animals also showed differences in (1) baseline heart rate, (2) direction and degree of heart rate change to the conditioned tone stimulus (more often deceleration in the E dogs), and (3) response to the unconditioned shock stimulus. After having performed in an almost satisfactory manner for a few trials, thenervous animals often would suddenly freeze in rigid postures. These animals could frequently be made to emit the adaptive behavior by “breaking the frozen posture” through pushing, jumping, or pulling manipulation. Sometimes a forced righting reflex dramatically encouraged an integrated performance of varying duration. Thestable strain of dogs showed little or none of the rigidity and usually learned the smooth adaptive response. The stable A dogs showed retention of the cardiac Cr, but not of the motor Cr (which they re-formed after one or two reenforcements); the nervous E dogs also retained the cardiac Cr, but persisted in the maladaptive motor performance. The fragmented disorganized behavior in acquiring the adaptive motor act and thedifferential retention of the autonomic and motor responses are considered examples ofschizokinesis as conceptualized by Gantt. This schism is seen in clearer form in behavioral acquisition than in the usual frequency measure of the well-practiced act.     

The effect of Person on cardiac and motor responsivity to shock in dogs

Interaction between effect of social stimulus (Person) and a faradic shock on heart rate and motor response (leg flexion) in four dogs was observed and recorded. The trials during which the shock and petting were presented simultaneously showed a significant suppression of heart rate increase to shock when compared to the shock alone trials. The lack of this suppression effect in the motor response to the shock is discussed in relation to the concept of schizokinesis. The importance of controlling prior experience of subjects is also discussed.     

Rapid induction of specific associative behavioral memory by stimulation of the nucleus basalis in the rat

Hypothesized circuitry enabling behavioral memory formation can be tested by its direct activation in the absence of normal experience. Neuromodulation via the cortical release of acetylcholine by the nucleus basalis (NB) is hypothesized to be sufficient to induce specific, associative behavioral memory. Previously, we found that tone paired with stimulation of the nucleus basalis (NBs) for 3000 trials over 15 days induced such memory, supporting the hypothesis. However, as standard associative memory can be established much more rapidly, we asked whether NB-induced memory develops rapidly. Adult male Sprague-Dawley rats, trained and tested in the same calm, waking state, were divided into Paired (n=5) and control (n=4) groups, each of which received a single session of 200 trials of an 8.0 kHz conditioned stimulus (CS) either paired with NBs or with unpaired presentation of NBs. Respiration, cardiac activity, and evoked potentials in the primary auditory cortex (ACx) were recorded. Memory and its degree of specificity were assessed 24 h later by presenting tones of various frequencies (1-15 kHz) in the absence of NBs to yield behavioral frequency generalization gradients. Behavioral responses to test tones consisted of interruption of ongoing respiration and changes in heart rate. Post-training behavioral generalization gradients exhibited response peaks centered on the CS frequency for the Paired group alone. Tone evoked potentials from the ACx also developed CS-specific plasticity. The findings indicate that NB induction of specific behavioral associative memory, like normal memory, can develop rapidly and is accompanied by specific cortical plasticity, supporting the view that NB engagement during normal learning produces memory.     

Cardiac conditioning in the white rat with food presentation as unconditional stimulus

Pavlovian conditioning of heart rate in the white rat was attempted using milk presentation as reinforcement, and with both trace and delay paradigms. Delay conditioning produced positive results that were statistically significant, whereas trace conditioning exhibited the same trends but did not reach statistical significance. In both cases, CR had the same direction as UCR to milk (acceleration of heart rate) and opposite to the unconditional reaction to CS. Extinction and reconditioning were both accomplished. Some indications of complex response interactions were noted in the occurrence of the cardiac CR on conditioning trials where the instrumental response to the UCS (drinking) eventually occurred, as against the absence of cardiac CR on trials where the instrumental response did not occur. The existence of such interactions was also indicated by the fact that CR on individual trials within any single session could vary in direction between acceleration and deceleration, although averages might be stable.     

REDUCTION OF STATE-ANXIETY BY PETTING ANIMALS IN A CONTROLLED LABORATORY EXPERIMENT

The effect on anxiety of petting an animal and the underlying mechanisms of such an effect were examined by a repeated-measures, within-session experiment with 58 non-clinical participants. Participants were exposed to a stressful situation in the laboratory – the presence of a Tarantula spider, which they were told they might be asked to hold – and then randomly assigned to one of five groups: petting a rabbit, a turtle, a toy rabbit, a toy turtle or to a control group. Participants’ attitudes towards animals were measured as potential moderators. State-anxiety was assessed at baseline, after the stress manipulation, and after the experimental manipulation. The main findings showed that petting an animal reduced state-anxiety. This effect could not be attributed to the petting per se, since it was observed only with animals and not with matched toys. The anxiety-reducing effect of petting an animal applied to both the soft cuddly animals and the hard-shelled ones. The anxiety-reducing effect applied to people with different attitudes towards animals and was not restricted to animal lovers. The discussion addresses possible emotional and cognitive foundations of the observed effects and their implications.     

Cardiovascular generalization and differentiation: The relationship between heart rate and blood pressure

The present study was designed to study generalization and differentiation and to check the relation between heart rate and blood pressure in cardiovascular conditioning. Five naive mongrel dogs were presented with 10 sec 1000 cps tone regularly reinforced with 0.5-sec shock to a left foreleg. Four other 10-sec tones (600, 800, 1200, 1400 cps), never reinforced, were administered in a randomized and counterbalanced fashion using a differential reinforcing technique. The response measures were heart rate and three indices of blood pressure,i.e., systolic, diastolic, and pulse pressures.“Initial response” of heart rate showed rapid tachycardia to all tones, with no generalization and differentiation among five tones.“Terminal response” clearly indicated generalization gradients that tachycardia to 800 and 1200 cps tones were higher than those to 600 and 1400 cps tones, respectively. Some differences were noted among systolic, diastolic, and pulse pressures, with pulse pressure showing a trend of generalization and differentiation in the“initial response.” No statistical difference, however, was obtained in blood pressure scores. Beat-by-beat analyses of correlations between heart rate and diastolic blood pressure showed that the correlations successively decreased during the“terminal response.” Overall correlations between heart rate and three indices of blood pressure were obtained, with the highest correlation between heart rate and pulse pressure. Considering the above results in relation to the classical conditioning theory, it was tentatively concluded that“initial response” includes non-conditional factors, while“terminal response” reflects mainly a true conditional response, particularly, at a long CS-US interval. This interpretation leads to the hypothesis that conditional response with a short CS-US interval may attain better conditioning scores in terms of the summation effect between a non-conditional factor and a true conditional factor.     

Amphetamine effects on unconditional and conditional instrumental responses with alimentary and social rewards in dogs

The effect of amphetamine dose (0.5 mg per 1 kg) on conditional and unconditional responses based on alimentary and social motivation was investigated in two groups of dogs. Amphetamine resulted in a significant decrease of conditional instrumental responses (CRs) in both groups but did not attenuate significantly the dogs’ need for food or petting. On the contrary, the drug drastically increased the dogs’ need for petting, and its anorectic effect was mild. The deteriorating effect of amphetamine on mnemonic processes and its facilitatory effect on behaviors directed to get more than the usual amount of pleasant tactile stimulation might underlie the behavioral changes described in this study.     

Amphetamine increases intertrial but not conditional instrumental responding in the cortico-basomedial amygdalar dogs

The effect of partial cortico-basomedial amygdaloid lesions on dogs’ social behavior was investigated. The lesions did not affect the conditional instrumental responding (CRs) reinforced by petting or the dogs’ need for petting (US). The lesions increased the number of intertrial responses (ITRs) in all dogs. Subsequently the effect of low amphetamine doses (0.5 mg/l kg) administered intramuscularly to the amygdalar animals on the same behavioral parameters of the social behavior was examined. Amphetamine did not affect CRs but dramatically increased the ITRs and dogs’ need for petting. These findings suggest that the cortico-basomedial amygdaloid region may be involved in the cortical inhibitory mechanisms that are indispensable for promoting behavioral acts according to their usefulness and the situational context.     

Training of instrumental responses in dogs socially reinforced by humans

The motivational bases of the social reinforcement in human-dog relations were examined. In experiment I, performed on seven dogs, it was found that dogs were able to learn and sustain the natural responses of sitting, paw extension, and lying prostrate to conditional stimuli in the form of vocal commands reinforced only by social rewards given by the experimenter, such as petting and vocal encouragement. Overtraining did not produce deterioration of performance but, on the contrary, the continual decrease of latencies. It was evidenced that tactile stimulation plays an important role in social reward. In experiment II, instrumental responses to the auditory conditional stimuli were elaborated in two groups of dogs. The first group (nine dogs) was reinforced by food, and the second group (eight dogs) was reinforced exclusively by petting. A similar course of learning and level of performance during overtraining sessions in both groups indicated that petting serves as a good reinforcement, with rewarding value comparable to that of food reinforcement. It is suggested that a strong rewarding effect of pleasurable sensory stimuli occurs in the formation of the bond between dog and human and in the learning of different tasks.