Oddist D. Murphree

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 rehabilitation of genetically nervous dogs

Aware that intensive efforts to rehabilitate half of split litters from a nervous strain of Pointers through daily human contact have been unsuccessful, the authors designed this study to determine if a radically different approach utilizing the natural interest for birds and hunting which most Pointers possess would be a bridge to normalcy so that dogs genetically prone to nervous behavior could be rehabilitated.Five nervous and three normal dogs approaching young adulthood were gradually desensitized to open areas, live quail, gun reports and humans—all of which usually produce catatonic freezing, hyper-startle and strong avoidance behavior in the nervous animals. Through a “naturalistic” approach in the framework of the Pointers’ non-laboratory ecological niche using graduated techniques, reciprocally competitive responses and social facilitation, which are described, all the nervous dogs that showed an original “interest” for the qua.l were trained as successful hunted dogs, not obviously different in final performance from their normal kennel mates. Although the nervous dogs overcame their freezing, hyper-startle and human aversion while hunting, generalization did not extend sufficiently to normalize standard behavior test scores obtained under laboratory conditions. These remained at their prerehabilitation level, raising the question of the adequacy of the behavioi tests conducted in a laboratory environment. This appears to be related to the limitations often seen in psychotherapeutic efforts.

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.

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.

Psychopharmacologic facilitation of operant conditioning of genetically nervous catahoula and Pointer dogs

Previous work has demonstrated that a genetic factor underlies much of the disturbed behavior in one strain of short haired pointer bird dogs (E line) maintained for several years in our laboratory. In some dogs the behavior is seemingly permanent and is characterized by human avoidance, excessive startle, reduced exploratory activity, and “freezing” or catatonic posturing. Another strain of dogs, catahoulas, with a high incidence of disturbed behavior similar to that above but with much less catatonic posturing, was made available for study also. In both of these strains defensive reaction and gross avoidance behavior often prevents the acquisition and later performance of operant conditioning (bar pressing for food reward) unless supportive tranquilizing chemotherapy is given.The chief interest in this study is, (1) the nearly permanent disharmony in the animal which seems to be an example of Gantt’s concept of schizokinesis, and (2) a comparison of 12 psychoactive compounds widely used in psychiatry for their effectiveness in restoring integrated adaptive functioning even in the most disturbed of the animals in our colony. The results show that: 1. even dogs with the most severe schizokinetic disabilities of many years duration have learned the operant conditioning (bar pressing); 2. however, it was and has remained necessary to facilitate both behavior shaping and nearly all later performances throughout the following year with benzodiazepine tranquilizers and these were far superior to any of the several other drugs tested; 3. neither gradual or rapid withdrawal nor sudden stopping of benzodiazepines allowed the dogs to continue the bar pressing. In fact, during withdrawal of the drug, performance seemed to parallel blood levels as reported in the literature.

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.

Procedure for operant conditioning of the dog

Most reports arising from operant conditioning procedures have little or no emphasis on the actual behavior shaping or acquisition phase of the responses which are the cumulative frequency of the well-practiced act. There is a need for more detail for beginners or those desiring a clearer understanding of procedures leading to the finally reported data. The procedure reported here is typically used to compare animal subjects or conditions, such as drugs, both in the acquisition and final phases of behavior.Beginning with an unconditional response (e.g. feeding) a bridging stimulus is paired in classical conditioning fashion. From that point on the bridging stimulus and UCS (feeding—or shock) are used immediately as reward or reinforcement only for responses “in the direction of the final desired behavior. The number of timed standardized behavior shaping sessions to criterion is the best index of acquisition phase performance and the total number bar presses or the rate of bar pressing (slope) is the usual index of operant responding. With timid animals it is often necessary to administer tranquilizers.

An inexpensive activity measuring device for small animals

A satisfactory device for measuring activity of rats or other small animals has been a difficult problem. Several types of instruments have given incorrect measurements or are prohibitively expensive. Photocells give the same readout to a bobbing head as for a walk over a considerable distance requiring only the interruption of a light beam. Other devices require rotation of wheels or complex integrating circuits which must be replicated or scanned and recorded for simultaneous activity measurement of many animals.The device reported here utilizes the tilting of balanced cages to actuate a single microswitch coupled to an impulse counter for each cage. The system has functioned well for several years.

Reduction of anxiety in genetically timid dogs

In behavior studies of genetically timid and normal dogs it was possible to focus on nervous non-performing animals in a search for agents which might attenuate the overriding anxiety which causes these animals to become rigid, aversive-avoiding or bizarre in the presence of humans. Of the drugs tested, chlordiazepoxide (Librium, Roche), 75 to 200 mg per dog per day, was most effective in alleviating the anxious condition. Sometimes the drug had the effect of getting the animal over a “threshold” so that he continued to perform (bar-pressing) indefinitely after once started through the aid of chlordiazepoxide. This is considered an example of both schizokinesis and autokinesis which Gantt first described and associated with drug action utilizing conditional response techniques.

Sporadic transient atrioventricular block and slow heart rate in nervous pointer dogs

Two behaviorally distinct strains of pointer dogs, one bred for nervousness (pronounced freezing behavior, withdrawal behavior), the other bred for normal behavior, exhibit prominent differences in their heart rates and incidence of sporadic occurrences of atrioventricular heart block. Of 67 nervous-line dogs, 70 per cent showed second degree AV-block on at least one occasion, and their heart rates averaged 65 beats/min. Only 15 per cent of 52 normal-line dogs displayed AV-block (generally fewer instances per dog) and their heart rates averaged 110 beats/min. Fifth generation nervous-line puppies, two to six weeks old, exhibited occasional AV-block even at heart rates averaging 183 beats/min. The incidence and “severity” increased as the puppies aged. Dogs crossbred from second and third generation parents of the two main lines show intermediate incidences of AV-block and intermediate heart rates. The incidence of AV-block is predominant in females. This is interpreted as a sex-influenced, agedependent, polygenic mode of inheritance. Humoral factors probably account for the sex-influence, and psychological stress probably also plays a role. No sex difference is noted in heart rates.