Biomedical subjects
J V BRADY
Publications and source records attributed to J V BRADY.
FACILITATION OF LARGE RATIO PERFORMANCE BY USE OF CONDITIONED REINFORCEMENT.
Fixed ratio performance was examined in the chimpanzee under two alternating conditions. In one, conditioned reinforcement followed successive fractions of the total ratio, and in the other it was omitted. Shorter pauses and working times, and the development of a strong preference resulted for the condition affording conditioned reinforcement.
BEHAVIORAL STRESS AND PHYSIOLOGICAL CHANGE; A COMPARATIVE APPROACH TO THE EXPERIMENTAL ANALYSIS OF SOME PSYCHOSOMATIC PROBLEMS.
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TIMING BEHAVIOR AND CONDITIONED FEAR.
Rats were trained on a two-response timing procedure which required that response B follow response A by at least a minimum specified interval in order to be reinforced with food. Repeated presentation (5 min on, 5 min off) of an auditory warning stimulus terminated by a brief electric shock to the feet (conditioned fear) produced a marked suppression in the frequency of A-to-B response sequences during the warning stimulus. The distribution of A-to-B interresponse times (timing behavior), however, did not change during the warning stimulus.
Heart rate: differential effects of hypothalamic and septal self-stimulation.
Heart rate in rats was recorded during self-stimulation with electrodes permanently implanted in both the hypothalamus and the septal region. Acceleration was observed during stimulation of the hypothalamus, and deceleration during stimulation of the septal region. In both areas self-stimulation reduced variability in heart rate.
Concurrent measurement of heart rate and instrumental avoidance behavior in the Rhesus monkey.
A graphical method has been developed for the concurrent recording of heart beats and lever responses during behavioral experiments. The EKG signal fed into any DC amplifier goes to a fixed level trigger circuit and relay driver with its own power supply. The signal from this drives any standard cumulative recorder. Lever response rates are recorded concurrently on an additional cumulative recorder using the same paper speed.
Drug effects on lever positioning behavior.
A technique is described for generating a continuous lever positioning response in the rhesus monkey. The effects of several drugs on this behavior were studied.
Quantitative relations between avoidance behavior and pituitary-adrenal cortical activity.
The rate at which monkeys pressed a lever and avoided shocks was manipulated in several ways. Measurements were also made of their plasma levels of 17-hydroxycorticosteroids. The rate at which the animals pressed the lever and the frequency with which they received shocks were both implicated as determiners of the steroid levels.
Electroencephalographic correlates of temporally spaced responding and avoidance behavior.
This study was undertaken to determine whether any EEG changes occurred during a multiple schedule of reinforcement consisting of repeated periods of avoidance behavior, a time-out (TO) period, and a period of differential reinforcement of low rates (DRL). The two monkeys were permanently implanted with bipolar electrodes in various subcortical areas. The EEG was recorded from these electrodes for several weeks before any behavioral training was undertaken. Training was then begun in the multiple schedule, and EEG recordings were taken frequently throughout the training period. When a stable performance level was achieved, drugs (dl-amphetamine and sodium pentobarbital) were introduced which disrupted the DRL performance but had little or no effect on avoidance behavior. The EEG recordings continued throughout these drug studies. The data indicate that the marked behavioral differences noted in each component of the schedule were not reflected in the EEG. However, the EEG did correlate with the general level of alertness of the animals during the various components. The drugs which differentially affected the behavior in the components of the schedule did not differentially affect the EEG, but they did change the brain-wave activity equally in all components. Finally, EEG changes correlated with the complex motor response of lever pressing were not observed.
Complex response patterns during temporally spaced responding.
A series of experiments is reported in which two monkeys emitted complex response patterns, not specified by the experimental program, during the DRL component of a multiple schedule. Administration of sodium pentobarbital and dl-amphetamine, drugs which disrupted the DRL performance, were also observed to suppress these collateral responses. Sequences of these collateral responses appear to mediate, at least in part, the timing process required for reinforced performance on the DRL schedule.
Gastric contents and the occurrence of duodenal lesions in the rhesus monkey during avoidance behavior.
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Instrumental conditioning of jugular self-infusion in the rhesus monkey.
A technique is described for self-infusion of pharmacologic agents in solution through a permanently indwelling jugular catheter in the rhesus monkey. The results of an experiment utilizing this technique demonstrate that an instrumental lever response can be conditioned, extinguished, reconditioned, and brought under stimulus control and reward-schedule control with saline self-infusion as the reinforcing stimulus.
Patterns of corticosteroid and pepsinogen change related to emotional stress in the monkey.
In association with conditioned avoidance sessions of 72 hours' duration, monkeys showed a response pattern characterized by increased levels of 17-hydroxy-corticosteroids and decreased levels of pepsinogen during the stress period, with a marked and prolonged elevation of pepsinogen levels occurring during the recovery period.
Effect of electroconvulsive shock on an extinguished "fear" response.
To test Gellhorn's hypothesis that electroconvulsive shock reinstates extinguished responses, a conditioned "anxiety" response was established and then extinguished in rats. A series of treatments did not restore the extinguished "anxiety" response; in fact, control animals showed appreciable spontaneous recovery of the "anxiety" response while treated animals did not.
The role of limbic system structures in the regulation of ACTH secretion.
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Some effects of limbic system selfstimulation upon conditioned emotional behavior.
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Some effects of brain stimulation on timing behavior.
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Animal experimental evaluation of drug effects upon behavior.
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