Behavior and physiology of the monkey (Macaca mulatta) following 2500 rads of pulsed mixed gamma-neutron radiation.

v I, Introduction 1 II. Materials and Methods 1 III. Results 4 IV. Discussion 11 References 14 LIST OF FIGURES Figure 1. Behavior and physiology following irradiation 6 Figure 2. Behavior and physiology following irradiation 6 Figures. Behavior and physiology following irradiation 7 Figure 4. Behavior and physiology following irradiation 7 Figure 5. Behavior and physiology following irradiation 8 Figure 6. Behavior and physiology following irradiation 8 Figure 7. Mean values for behavior and physiology of six monkeys irradiated with 2500 rads midline tissue dose of mixed gamma-neutron radiation 10 TABLE Table I. Aortic Pressure at the Beginning and End of the Early Performance Decrement Period 9 FOREWORD (Nontechnical summary) In the present study, monkeys were trained to perform a shock motivated visual discrimination task. These monkeys were then surgically implanted to monitor aortic and venous pressures, carotid flow, heart rate and respiratory rate. These physiological indices were monitored before and following irradiation to evaluate the effects of physiological changes on the monkey's ability to perform a learned task. Five of six animals showed a performance decrement (less than 90 percent correct responses) within the first 10 trials (1. 67 minutes) of the first 100-trial session (16. 7 minutes) following irradiation. One animal displayed no decrement in performance during this first session. All of the animals except one performed at an acceptable level (above 90 percent correct responses) after the performance decrement during the first session. Five of the animals showed a second decrease in performance between 40 and 45 minutes postirradiation. The performance of four animals returned to an acceptable level following this secondary performance decrement. The aortic pressure was severely decreased in five of six animals from approximately 8 to 20 minutes postirradiation. The first physiological indication of the ensuing incapacitation was an increase in pulse pressure caused by a rapid decrease in diastolic pressure quickly followed by a decrease in systolic pressure. Performance was not adversely affected until the diastolic pressure decreased to approximately 35 mm Hg. The systolic pressure varied considerably at this time