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Electrical properties of shock "punishment" delivered from implanted electrodes were studied . Subjects were six male albino rats, with four of the subjects under nembutal anesthesia and two not anesthetized. In addition, measures were taken at various times after electrode implantation so as to observe the effect, if any, of age of implant. Impedance characteristics at high and low voltages show that the rat is not a simple resistor. Anesthesia is not an important variable but age of implant seems important at low voltages. Problem Impedance measurements are reported for six male Sprague-Dawley white rats-(6-9 months old) a s a function of impressed voltage, using chronic body electrode implants . Although previous studies with rats have utilized implanted electrodes (e. g., Feirstein & Miller, 1963; Hendry & Hendry, 1963), they have not explored systematically the impedance characteristics of the organism. This has been done in the pigeon by Sidley and Schoenfeld (1963). MethodElectrodes of #30 gauge teflon coated silver wire were implanted subcutaneously in the right shoulders of the rats. The electrodes were about 3/8 in apart, and were formed by twisting together two strands of insulated wire and cutting the tips so that the exposed electrode areas consisted only of the cross-sections of the two wires. Separation of the tips was maintained by fixing them with a drop of dental acrylic cement. The electrode wires were led subcutaneously to a connector socket mounted on the skull. The socket was connected by external cable to the shock source. A shielded transformer supplied 60 cycleAC across a precision 10K ohm resistor in series with both the animal and a 1K ohm precision resistor. Applied voltage was calibrated on an oscilloscope, and voltage drop across the 1K ohm resistor was read from the oscilloscope. Impedances were calculated by Ohm's law.Eight voltages (all given in root mean square) were used: 1. 38,2.76,5.53,11.04,22 .09,44.19,88.38,176.75. At each voltage the rats were given a train of ten 60-millesec. pulses at a rate of 1 pulse per sec. Measurements were made first in an ascending, then a descending, series of voltage magnitudes. Approximately 90 sec. of "rest" separated both series and voltage values.Initial measurements were made on 4 animals under nembutal anesthesia (Rats 20, 21, 22, and 23) and on 2 non-anesthetized animals (Rats 24 and 25). The drug Psychon. Sci., 1964, Vol. 1. dosages, which included chloral hydrate supplements, were those recommended by Val en stein (1961). These first measurements were made on the several animals at varying times after implantation: Rat 20, 32 days; Rat 21, 5 days; Rat 22, 18 days; Rat 23, 20 days; Rat 24, 4 days; Rat 25, 4 days. Redeterminations were then made after the initial measurements as follows: Rat 20, 11 days (thus making a total of 43 days after implantation); Rat 21, 26 days (31 days after implantation); Rat 22, 20 days (38 days after implantation); Rat 23, 18 days (38 days after implantation); Rat 24, 9 days (13 days after implan...

After initial regular reinforcement of a lever-pressing response with milk, 6 groups of food-deprived rats were exposed to a concurrent random ratio punishment procedure wherein each group continued to be rewarded but had a different probability of receiving a brief electric foot shock for each response. Response suppression increased with punishment probability, with marked drop in responding at the highest shock probabilities. After 22 hr. of exposure to these "conflict" schedules, autopsies revealed (a) that adrenal and thymus weights had decreased under intermediate levels of punishment probability, and (b) that no gastric ulceration occurred in any S. A second experiment confirmed these findings and also traced the time course of these effects.