ANTAGONISM OF A BEHAVIORAL EFFECT OF D-AMPHETAMINE BY CHLORPROMAZINE IN THE PIGEON

A dose of d-amphetamine which completely suppressed all responding was administered to each of five pigeons under an FR 30 schedule. When the pigeons were treated with chlorpromazine after 45 min or more, responding was restored. When d-amphetamine and chlorpromazine were administered simultaneously to three other pigeons, responding was better maintained than after d-amphetamine alone. This study confirms a previous finding that chlorpromazine can antagonize the rate-decreasing effect of d-amphetamine.

OPERANT CONTROL OF PREENING IN PIGEONS

Preening in four pigeons was observed and recorded during operant level determinations, continuous and variable interval reinforcement, and extinction. The rate at which preening responses occur seems to be controlled by reinforcement in the same way as other operant behavior. Preening during VI reinforcement and extinction appeared to be similar to preening in many natural situations. With respect to the part of the body preened, considerable stereotypy of responding was shown by all birds, particularly during VI training; there was, however, a conspicuous absence of consistency in the development of stereotypy both within and between individual birds, perhaps due to the nature of the response.

PERSISTENT BEHAVIOR MAINTAINED BY UNAVOIDABLE SHOCKS

Squirrel monkeys were trained on a multiple schedule in which 10-min periods on a continuous shock avoidance schedule, indicated by a yellow light, alternated with 10-min periods on a 1.5-min variable interval schedule of food reinforcement (VI 1.5). A white light indicated that VI 1.5 was in effect, except for the middle 2 min of the period on VI 1.5, in which a blue light appeared and terminated with the delivery of a 0.5-sec unavoidable shock. Stable response rates developed in the avoidance and VI 1.5 components. However, the highest response rates occurred in the blue, preshock stimulus. A series of experiments showed that responding in the blue stimulus persisted even when responding had been extinguished on both the VI schedule of food reinforcement and the shock avoidance schedule. Responding in the blue stimulus ceased when the blue stimulus terminated without shock or when it terminated with a response-contingent shock. Each time responding ceased, it was restored by terminating the blue stimulus with an unavoidable shock. When the blue stimulus was on throughout each session and unavoidable shocks were delivered at regular 10-min intervals, responding was well maintained. These results show that in monkeys that have been trained on a continuous avoidance schedule, unavoidable shocks can maintain responding even under conditions where responses have no programmed consequences.

MUTUAL POTENTIATION OF AMPHETAMINE AND AMYLOBARBITONE MEASURED BY ACTIVITY IN RATS

Dose/response relations have been analysed for the actions of amphetamine-barbiturate mixtures on exploratory activity and ataxia in rats. Amphetamine sulphate and amylobarbitone sodium were studied separately and together (in a constant ratio of 1:20) in doses which ranged from those producing no effect to those which incapacitated the animals. Dexamphetamine and amylobarbitone were similarly studied in a ratio of 1:6.5; this corresponds to the ratio of a commercial preparation, Drinamyl. The results showed that mixtures could stimulate exploratory activity and their maximal effects were much greater than the effects produced by any dose of the separate drugs. The maximal effect with the first dose-ratio included conspicuous ataxia, but the maximal effect with the second ratio did not. Further experiments in which the dose of one drug was held constant and that of the other was varied showed that maximal effects on activity could be obtained with mixtures of dexamphetamine and amylobarbitone. Equivalent effects could be obtained both with relatively small and with relatively large amounts of the two drugs, in varying ratios; some constituent doses of the individual drugs were found to be optimal; whether the mixture effect was accompanied by ataxia depended largely on the constituent amount of barbiturate. For practical purposes mixtures producing maximal effects on activity with the smallest amounts of both drugs and not accompanied by ataxia might be most desirable, and these can be approximately read off from an isobol plotted from the results. It was concluded that the marked stimulant effects of the amphetamine-barbiturate mixtures on activity of rats could be regarded as due to true potentiation.

OVERT "MEDIATING" BEHAVIOR DURING TEMPORALLY SPACED RESPONDING

A rat was trained on a schedule that programmed reinforcements only when a minimum waiting time between successive responses was exceeded (DRL schedule). It was observed to fill much of the pause between lever presses with a stereotyped behavioral chain: it would take its tail in its mouth and nibble it. This behavior was shown to be functionally related to the efficiency with which the subject spaced its responses. It is thought to have served as mediating behavior, providing discriminating stimuli for appropriate lever presses.

A NOTE ON BEHAVIORAL TOLERANCE TO MEPROBAMATE

Behavioral tolerance to meprobamate was demonstrated in a cat, on an FI schedule, without behavior taking place during the chronic treatment. Behavioral factors, such as the development of corrective patterns of behavior, do not explain behavioral tolerance in this case.

EFFECTS OF EARLY ENVIRONMENTAL COMPLEXITY ON THE FOLLOWING RESPONSE IN CHICKS

Six groups, each consisting of 7 Vantress Broiler chicks, were reared in a complex environment, rich in sensory stimulation, from hatching until imprinting 3, 6, 9, 12, 15, or 18 hr. later. Another six groups of 7 each were reared in a restricted environment and imprinted at the same times. The strength of the following response was tested for all animals between 36 and 48 hr. after imprinting. The response of the chicks reared in the complex environment was distinctly stronger over the entire range. In addition, the “critical period” for these animals occurred earlier.

MOTOR OUTPUT PATTERNS DURING RANDOM AND RHYTHMIC STIMULATION OF LOCUST THORACIC GANGLIA

This paper employs new statistical techniques to further analyze the flight control system of grasshoppers. The quantitative results confirm some hypotheses which arise from previous studies of this system. After decapitation and ablation of wing proprioceptors, stimulation of the nerve cord at random intervals can elicit a coordinated response closely resembling the normal flight motor output pattern. The coordinated response begins only after many stimuli and there are usually many cycles of after-discharge. The frequency of the cyclic output is rather low and may be increased only slightly by large increases in stimulus frequency. Input from the stretch receptors is necessary to attain normal wingstroke frequency. Frequency of wingbeat rises with a time constant of about 2 seconds (or about 25 wingbeats) when stretch receptor stimulation is initiated. Frequency decay after cessation of stimulation has about the same time constant. No special phase relationship between stimulation and output is necessary for the increase in frequency or maintenance of normal pattern. When input frequency is adjusted as closely as possible to output frequency it is still not possible to force the output to maintain a particular phase with respect to the stimulation, all phase relationships still occur. In some animals all phases occurred with equal probability; in others a particular phase was preferred. When there was a strong phase preference the normal output pattern was disrupted.

POSTURAL STABILITY IN THE DOG

Positional stability in quietly standing dogs has been evaluated in terms of force records from individual feet and the position of the center of gravity. All four dogs carried approximately 60% of their total weight on their anterior feet and roughly 50% of their weight on each side. Within-trial variations from the mean of the fraction of total weight borne on any one foot ranged from 0.3 to 4.5% with a mean of 1.4%; between-trial variability ranged from 1.1 to 2.7%. Continuous movement of the center of gravity occurred within an area measuring approximately 1.5 cm on a side. Shifts in weight distribution within and between trials occurred in a variety of patterns which could be described in terms of the behavior of pairs of transverse, longitudinal, and diagonal couples. Preliminary observations of the reactions to a sudden disturbance confirm the hypothesis that quiet stance is accomplished through central nervous regulation. It is concluded that the trained dog behaves with a sufficient level of predictability to permit its use as a subject in a further examination of the postural control system.

EFFECT OF ILLUMINATION AND D-AMPHETAMINE ON THE ACTIVITY OF THE RHESUS MACAQUE

The activity of the Rhesus macaque was measured under three levels of ambient illumination and three dosages of d-amphetamine. Analysis of variance indicated that activity increases as a function of increasing level of illumination and decreases as a function of increasing dosages of amphetamine. The interaction effect was nonsignificant.

BEHAVIORAL-NEUROCHEMICAL CORRELATION IN REACTIVE AND NONREACTIVE STRAINS OF RATS

Male and female rats of the Maudsley reactive and Maudsley nonreactive strains were tested in the open-field to obtain ambulation and defecation scores. They were later killed, and their brains were dissected into five portions and analyzed for serotonin. Males defecated more and ambulated less than females, and nonreactive males ambulated more and defecated less than reactive males. These behavioral differences were significant (p .05). A statistically significant difference was found for the amounts of serotonin in specific regions of the brain between males and females (males higher) and between reactive and nonreactive males (reactive higher). Significant negative correlations between serotonin values in specific regions of brain and ambulation scores were found in these animals viewed as a group or even within a given strain and sex.

SOME PHARMACOLOGICAL EFFECTS OF A SERIES OF TRYPTAMINE DERIVATIVES

The methods of synthesis and some pharmacological properties of a number of N-substituted tryptamines are described. Peripheral vasopressor activity decreased with increase in complexity of the substituent and was not related to toxicity or to behavioural activity. Activity in increasing the rectal temperature of rabbits appeared to parallel modifications in the open-field behaviour of rats. Some compounds were investigated for their ability to block a conditioned avoidance-response in rats and to affect operant conditioning in cats. Evidence is presented which suggests that the tryptamine derivatives are metabolized in vivo to more active forms.

LABORATORY CONTROL OF TOE-SUCKING IN A YOUNG RHESUS MONKEY BY TWO KINDS OF PUNISHMENT

Both response-contingent withdrawal of a visual reinforcement and response-contingent presentation of an aversive stimulus (loud noise) were found to be effective in suppressing toe-sucking in a young rhesus monkey.

BEHAVIOR STABILITY AND RESPONSE RATE AS FUNCTIONS OF REINFORCEMENT PROBABILITY ON "RANDOM RATIO" SCHEDULES

A random ratio schedule is one under which every ordinally specified response has the same probability of reinforcement as any other. Data have been gathered at several values of this type of schedule, using a separate group of pigeons for each schedule value and giving prolonged exposure to each value. No simple relationship was found between response rate and reinforcement probability. In general aspect group data from the present experiment agree with those from a single organism study cited. It was shown that 40 to 50 days of exposure to random ratio schedules yields fairly asymptotic response rate data. The tabulated raw data, and the results of some statistical manipulations, have been deposited with the American Documentation Institute.

PROBABILITY-LEARNING BY THE TURTLE

Tested in a two-choice situation, the painted turtle, Chrysemys picta picta, shows random probability-matching in visual problems and in confounded visual-spatial problems, but only maximizing or nonrandom matching (reward-following) in spatial problems. The results are compared with those of analogous experiments on fish, bird, and mammal.

SEQUENTIAL BEHAVIOR INDUCED REPEATEDLY BY STIMULATION OF THE RED NUCLEUS IN FREE MONKEYS

Rhesus monkeys in a colony were stimulated by means of intracerebral electrodes controlled by radio, for 5 seconds every minute, day and night, for periods up to 14 days. Stimulations of the red nucleus evoked a reliable sequence of behavior including bipedal locomotion, climbing, vocalization, and social interactions. During periods of spontaneous sleep, stimulations produced only a small head movement, but the whole behavioral sequence reappeared as soon as the animal awoke. In monkeys injected with chlorpromazine, the evoked behavior was inhibited in the same way as during spontaneous sleep, while the administration of atropine, Regitine, and Indurol which blocked both sympathetic and parasympathetic systems, produced only minor modifications of the sequential response.

SELF-PRESENTATION AND SELF-TERMINATION OF A CONFLICT-PRODUCING STIMULUS

Rats could press a lever to initiate or terminate a stimulus that was associated with intermittent rewards and punishments. Subjects spent time in both the stimulus-on and stimulus-off condition and oscillated frequently between the two conditions. This method provides continuous, quantitative records of oscillatory behavior and is sensitive to manipulations of shock intensity and food deprivation as well as the relative frequency of reward and punishment.

ILLUMINATION PREFERENCE OF ALBINO RATS IN A CLOSED HEXAGONAL MAZE

Ss were allowed to choose among 6 illumination conditions by altering their location in a maze. For a choice among 0 (darkness), 1, 2, 4, 8, and 16 ft.-candles in Exp. 1, preference decreased with increasing intensities. Ss tested during the dark portion of their cycle showed a stronger preference for darkness than Ss tested during the lighted portion of their cycle. In Exp. 2, preference for 0, .01, .1, 1.0, 10.0, and 25.0 ft.-candles was again inversely related to intensity, except that there was no difference between preference for darkness and .01 ft.-candles.