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Biomedical subjects

R R Hutchinson

Publications and source records attributed to R R Hutchinson.

At least 19 recordsLinked to original sources
PubMed1986

Brief exposure to contingent reinforcement produces a sustained increment in the strength of an elicited response.

Squirrel monkeys' lever pressing produced by response-independent shock was measured before, and for an extended period following, exposure to a shock-avoidance procedure. Following avoidance training, the frequency of responding increased by multiples of 10 to 50 across subjects and evidence little or no decrement for up to 6 months of postreinforcement testing. Manual responding produced by intense environmental stimulation may be substantially strengthened by a brief history of reinforcement, such that it is sustained over long periods without reinforcement.

Animals↗
PubMed1983

Discriminated instrumental learning by an acute encéphale isolé preparation.

Rats were prepared and maintained with high cervical transections in order to study learning in an intact brain that is isolated from uncontrolled sensory input and immobilized, allowing ready access to central physiological mechanisms. Stimulation electrodes were aimed at loci associated with response reinforcing processes. A response sensor was placed in the mouth to record both learned and evoked biting. All experimental subjects were trained successfully to discriminate the presence of an exteroceptive stimulus that indicated availability of the brain stimulation for biting. An intact control subject performed similarly in a lever pressing situation for brain stimulation. Biting also was evoked in both experimental and control subjects following removal of reinforcers, in a relation like that previously demonstrated between withdrawal of reinforcers and attack. The value of the experimental procedure in the study of the neural bases of learning and of the interactions between learned and inherent response processes is discussed.

Aggression↗
PubMed1983

Unique influences of ten drugs upon post-shock biting attack and pre-shock manual responding.

Delivery of a fixed-time, response-independent electric tail shock to the squirrel monkey generated bites on a rubber hose immediately following shock and manual responses on a lever immediately preceding shock; two temporally and topographically different responses in a single organism in a single experimental session. d-Amphetamine, cocaine, and caffeine each had the effect of elevating both bite and lever press responses; nicotine, chlorpromazine, chlordiazepoxide, and diazepam each elevated lever press responding while depressing bite responding across a portion of the dosage range; phenobarbital, alcohol, and morphine had the effect of depressing both bite and lever press responses but lever pressing was selectively more depressed than biting. The results parallel previous research with these drugs on other measures of aggression and on other behavioral paradigms. The responses are contingency free so that the effect of a drug does not interact with response produced environmental consequences. The recording of two separate responses related to distinct emotional states from one organism in a single experimental session allows for the objective measurement of selective and differential drug effects.

Aggression↗
PubMed1983

Effects of phencyclidine on aggressive behavior in squirrel monkeys.

Effects of phencyclidine (PCP) on shock-induced and spontaneous aggression in the squirrel monkey were determined. The delivery of response-independent, fixed-time (4', S-S interval) electric shock to the tail of a restrained squirrel monkey generated post-shock, hose-bite attack responses and pre-shock lever press non-attack responses. In a separate procedure shock was not delivered and spontaneous aggression responses were measured. A PCP dose response function (0.01-1.0 mg/kg SC) was determined for each procedure. In the shock-induced aggression procedure initial increases in attack were observed but upon a second determination of the dose effect curve this effect decreased and an increase in non-attack was noted. PCP produced increases in non-attack responding at high dosages in the spontaneous aggression procedure.

Aggression↗
PubMed1978

Possible errors in identification of squirrel monkeys (Saimiri sciureus) from different South American points of export.

We conducted karyological studies on one colony consisting of 12 Colombian and 34 Bolivian squirrel monkeys and a second colony of 47 monkeys imported into the United States between 1968 and 1974 through six importers. All animals in the first colony showed six acrocentric pairs of chromosomes. Bolivian monkeys were phenotypically distinguishable by their large size and coloration. In the second colony, 19 Peruvian, seven Colombian, five Bolivian and six Guyanan monkeys were correctly identified phenotypically and had five, six, six, and seven acrocentric pairs of chromosomes, respectively. Among Peruvian monkeys, 34.5% of the phenotypic classifications were in error.

Animals↗
PubMed1977

Electric shock produced drinking in the squirrel monkey.

Squirrel monkeys were periodically exposed to brief electric tail shocks in a test environment containing a rubber hose, response lever, and a water spout. Shock delivery produced preshock lever pressing and postshock hose biting. Additionally, all subjects displayed licking responses following postshock biting-attack episodes. Further experiments showed that licking was: (1) influenced by hours of water deprivation; (2) drinking behavior; (3) the direct result of shock delivery; and (4) developed spontaneously in naive subjects with or without opportunities for hose biting or lever pressing. Removing the opportunity to attack increased postshock drinking. A noxious environmental stimulus that causes aggression can also produce drinking.

Aggression↗
PubMed1971

Effects of long-term shock and associated stimuli on aggressive and manual responses.

Squirrel monkeys were exposed to response-independent, fixed-frequency shock that produced biting attack upon a pneumatic hose. Attacks decreased within and across sessions at low intensities and high frequencies of shock, but increased within and across sessions at higher intensities and lower shock frequencies. Stimuli paired with shock, when presented alone, came to produce biting, and stimuli correlated with shock parameters that produced increases in responding within sessions produced similar increases when presented alone. Further experiments showed that continuing exposure to shock also produced lever pressing or chain pulling, with longer shock exposure again producing higher response rates. Whereas biting generally decreased throughout the intershock interval, manual responding generally increased as shock time approached, but immediately before shock was often suppressed. Following shock, biting attack predominated over manual behavior. The results suggest a possible explanation for the extreme resistance of avoidance behavior to extinction, and may also partially explain the persistence of responding during schedules of response-produced shock. Relationships of the present findings to naturalistic observations of relations between fleeing, freezing, and fighting performances are discussed.

Journal Article↗
PubMed1968

Attack produced by intermittent reinforcement of a concurrent operant response.

Squirrel monkeys pressed a lever to produce food on several fixed-ratio schedules; they could also bite a rubber hose. Biting attack occurred during the postreinforcement pause and in early portions of the ratio response run. Also, biting attacks increased after transitions to higher values of the fixed-ratio requirement and in extinction. The results show that extinction-induced aggression effects occur in primates.

Aggression↗
PubMed1968

Biting attack by rats in response to aversive shock.

Paired rats are known to behave aggressively when given painful electric shocks. The present study developed a procedure whereby individual rats given shocks might bite an inanimate target object. Unavoidable shock was delivered to the rat while it was restrained in a position close to, and facing a target object. Biting of the target was recorded automatically. Shock caused the rat to bite metal, wood, or rubber targets. Biting was most frequent immediately after shock and decreased as a direct function of time since the shock. Almost every shock produced biting and the behavior continued as long as the shocks were delivered. Biting ceased within and between sessions when shocks were discontinued. These results show how the pain-aggression relation can be studied objectively with rats.

Aggression↗
PubMed1968

Effects of shock intensity and duration on the frequency of biting attack by squirrel monkeys.

Squirrel monkeys were periodically exposed to brief tail-shocks in the presence of a rubber tube connected to a pneumatic switch. Biting attack upon this tube was found to be a decreasing function of time since shock delivery and a direct function of shock intensity and duration. These results parallel findings in investigations employing more "naturalistic" social situations, indicating that attack against the inanimate and animate environment is a direct function of the intensity of an aversive stimulus. The results also demonstrate that frequency of biting attack as a datum is sensitive to several experimental manipulations.

Aggression↗