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Biomedical subjects

J E Barrett

Publications and source records attributed to J E Barrett.

At least 163 records · Page 9Linked to original sources
PubMed1976

Effects of alcohol, chlordiazepoxide, cocaine and pentobarbital on responding maintained under fixed-interval schedules of food or shock presentation.

Responding by three squirrel monkeys was maintained under multiple-and single-component 5-minute fixed-interval (FI) schedules of either food or electric shock presentation. Under the multiple schedule, a response after 5 minutes had elapsed produced either food or shock depending on the prevailing stimulus conditions; single-component FI schedules maintained responding either by food or shock presentation alone. Responding under either the food or the shock schedules was positively accelerated throughout each FI. During certain phases of the experiment, overall response rates maintained by foor were comparable to those maintained by shock. Alcohol (1.0-3.0 g/kg), chlordiazepoxide (1.0-10.0 mg/kg) and pentobarbital (1.0-10.0 mg/kg) increased responding maintained by food but decreased responding maintained by shock. These effects were obtained under both the multiple- and single-component schedules. Low to intermediate doses of cocaine (0.1-1.0 mg/kg) increased responding maintained by either food or shock, whereas higher doses (3.0 mg/kg) generally decreased responding under these conditions. The effects of chlordiazepoxide were also studied with one monkey when response rates maintained by food or shock were equal, when rates of food-maintained responding were lower than those maintained by shock and, finally, when rates of responding maintained by food were higher than those maintained by shock. Under all of these conditions, chlordiazepoxide increased food-maintained response rates and decreased responding maintained by shock presentation.

Animals↗
PubMed1975

Punished behavior: increases in responding after d-amphetamine.

Responding maintained in squirrel monkeys under a 10-min fixed-interval schedule of food presentation was suppressed by presenting a shock after every 30th response (punishment). During alternate 10-min periods of the same experimental session, but in the presence of a different discriminative stimulus, responding either had no effect (extinction) or postponed delivery of an electric shock (avoidance). During sessions when the avoidance schedule was not in effect, d-amphetamine sulfate decreased punished responding. When the avoidance schedule was present during alternate 10-min periods, however, d-amphetamine (0.01 minus 0.56 mg/kg, i.m.) markedly increased responding during punishment components. Increases in responding during avoidance components were also evident. The effects of d-amphetamine on punished responding depend on the context in which that responding occurs.

Animals↗
PubMed1975

Effects of chlordiazepoxide on schedule-induced water and alcohol consumption in the squirrel monkey.

Lever pressing of five squirrel monkeys was maintained by a 3-min fixed-interval schedule of food presentation. 3 monkeys had water concurrently available and, for a second pair of monkeys, initially water, then increasing concentrations of alcohol (1--3% v/v) were present. Substantial amounts of post-pellet drinking occurred with all five monkeys. The amount of water ingested was approximately 100 ml per session, that of 3% alcohol nearly 63 ml. For the monkeys drinking alcohol, increasing concentrations of alcohol decreased both the rate of lever pressing and the volume of fluid consumed. Chlordiazepoxide (1.0--17.0 mg/kg) produced increases in lever pressing and in the schedule-induced consumption of both 3% alcohol and water.

Alcohol Drinking↗
PubMed1975

Sjöbring personality dimensions: norms for some American populations.

An American version of the MNT Inventory (Sjöbring personality dimensions) was administered to three separate groups of American subjects. Normative data on the Sjöbring dimensions, including correlational data between the dimensions, was reported for these groups and compared to published normative data from prior studies in Sweden and in the United Kingdom. For the American groups, the correlations between dimensions were negligible or very small, in accord with Sjöbring theory. There were similar patterns to the scale scores and to the correlational data for the American groups and comparable Swedish groups. The results suggest that the American version of the MNT inventory is a valid tool for obtaining Sjöbring dimension scores on American subjects.

Adolescent↗
PubMed1975

Conjunctive schedules of reinforcement II: response requirements and stimulus effects.

Responding of three pigeons was maintained under conjunctive fixed-ratio, fixed-interval schedules where a key peck produced food after both schedule requirements were completed. The individual schedule requirements were then successively removed and reinstated with responding maintained under the following conditions: conjunctive fixed-ratio, fixed-time; fixed-time; and fixed-interval schedules. Patterns of responding changed in accord with the successive removal of the schedule requirements. Compared to the conjunctive fixed-ratio, fixed-interval schedule, pause duration increased and response rate decreased under conjunctive fixed-ratio, fixed-time schedules and under fixed-time schedules alone. Overall mean rates of responding were highest and pause duration lowest under fixed-interval schedules. When changes in the keylight colors were correlated with completion of the fixed-ratio, the end of the fixed-interval, or both of these conditions, the pattern of responding was modified and indicated a greater degree of control by the individual schedules. Although two birds showed large increases in interreinforcement time when they were initially exposed to the conjunctive schedule, when responding stabilized this measure was largely invariant for all birds across most schedule conditions.

Journal Article↗
PubMed1974

Conjunctive schedules of reinforcement. I. Rate-dependent effects of pentobarbital and d-amphetamine.

Key pecking of pigeons was maintained under conjunctive schedules of food presentation in which both a fixed-interval and a fixed-ratio schedule had to be completed before a peck produced food. For two pigeons, pecks on a single key completed both schedule requirements (fixed-interval 3-min, fixed-ratio 50 for one bird, fixed-interval 5-min, fixed-ratio 50 for the second). For two other pigeons, each requirement was scheduled on a separate key. On the two-key schedule, a peck after 5 min on the key scheduling the fixed-interval requirement produced food if at least 10 pecks had occurred on the ratio key (conjunctive fixed-interval 5-min, fixed-ratio 10). When each requirement was scheduled on a separate key, response rates on the fixed-ratio key were generally higher in the early portion of the interval and declined as the interval progressed; responding on the fixed-interval key, once initiated, typically remained at a constant rate throughout the interval. Responding under the single-key schedule was characterized by a high rate early in the interval; this then changed to a lower rate that continued until a peck produced food. For all pigeons, increases in response rates with pentobarbital and d-amphetamine were inversely related to the control rate of responding. When equivalent rates on each key of the two-key schedule were compared, both drugs increased rates on the fixed-ratio key less. Although the effects of both drugs were rate dependent, each drug differentially modified the pattern of responding under the single-key schedule.

Animals↗
PubMed1972

Schedules of electric shock presentation in the behavioral control of imprinted ducklings.

The behavioral effects of various schedules of electric shock presentation were investigated during and after the imprinting of Peking ducklings to moving stimuli. The behavior of following a moving imprinted stimulus was differentially controlled by a multiple schedule of punishment and avoidance that respectively suppressed and maintained following behavior. Pole-pecking, reinforced by presentations of the imprinted stimulus, was suppressed by response-produced shock (punishment); various schedules of response-independent shock and delayed punishment had an overall minimal effect. The delivery of response-independent shock in the presence of one of two stimuli, both during and after imprinting, resulted in a marked reduction in choice of the stimulus paired with shock. The experiments provide no support for a differentiation of imprinting from learning on the basis of the behavioral effects of aversive stimuli. Instead, as is the case with other organisms, the schedule under which shock is delivered to imprinted ducklings appears to be an important determinant of the temporal patterning of subsequent behavior.

Animals↗
PubMedDate not supplied

The relationship of presenting physical complaints to depressive symptoms in primary care patients.

OBJECTIVE: To assess the relationship of specific patient chief physical complaints to underlying depressive symptoms in primary care practice. DESIGN: A cross-sectional study that was part of a larger prevalence study of depression in primary care. SETTING: A general medical primary care practice in a teaching medical center in rural New England. PATIENTS: 1,042 consecutive outpatients screened for depression with the Hopkins Symptom Checklist 49-item depression scale and for whom physicians filled out a form recording both specific chief complaints and two aspects of complaint presentation style, clarity and amplification. INTERVENTIONS: None. RESULTS: Complaints that discriminated between depressed and non-depressed patients (at the p = 0.05 level) were sleep disturbance (PPV 61%), fatigue (PPV 60%), multiple (3+) complaints (PPV 56%), nonspecific musculoskeletal complaints (PPV 43%), back pain (PPV 39%), shortness of breath (PPV 39%), amplified complaints (PPV 39%), and vaguely stated complaints (PPV 37%). CONCLUSIONS: Depressed patients are common in primary care practice and important to recognize. Certain specific complaints and complaint presentation styles are associated with underlying depressive symptoms.

Adolescent↗