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Biomedical subjects

J E Barrett

Publications and source records attributed to J E Barrett.

At least 127 records · Page 7Linked to original sources
PubMed1982

Effects of chlorpromazine and d-amphetamine on schedule-controlled and schedule-related behavior of rabbits.

A lever-lifting response by Dutch Belted and New Zealand White rabbits was maintained in water-deprived animals by 0.26% saccharin solution and in food-deprived animals by food pellets under a multiple 3-min fixed-interval (FI) 30-response fixed-ratio (FR) schedule. Rabbits responding for the saccharin solution had food freely available during the session and in the home cage, whereas those responding for pellets had water continuously available during the session as well as in the home cage. Under nondrug conditions the FR and FI schedules controlled different rates and patterns of responding in the rabbit that were characteristic of those found with other species. In addition, eating or drinking occurred during the initial portion of the FI under the saccharin solution and initial food presentation schedules, respectively. Doses of d-amphetamine (0.1--10.0 mg/kg) increased responding under the FI and FR schedules of food delivery, but increased only FI responding maintained by the saccharin solution. Doses of 3.0--10.0 mg/kg d-amphetamine produced extremely high (300--800% of control) rates of stereotyped perseverative level responding. Schedule-related eating or drinking were unaffected or decreased at doses of d-amphetamine that increased schedule-controlled responding. Chlorpromazine (0.03--0.3 mg/kg) increased FI responding maintained both by saccharin and food, whereas FR responding generally was unaffected at these dose levels; eating but not drinking was increased with chlorpromazine. Since the behavioral effects of drugs such as amphetamine and chlorpromazine differ somewhat in the rabbit from those found with other typically studied nonhuman mammals, further studies with the rabbit may yield useful information for comparative behavioral pharmacology.

Animals↗
PubMed1982

Antipsychotic drug effects on the behavior of squirrel monkeys differentially controlled by noxious stimuli.

The effects of several antipsychotic compounds were examined on two types of behavioral performances of squirrel monkeys. Both behaviors occurred simultaneously and were maintained separately by different schedules using noxious stimuli. Steady rates of responding were maintained when a chain pulling response postponed electric shock delivery (avoidance schedule). Concurrently, positively accelerated rates of responding were maintained on a lever where the first response after 3 min produced electric shock (fixed-interval 3-min schedule). The effects of the different drugs depended both upon whether the behavior postponed or presented shock and on the particular drug. Chlorpromazine (0.001-0.03 mg/kg), haloperidol (0.001-0.01 mg/kg), molindone (0.001-0.03 mg/kg) and thiothixene (0.001-0.03 mg/kg) increased slightly or had no effect on responding under the shock-postponement schedule at doses that decreased responding maintained by shock presentation. The effects of clozapine, a clinically effective antipsychotic compound, differed markedly from the other antipsychotic drugs. Clozapine (0.01-1.0 mg/kg) increased responding maintained by the presentation of shock at doses that decreased responding under the shock-postponement schedule. Higher doses of these drugs decreased responding under both schedules and, with the exception of clozapine, resulted in increased frequency of shocks under the postponement schedule.

Animals↗
PubMed1981

Effects of chlordiazepoxide and d-amphetamine on responding suppressed by conditioned punishment.

Key pecking by two pigeons, maintained under a variable-interval two-minute schedule of food presentation, was suppressed when each response produced a five-second visual stimulus that was occasionally paired with shock. Stimulus-shock pairings occurred independently of responding according to a variable-time six-minute schedule for one bird or once per session for the other bird. The effects of chlordiazepoxide and d-amphetamine were assessed on this baseline of behavior suppressed by conditioned punishment. Chlordiazepoxide produced dose-related increases in the rate of punished responding, whereas d-amphetamine produced only decreases. In addition, chlordiazepoxide produced dose-related increases in response rate during the response-produced and response-independent stimulus presentations; d-amphetamine, however, only decreased responding during stimulus presentations.

Journal Article↗
PubMed1981

Inservice training for part-time dental faculty.

Part-time faculty outnumber full-time faculty in clinical dentistry departments. They spend many hours in contact with students and often serve as role models of dental practitioners. Yet, part-time faculty have had very little formal training in instructional techniques. This article describes an inservice training program for part-time faculty involving workshops, weekly meetings, and practice sessions. The program was developed to provide training in some basic teaching techniques. Part-time faculty were given an instructional manual and copies of student syllabi and the opportunity to participate in the development and use of the student criteria sheets. The results of the program indicate that the faculty felt the program was an effective use of their time and they will accept, and even look forward to, future inservice training opportunities.

Educational Measurement↗
PubMed1981

Effects of methaqualone on punished and nonpunished behavior.

Effects of methaqualone were studied on the key pecking of pigeons maintained under various schedules of food presentation. One group of pigeons responded under a multiple fixed-ratio, fixed-interval schedule. Methaqualone (3.0--10.0 mg/kg) decreased the relatively low rates of responding under the fixed-interval schedule but left unchanged the higher rates under the fixed-ratio schedule. Higher doses of methaqualone decreased responding under both schedules. Another group of pigeons responded under a fixed-interval schedule in which responding was suppressed (punished) by electric shock presented according to a fixed-ratio schedule. Suitable doses of methaqualone increased punished responding. A 2-fold change in shock intensity produced little change in rates and patterns of responding, yet methaqualone produced much greater increases in responding punished by the lower intensity shock. Regardless of whether or not responding was punished, the effects of methaqualone on fixed-interval performance depended on the rate of responding in the absence of drug; low rates of responding in the early periods of the fixed-interval were increased by doses that increased less or decreased the higher response rates in the later periods. These rate-dependent effects of methaqualone were modulated by the shock intensity; the rate-increasing effects obtained at the lower intensity shock were uniformly greater than those obtained at the higher intensity. The behavioral effects of methaqualone were generally qualitatively similar to effects reported for many sedative hypnotics.

Animals↗
PubMed1981

Effects of d-amphetamine on responding of squirrel monkeys maintained under second-order schedules of food presentation, electric shock presentation or stimulus-shock termination.

The effects of d-amphetamine (0.01-5.6 mg/kg i.m.) were studied on lever pressing of squirrel monkeys maintained under various second-order schedules by a visual stimulus (S) that, with separate monkeys, was occasionally paired with the presentation of either food, electric shock or with the termination of a stimulus in the presence of which shocks occurred. Under one condition, the first response after 5 min produced a 3-sec stimulus change and the fourth stimulus change was followed immediately by food delivery, electric shock presentation or by the termination of a stimulus in the presence of which shocks occurred [fixed-ratio (FR); fixed-interval (FI) [FR 4 (FI 5-min:S)]. The effects of d-amphetamine were also studied under the food- and shock-presentation schedules when food or shock occurred only once, at the end of each session, after completion of 53n 3-min fixed-intervals all of which ended with a brief stimulus change [FR 10 (FI 3-min : S)]. Under a third condition, each thirtieth response produced the 3-sec brief stimulus (FR 30 : S) and the first FR 30 completed after 5 min elapsed produced the stimulus followed by food or, with separate monkeys, electric shock [FI 5-min (FR 30:S)]. Low to intermediate doses of d-amphetamine (0.03-0.3 mg/kg) generally increased and higher doses (0.56-5.6 mg/kg) decreased responding under all conditions. The effects of d-amphetamine on responding maintained by brief stimuli under different types of second-order schedules are generally similar, regardless of the type of reinforcing event or particular second-order schedule.

Animals↗
PubMed1980

A comparison of the effects of d-amphetamine, cocaine, imipramine and pentobarbital on local and overall rates of responding maintained under a four-component multiple fixed-interval schedule.

Key pecking of pigeons was maintained under a four-component multiple fixed-interval schedule with values of 1-min, 3-min, 5-min and 10-min. Each schedule value was correlated with a different key color, each of which controlled distinctively different performances. This schedule generated a range of response rates both within and across the different interval components that permitted a direct comparison of drug effects on local and overall rates of responding. d-Amphetamine, cocaine, imipramine and pentobarbital all increased low local response rates at doses that did not affect or decreased higher rates within each fixed interval. Similar effects were obtained when different overall rates of responding were analyzed except that imipramine and pentobarbital also increased the highest overall rates occurring under the 1-min schedule.

Animals↗
PubMed1980

Maintenance of responding by squirrel monkeys under a concurrent shock-postponement, fixed-interval shock-presentation schedule.

A chain-pulling response was initially developed under a shock-postponement (avoidance) schedule with two squirrel monkeys. Few responses occurred on a lever where responding initially had no scheduled consequence or, subsequently, when a 3-minute fixed-interval shock-presentation schedule was concurrently arranged for lever responses. Appropriate rates and patterns of lever responding developed and were later maintained under the fixed-interval 3-minute shock-presentation schedule alone when the chain and shock-postponement schedule were removed. When both the shock-postponement and shock-presentation schedules were again simultaneously in effect, steady rates of chain pulling were maintained by the shock-postponement schedule and positively accelerated rates and patterns were maintained on the lever by the shock-presentation schedule. Response rates under both schedules were directly related to shock intensity. A history of exposure to a shock-postponement schedule, even though with a topographically different response and manipulandum, was sufficient for the development and eventual maintenance of responding by the presentation of shock. Further, differential performances can be maintained simultaneously by the presentation and postponement of electric shock.

Animals↗
PubMed1980

Effects of ethanol on multiple fixed-interval fixed-ratio schedule performances: dynamic interactions at different fixed-ratio values.

Key pecking by three pigeons was maintained under a multiple fixed-interval fixed-ratio schedule of food presentation. The fixed-interval value remained at 3 minutes, while the fixed-ratio size was increased systematically in 30-response increments from 30 to either 120 (two pigeons) or 150 (one pigeon). At least two lower fixed-ratio values were also redetermined. The effects of ethanol (5 to 2.5 g/kg) were assessed at each of the different schedule parameters. Both overall and running response rates under the fixed-ratio schedule decreased with increases in the size of the fixed-ratio schedule; pause duration under the fixed-ratio schedule was directly related to increases in fixed-ratio size. Overall and running rates of responding under the fixed-interval schedule changed little with increases in the size of the fixed-ratio schedule. Despite the relative invariance of fixed-interval responding across the different fixed-ratio values, the effects of ethanol on responding under the fixed-interval schedule differed depending on the size of the fixed-ratio schedule. Greater increases occurred in both overall and in lower local rates of responding under the fixed-interval schedule when the fixed-ratio value was 120 or 150. The effects of ethanol on responding under the fixed-ratio schedule also depended on the size of the fixed ratio. Increases in responding under the fixed-ratio schedule were typically greater at the higher fixed-ratio values where response rates were lower. When the effects of ethanol were redetermined at the lower fixed-ratio parameter values, rates and patterns of responding were comparable to those obtained initially. However, the dose-effect curves for responding under both fixed-ratio and fixed-interval schedules were shifted up and to the right of those determined during the ascending series. The effects of ethanol can depend on rate or responding, behavioral history, and the context in which behavior occurs.

Animals↗
PubMed1980

Dental faculty training in clinical instruction.

Most dental faculty have had no formal training in education prior to their clinic instructor role and many report a need for training in educational methods and tutorial skills. Organized methods for establishing student performance criteria and improving instructional skills presented in a well-designed inservice training program utilizing prepared training materials, workshop learning, and practice sessions can increase teacher effectiveness in clinic instruction.

Education, Continuing↗
PubMed1979

Effects of chlordiazepoxide on comparable rates of punished and unpunished responding.

Identical overall rates and patterns of key pecking by pigeons were maintained under a multiple fixed-interval schedule of food presentation. In one component, every thirtieth response produced an electric shock (punishment) whereas during the other component the response that produced food had to be preceded by a pause of a minimum (10 or 11 s) duration. Although chlordiazepoxide (1.0--17.0 mg/kg) increased both punished and unpunished responding, greater increases were uniformly obtained with punished responding.

Animals↗