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Biomedical subjects

T N Tombaugh

Publications and source records attributed to T N Tombaugh.

29 records · Page 2Linked to original sources
PubMed1981

Ethanol-Metrecal diets: I. effects of different levels of ethanol-derived kilocalories on consumption of diet, body weight and grams of ethanol ingested.

Three experiments investigated the relationship between ethanol consumption and the percentage of ethanol-derived kilocalories contained in liquid diets. Rats were chronically maintained on diets where different concentrations of ethanol (10%, 12%, 14%) were added to Metrecal so that 41%, 49% and 57% of all kilocalories consumed were derived from ethanol. The ethanol-Metrecal diet served as the sole source of calories. Results demonstrated that rats can be maintained for extended time periods on diets where ethanol contributed approximately 50% of the daily kilocalories. Inspection of consummatory profiles revealed that an initial decrease occurred in volume of diet consumed when levels of ethanol were increased. This was followed by a gradual increase in the level of consumption until a new asymptotic level was established. Grams of ethanol/kg of body weight remained relatively constant over the range of ethanol concentrations employed. The results were discussed in respect to three factors controlling consummatory behavior--sensory stimuli, caloric intake and quantity of ethanol ingested.

Acoustic Stimulation↗
PubMed1981

Ethanol-Metrecal diets: II. Failure to obtain impaired performance on a series of appetitively and aversively motivated tasks.

Rats were chronically maintained on ethanol-Metrecal diets where either 37%, 41%, 49% or 57% of the total kilocalories were derived from ethanol. In three experiments animals were tested on a series of problems (passive avoidance, shuttle avoidance, simultaneous and successive discrimination, and complex spatial maze learning) 6 to 8 weeks after the diet had been withdrawn. There was no evidence that chronic ethanol regimes impaired either learning or memory processes.

Alcohol Drinking↗
PubMed1981

Application of contingent physical restraint to suppress stereotyped body rocking of profoundly mentally retarded persons.

The effectiveness of contingent restraint in reducing stereotyped body rocking of profoundly retarded subjects was investigated to determine (a) whether restraint reduced stereotyped body rocking and (b) the degree to which the effectiveness of restraint depended upon where in the behavioral sequence it was administered. Results showed that restraint, in comparison to no restraint, reduced the amount of body rocking. Also, restraint was judged to be generally more effective if it were applied when the subject was bent over in the middle of the response sequence rather than administered while the subject was sitting upright at the end of the response sequence. The results were interpreted in terms of response chaining and postural feedback. Implications for the utilization of physical restraint as a behavioral intervention were discussed.

Adolescent↗
PubMed1980

Extinction and dopamine receptor blockade after intermittent reinforcement training: failure to observe functional equivalence.

Response decrements in an operant task produced by either extinction or by the dopamine receptor blocker pimozide were examined in three experiments which employed intermittent reinforcement schedules. In contrast to the congruency between these treatments previously observed following continuous reinforcement training, treatment with pimozide was markedly more effective than extinction in decreasing performance after training with variable interval, fixed interval, and fixed ratio reinforcement. The two treatments also produced substantially different patterns of responding. A shift from extinction to pimozide did not alter the progressive decline in response rate over days, but a shift from pimozide to extinction caused a pronounced increase of performance. These results indicate that the pimozide and extinction treatment did not produce functionally equivalent effects, and that the role of dopamine on reward processes should not be inferred from comparisons between pimozide and extinction.

Animals↗
PubMed1980

Effects of pimozide on accuracy of performance and distribution of correct responding on a simultaneous discrimination task in the rat.

After training rats in a simultaneous discrimination problem, pimozide, a dopamine receptor blocker, was administered to determine whether accuracy of performance would be disrupted. Each animal received five doses of pimozide (vehicle, 0.05, 0.10, 0.30, and 0.60 mg/kg) delivered in a Latin Square sequence with five non-drug days between injections. Pimozide did not disrupt well established discrimination behavior at any of the doses even though a decrease in rate of responding was observed at the two higher doses. These results provide additional evidence that DA neutrons are not essential in the mediation of previously learned associations.

Animals↗
PubMed1979

Effects of dopamine receptor blockade on alimentary behaviors: home cage food consumption, magazine training, operant acquisition, and performance.

Administration of the dopamine receptor blocker pimozide (1.0 mg/kg) disrupted the initiation, but not the maintenance, of home cage food consumption. Likewise, the number of pellets consumed during magazine training was decreased among pimozide-treated rats during the first, but not the second day of training. The acquisition of a bar-press response for food reinforcement (using a retractable bar) was severely retarded by pimozide. However, such an impairment was not evident if animals initially received 2 training days in the absence of the drug. Further, among rats trained to bar press to asymptote using a nonretractable bar, pimozide reduced the within and between days bar-press rate such that performance was indistinguishable from that of animals placed on extinction in the absence of the drug treatment. When transferred from the pimozide treatment to extinction in the absence of drug, the response rate increased to the level observed during the first session of either extinction or pimozide in the continuous reinforcement condition. The results are discussed in terms of sensory-motor and reinforcement consequences of dopamine receptor blockade.

Animals↗