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Biomedical subjects

A V Bacotti

Publications and source records attributed to A V Bacotti.

7 recordsLinked to original sources
PubMed1981

Clozapine effects on responding maintained under shock presentation and shock termination schedules.

Clozapine, a novel antipsychotic, was studied in different squirrel monkeys responding under a 3-min fixed-interval schedule of stimulus-shock termination and a multiple 5-min fixed-interval schedule of shock presentation, 5-min fixed-interval schedule of stimulus-shock termination. Some doses (0.1-1.0 mg/kg IM) of clozapine increased responding under each fixed-interval schedule, whereas higher doses (3.0 and 5.6 mg/kg IM) usually decreased responding under each schedule. Lower response rates maintained under the stimulus-shock termination schedule were increased relatively more by clozapine than were higher rates of responding maintained under the fixed-interval schedule of shock-presentation. The present results illustrate that the effects of clozapine on schedule-controlled behaviors of squirrel monkeys differ from those of other antipsychotics.

Animals↗
PubMed1979

Pentobarbital and d-amphetamine effects on concurrent performances.

The effects of pentobarbital and d-amphetamine were studied in pigeons responding under several concurrent fixed-ratio variable-interval and concurrent fixed-ratio fixed-interval schedules of food presentation. Drug effects were compared with different fixed ratios, fixed and variable intervals, changeover delays, and with the schedules operating singly. Doses of d-amphetamine that increased or did not affect responding under the interval schedules decreased responding under the fixed-ratio schedule, whereas doses of pentobarbital that increased responding under the fixed-ratio schedule decreased or eliminated responding under the interval schedules. These effects depended both on the schedule of food delivery and the parameters of schedules arranged concurrently. Pentobarbital increased responding under the fixed-ratio schedule with 4-minute and 10-minute interval schedules arranged concurrently, but not with 1.5-minute schedules. d-Amphetamine decreased concurrent ratio and interval responding with the 1.5-minute interval schedules, but either increased or did not affect responding with the longer intervals. Changes in the parameter of one schedule altered responding controlled by that schedule and also other concurrent performances. As a consequence, the effects of drugs on each behavior were altered.

Animals↗
PubMed1978

Responding under schedules combining response-dependent and response-independent shock delivery.

Lever pressing of three squirrel monkeys with experience under continuous avoidance schedules was maintained by response-produced shock under a 5-minute variable-interval schedule. Responding decreased when half of the scheduled shocks were delivered independently of lever pressing and decreased further when all shocks were independent of lever pressing. Responding was lowest when all shocks were eliminated. When the proportion of response-dependent shocks increased, responding increased. This relation occurred even though the frequency and temporal distribution of shock delivery remained the same. Responding of two monkeys increased in a graded fashion as the frequency of shock was increased by arranging variable-time 5-minute, 2-minute, and 1-minute schedules jointly with the variable-interval 5-minute schedule. Thus, increasing the proportion of response-independent shocks decreased responding when the overall frequency of shocks stayed the same, but increased responding when the overall frequency of shock delivery increased.

Journal Article↗
PubMed1977

Matching under concurrent fixed-ratio variable-interval schedules of food presentation.

Four pigeons were exposed to concurrent fixed-ratio, variable-interval schedules of food presentation. The fixed-ratio requirement was either 25, 50, 75, or 100 responses, with the variable-interval schedule parameter held constant at 4 minutes. A delay time was imposed between a changeover from one schedule to the other and subsequent food availability. The delay time was varied at each ratio requirement over four values; no delay, 0-second delay, 1.5-second delay, and 5.0-second delay. As the fixed-ratio requirement or the delay time increased, a greater proportion of the total responses and time spent responding occurred under the variable-interval schedule relative to the proportion of food deliveries under that schedule. Neither relative overall response rate nor relative time spent responding equalled the relative frequency of food presentation, as would be predicted by a linear "matching" model. Rather, these data were described by power functions with slopes of approximately 1.0 and intercepts greater than 1.0. In the terms of Baum's (1974) analysis, these deviations from linear matching represent bias in favor of responding under the interval schedule. Bias, as reflected in the intercept of the power function, was greater for the ratio of time than the ratio of responses.

Journal Article↗
PubMed1976

Effect of chlordiazepoxide on schedule-controlled responding and schedule-induced drinking.

Lever pressing of four rats was maintained under a multiple fixed ratio 80, fixed interval 2-min schedule of food presentation. Water was concurrently available from a drinking tube. Overall rates of lever pressing were highest under the fixed ratio schedule and, for three rats, most drinking occurred during the pause preceding responding under the fixed interval schedule. Chlordiazepoxide increased the lower rates of lever pressing maintained under the fixed interval schedule but generally decreased the higher response rates under the fixed ratio schedule. The effects of chlordiazepoxide on schedule-induced licking also depended on the extent to which this response occurred in each schedule component. Typically chlordiazepoxide produced relatively greater increases in the lower levels of licking and either increased less or decreased licking in that component where, under control conditions, this response was more extensive. Chlordiazepoxide also produced overall increases in the total amount of water consumed during the session. When the number of food pellets obtained during the experimental session was given all at one time in the home cage, the amount of water ingested over a period of time equivalent to the session duration was substantially less than that consumed during the experimental session. Chlordiazepoxide did not increase home cage water consumption under this condition.

Animals↗