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Biomedical subjects

N M Blampied

Publications and source records attributed to N M Blampied.

15 recordsLinked to original sources
PubMed2001

Sensitivity to relative reinforcer rate in concurrent schedules: independence from relative and absolute reinforcer duration.

Twelve pigeons responded on two keys under concurrent variable-interval (VI) schedules. Over several series of conditions, relative and absolute magnitudes of reinforcement were varied. Within each series, relative rate of reinforcement was varied and sensitivity of behavior ratios to reinforcer-rate ratios was assessed. When responding at both alternatives was maintained by equal-sized small reinforcers, sensitivity to variation in reinforcer-rate ratios was the same as when large reinforcers were used. This result was observed when the overall rate of reinforcement was constant over conditions, and also in another series of concurrent schedules in which one schedule was kept constant at VI ached 120 s. Similarly, reinforcer magnitude did not affect the rate at which response allocation approached asymptote within a condition. When reinforcer magnitudes differred between the two responses and reinforcer-rate ratios were varied, sensitivity of behavior allocation was unaffected although response bias favored the schedule that arranged the larger reinforcers. Analysis of absolute response rates ratio sensitivity to reinforcement occurrred on the two keys showed that this invariance of response despite changes in reinforcement interaction that were observed in absolute response rates on the constant VI 120-s schedule. Response rate on the constant VI 120-s schedule was inversely related to reinforcer rate on the varied key and the strength of this relation depended on the relative magnitude of reinforcers arranged on varied key. Independence of sensitivity to reinforcer-rate ratios from relative and absolute reinforcer magnitude is consistent with the relativity and independence assumtions of the matching law.

Animals↗
PubMed1999

A multiple-baseline, double-blind evaluation of the effects of trimeprazine tartrate on infant sleep disturbance.

Infant sleep disturbance involving chronic night waking and resistance to settling to sleep or returning to sleep is a common problem for families with children 6-27 months old. Prescription and nonprescription sedatives are frequently administered without clear evidence that they are effective as either long-term or short-term palliatives. Trimeprazine tartrate, administered either 15 mg/5 mL or 30 mg/5 mL, was compared with both baseline and placebo in a multiple-baseline-across participants, double-blind study. No clinically significant effects of the low dose were detected, whereas the effects of the high dose were not consistently replicated across nor within participants. During active drug treatment, only 2 of 12 children achieved Sleep Behaviour Scale scores indicative of nonproblem sleep. Trimeprazine tartrate is not recommended as a pharmacological treatment for infant sleep disturbance unless as an adjunct to a behavioral therapy program.

Child, Preschool↗
PubMed1995

Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state.

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.

Journal Article↗
PubMed1993

A behavioral model of infant sleep disturbance.

Chronic sleep disturbance, such as bed refusal, sleep-onset delay, and night waking with crying, affects 15% to 35% of preschool children. Biological factors, particularly arousals associated with recurrent episodes of rapid-eye-movement sleep, render infants vulnerable to repeated awakenings. Parental failure to establish appropriate stimulus control of sleep-related behaviors and parent-mediated contingencies of reinforcement for sleep-incompatible behaviors may shape and maintain infant sleep disturbance. Treatment and prevention strategies are discussed, and research needs are identified.

Behavior Therapy↗
PubMed1991

Unenlightened: an unsuccessful attempt to promote the use of cycle lights at night.

The risks of bicycle riding are greatly increased at night, especially if the cyclist does not have lights. Over 13 winter weeks a community behavioural intervention promoting cycle light use was implemented in the city of Christchurch, New Zealand, at two tertiary educational institutions. A third location served as a control. Baseline data from inspection of parked cycles and street observation of cycle riders showed that about 60% of cycles were not fitted with lights and between 40% and 60% of cyclists rode without legal lights, with the percentages varying as functions of sunset time, weather, and time of night. At neither experimental location did prompting, an incentive competition, nor performance feedback increase the number of parked cycles with lights or increase the number of cyclists observed riding with lights.

Accidents, Traffic↗
PubMed1991

Treatment of infant sleep disturbance by trimeprazine in combination with extinction.

Chronic sleep disturbance is a common problem in preschool children. Prescription and non-prescription sedatives provide short-term palliative relief. Behavioral extinction by withdrawal of parental attention is enduringly effective but may be distressing short-term because of postextinction bursts of intense activity by the child. This study evaluated the effects of combining extinction and sedative medication (trimeprazine tartrate), prescribed in a reducing dose over the first 10 days of extinction. Control groups received either extinction alone or a placebo administered double-blind. After baseline, all subjects reduced their sleep disturbance to low levels, the extinction and placebo groups declining slowly, the medication group abruptly. These gains were maintained at follow-up. Measures of infant security and maternal anxiety showed improvements with treatment.

Arousal↗
PubMed1989

Methylscopolamine and conditioned location avoidance.

On alternate days, rats were confined to one side of a shuttlebox following IP administration of saline and to the other following the peripherally-acting muscarinic antagonist, methylscopolamine (1.2 mg/kg). They later avoided the side associated with the drug effect. By duplicating an earlier finding with centrally- and peripherally-acting scopolamine, this result identified aversive peripheral actions of the two drugs as mainly responsible for the effects observed.

Animals↗
PubMed1989

Quantification of the effects of chlorpromazine on performance under delayed matching to sample in pigeons.

The effects of four doses of chlorpromazine (dose range 0.5 to 12.5 mg/kg) on performance under a delayed matching-to-sample procedure in pigeons was investigated, using the exponential model of memory (White, 1985). Performance was measured using a bias-free measure of discriminability, log d (Davison & Tustin, 1978), and negative exponential functions were fitted to individual-subject and group data at each dose level. A decrease in matching accuracy was found to be caused by an increase in the rate of forgetting, b, and a decrease in the initial discriminability, log d0. Changes in rate of forgetting and discriminability occurred at doses that had no statistically significant effect on response latency. The exponential model of memory accounted well for the data and provided a useful way of quantifying the effects of chlorpromazine on the processes involved in delayed matching-to-sample performance.

Animals↗
PubMed1983

Defensive burying: effects of diazepam and oxprenolol measured in extinction.

When a rat is shocked via a prod in a chamber with sawdust on the floor it will typically push the flooring material with snout and forepaws towards and over the prod. We administered diazepam (.5 and 1.0 mg/kg) and oxprenolol (10 and 20 mg/kg) the day following shock exposure, and observed the complete suppression of burying by diazepam, and some suppression with oxprenolol. These effects are independent of interference with initial association of shock and prod, and of changes in general activity.

Animals↗
PubMed1981

Aversive stimulus properties of scopolamine.

The drug state produced in rats by intraperitoneal injections of scopolamine hydrobromide (1.2 mg/kg) was treated as a putative aversive US. This US was paired with a distinctive spatial location in a shuttle box for 6 of 12 daily sessions by confining the subject to one side following scopolamine and to the other side following saline (6 sessions). Two groups of 8 subjects each received zero and 20 min post-injection delays respectively. Following zero delay, but not 20 min delay, subjects avoided the side associated with scopolamine in drug-free, free choice tests. This is evidence that the immediate post-injection drug state induced by scopolamine is aversive.

Animals↗
PubMedDate not supplied

Scopolamine induced changes in activity and reactions to novelty.

The behavior of hooded rats was observed in an exploration box comprising novel and familiar halves following IP injections of 0.1, 0.25, 0.5, 0.75 or 1.00 mg/kg scopolamine or isotonic saline. Drug administration occurred after, rather than before, exposure to one of the alternative halves. All doses decreased reactions to the previously inaccessible novel half but decreases were greater for the 2 lowest doses. Rearing behavior was also suppressed by each dose whereas the number of apparatus cells entered (locomotion) was decreased by low doses but increased by high. The 3 behavioral measures showed declines in frequency during the course of each experimental session. However, low doses of the drug enhanced and high doses retarded these declines for rearing and cells entered. The study illustrated the difficulty in explaining data by unitary processes (such as attenuated habituation) when several behavioral indices and drug doses are employed within a single investigation.

Animals↗
PubMedDate not supplied

Effects of 3-acetylpyridine on spontaneous alternation in the mouse.

When administered to mice, 3-acetylpyridine has been shown to selectively destroy the hippocampa neural fields CA3 and CA4. Adult mice, injected i.p. with150 mg/kg 3-acetylpyridine showed a reduced frequency of spontaneous alteration(48%) in a T-maze, compared with saline injcetd controls (73%). The pattern of latency change in the experimental mice was consistent with a failure to habitatue normally. these behavioral effects of 3-acetylpyrdine resemble those observed following lesions of the hippocampus induced by stereotaxic surgery.

Animals↗