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V G Laties

Publications and source records attributed to V G Laties.

At least 19 recordsLinked to original sources
PubMed1998

60 Hz electric fields and incandescent light as aversive stimuli controlling the behavior of rats responding under concurrent schedules of reinforcement.

Several reports have shown that animals will sometimes engage in behaviors that reduce their exposure to a 60 Hz electric field (E-field). The field, therefore, can function as an aversive stimulus. In other studies, the E-field at equivalent strengths failed to function as an aversive stimulus. The present experiment, using rats, demonstrates how factors other than field strength can influence whether a subject engages in behavior that reduces field exposure. The general design consisted of giving the rat a choice between two alternatives, one of which sometimes included an added stimulus. Each subject was trained to press each of two levers to obtain food. Pressing one lever was reinforced intermittently under a variable interval 2 min schedule (VI 2); pressing the other lever was reinforced by a second VI 2 schedule operating independently of the first. Under this concurrent schedule the rat spent 50% of the daily 50 min session responding to each of the levers, indicating that they were equally "valued." Next, while the schedules remained in effect, the first response to one of the levers turned on a 100 kV/m E-field which remained on until the rat pressed the other lever. The time spent responding under the schedule associated with the field was reduced by about 5-10%. When the procedure was changed so that no lever presses produced food, i.e., extinction, but the added stimulus contingency remained, the rats spent even less time in the presence of the field. Similar outcomes were observed during both the concurrent food or extinction schedules when incandescent light was used. Thus, both an E-field and incandescent light functioned as aversive stimuli, but the magnitude of the aversiveness was small. Aversiveness depended not only on stimulus intensity, but also on behavioral factors.

Animals↗
PubMed1996

Exposure to combined static and 60 Hz magnetic fields: failure to replicate a reported behavioral effect.

Two experiments failed to confirm the Thomas, Schrot, and Liboff report that low-intensity magnetic fields disrupted the operant behavior of rats. In their experiment, food-deprived rats were trained to press a lever to obtain food pellets under a multiple fixed-ratio (FR) 30, differential reinforcement of low rate 18-24 s (DRL 18-24) schedule. After baseline training, the rats were exposed to a 30 min treatment in a different chamber prior to behavioral testing. When the treatment consisted of a horizontal 60 Hz magnetic field at 5 x 10(-5) Telsa aligned along the north-south axis combined with a static field that reduced the background to 2.61 x 10(-5) Telsa, the rate of lever pressing in the DRL component of the multiple schedule increased reliably during the immediately following test session. Changes in responding were not observed when the rats were exposed to either the static field or the 60 Hz field independently nor during sham exposures to the fields. In the present experiments, only the combined fields, i.e., those reported to be effective, were studied in rats using the same general behavioral and exposure protocol used by Thomas et al [1986a]. In experiment 1, the 2.61 x 10(-5) Telsa was achieved by reducing the vertical component of the static field. In experiment 2, both the horizontal and the vertical components were altered to match those used by Thomas et al. In both experiments additional magnetic field conditions were also studied to ensure that threshold values were exceeded and, in experiment 2, to address concerns about the role of harmonic frequencies of the 60 Hz field. The baseline performances approximated those of Thomas et al. Performances were compared between exposure, sham-exposure and control sessions. None of the exposure conditions altered any of the behavioral measures. The reasons for failing to replicate the results of Thomas et al. remain unknown.

Animals↗
PubMed1996

JEAB and JABA on the World Wide Web: a report to readers.

The Journal of the Experimental Analysis of Behavior (JEAB) and the Journal of Applied Behavior Analysis (JABA) have both established home pages on the World Wide Web. Their addresses are: http://www.envmed.rochester.edu/wwwrap/beh avior/jeab/jeabhome.htm http://www.envmed.rochester.edu/wwwrap/beh avior/jaba/jabahome.htm An important feature of these pages is a powerful program that permits rapid full-text searches of a database consisting of the nearly 5,000 abstracts that have accompanied articles published in JEAB since 1958 and in JABA since 1968. An electronic version of a single article from each issue of each journal is now made available soon after the paper edition of the journal appears.

Computer Communication Networks↗
PubMed1993

Taking stock: The first 25 years of the Journal of Applied Behavior Analysis.

Some aspects of the performance of the Journal of Applied Behavior Analysis (JABA) are described on the occasion of the journal's 25th anniversary. Comparative circulation data are presented. JABA's influence on the scientific community is measured by examining the citation history of articles that it has published, with attention to both frequency and source of the citations. The influence that other journals have on JABA's authors is assessed through an analysis of citations made by those authors in this journal's reference lists. The citation history indicates clearly that JABA has made substantial contributions toward producing methods useful in coping with a wide variety of problem behaviors, from profound developmental disabilities (such as autism) to the simpler behavioral problems that interfere with normal functioning in home and at school. Recently, the journal has devoted many issues and parts of issues to special topics, in a concerted effort to reflect the increasing breadth of applied behavioranalysis.

Journal Article↗
PubMed1989

Comparison of 60-Hz electric fields and incandescent light as aversive stimuli controlling the behavior of rats.

Rats were exposed to two procedures which enabled them to press a lever to turn off a 90 or 100 kV/m 60-Hz electric field or, later in the study, illumination from an incandescent lamp. Under one procedure, a response turned off the stimulus for a fixed duration, after which the stimulus was turned on again. A response during the off-period restarted the fixed duration. None of the rats turned the field off reliably. Next, under an alternative procedure, pressing one lever turned the field off; pressing the other lever turned it back on; responding under those conditions differed little from that seen at 0 kV/m. Under both procedures, when illumination from an incandescent lamp served as the stimulus, each rat did turn the stimulus off, and performances varied with stimulus intensity. The results show that a 100 kV/m 60-Hz electric field is not sufficient to function as an aversive stimulus under two procedures where illumination from a lamp does function as an aversive stimulus.

Animals↗
PubMed1989

Evidence of tolerance following repeated exposure to toluene in the rat.

Toluene shares pharmacological properties with other abused central nervous system depressants such as ethanol and the barbiturates. Although tolerance has been clearly demonstrated for these classic CNS depressants, evidence of tolerance following repeated toluene exposure is equivocal. The present work examined if tolerance would develop to the effects of repeated toluene exposure on learned behavior and examined the possibility that external discriminative stimuli could influence these effects. Two variants of a fixed-consecutive-number schedule of reinforcement were used as components in a multiple schedule. The components differed in whether or not behavior within them was under the control of external discriminative stimuli. Rats were exposed daily for two hours to toluene (1780 to 4500 ppm). Different patterns of effects emerged from repeated exposure; some rats displayed tolerance while the performance of others deteriorated. Behavior controlled by external discriminative stimuli was more resistant to disruption and showed tolerance more readily than did behavior not under such control.

Animals↗
PubMed1987

Control of animal pain and distress in behavioral studies that use food deprivation or aversive stimulation.

Imposing moderate amounts of food deprivation on an animal allows the use of reward techniques in studying behavior and poses fewer ethical problems than does the use of aversive procedures. Possible discomfort caused by experiments using aversive stimulation frequently can be reduced. Habituating animals to experimental procedures is almost always a good idea. When the reaction to aversive stimuli is the object of study, animals can be given direct control of the stimulus and the intensity of stimulus they choose can then be measured.

Animal Welfare↗
PubMed1987

Introduction.

Explore the source record for details and available documents.

Journal Article↗
PubMed1987

Double duty.

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Journal Article↗
PubMed1987

Stimulus control and the development of behavioral tolerance to daily injections of d-amphetamine in the rat.

We examined whether daily d-amphetamine administration affected behavior under the control of external stimuli differently than behavior not under such control. Two variants of a fixed-consecutive-number reinforcement schedule were combined in a multiple schedule. An external discriminative stimulus indicated when the schedule requirement for reinforcement had been satisfied in one component, no such stimulus was used in the other component. Reinforcement frequency was roughly equated between the components by reducing the probability of reinforcement in the added stimulus component. Two groups of animals were given daily i.p. injections with equivalent doses of drug. Tolerance to the drug's behavioral effects developed when injections occurred before behavioral evaluation but did so only to a limited extent when injections were given only after the sessions. This indicated that behaving in the presence of the drug facilitated the development of such tolerance. It developed under both stimulus control conditions at both doses; at 3.0 mg/kg, it developed predominantly in those aspects of behavior that were under the control of external discriminative stimuli. Although drug-related decreases in reinforcement frequency in some animals were correlated with behavioral tolerance development, differential tolerance development was not associated consistently with such reductions. Establishing discriminative control of behavior by external stimuli can both reduce sensitivity to repeated d-amphetamine administration and facilitate the development of tolerance to its behavioral effects.

Animals↗
PubMed1985

60-Hz electric fields: detection by female rats.

Female rats were trained to detect a vertical, 60-Hz electric field using the same apparatus and procedure we used previously to study behavioral detection of the field by male rats. Each rat was trained individually to press a lever in the presence of the field and not to press in its absence. Correct detections occasionally produced a food pellet. The probability of detecting the field increased as field strength increased. The threshold of detection--ie, the field strength required for detections at a probability of 0.5 after correction for errors--varied among rats between 3 and 10 kV/m. Behavioral detection by female rats was indistinguishable from that by male rats.

Animals↗
PubMed1985

The roles of stimulus control and reinforcement frequency in modulating the behavioral effects of d-amphetamine in the rat.

The behavioral effects of d-amphetamine have been shown to be modulated by stimulus control, with less impairment of performance occurring when control is great. When the fixed-consecutive-number schedule is used (on which at least a specified consecutive number of responses must be made on one operandum before a single response on another will produce a reinforcer), response rate tends to be invariant but reinforcement frequency is not. This study asks whether the differences in reinforcement frequency that usually accompany changes in stimulus control could themselves be responsible for the performance differences. Two versions of the fixed-consecutive-number schedule of reinforcement were combined into a multiple schedule within which stimulus control was varied but differences in reinforcement frequency were minimized by omitting some reinforcer deliveries during the component that usually had the higher reinforcement frequency. In one component, a compound discriminative stimulus was added with the eighth consecutive response on the first lever; a single response on the second lever was then reinforced. In the other component, no such stimulus was presented. With no added stimulus, large decreases occurred in the number of runs satisfying the minimum requirement for reinforcement at doses of drug that produced only minimal changes when an added stimulus controlled behavior. Thus, increased stimulus control diminishes the behavioral changes produced by d-amphetamine even when the possible contribution by baseline reinforcement rate is minimized.

Animals↗
PubMed1983

Behavioral detection of 60-Hz electric fields by rats.

Rats partially deprived of food were trained individually to press a lever in the presence of a vertical, 60-Hz electric field and not to press in its absence. Correct detections that occurred during brief, 3- or 4-s trials occasionally produced a food pellet. The probability of detecting the field was found to increase as field strength increased. The threshold of detection, ie, the field strength required for detections at a probability of 0.5 after correction for errors, was generally between 4 and 10 kV/m. The range of field strengths between almost zero and almost 100% correctness of detection was approximately 8 kV/m. A logistic function provided a good description of the increase in the detection probability with increasing field strength. These performances occurred reliably in 19 rats, some of which were studied for 2 years. Control procedures showed that the behavior required that the rat be in the electric field; the behavior was not controlled by any of several potentially confounding variables.

Animals↗
PubMed1983

Behavioral effects of toluene are modulated by stimulus control.

Behavior that is strongly controlled by environmental stimuli is less susceptible to disruption by certain chemicals than is such behavior not under strong external control. To determine whether toluene's effects can also be minimized by environmental stimuli, two varieties of a fixed consecutive number schedule were studied. With one, a lever press response was reinforced with milk only if preceded by a minimum of eight consecutive responses on a second lever, no cues indicating that the minimum number had been reached. With the other, a combination of lights and a tone served as a discriminative stimulus signaling the completion of the minimum response number. In an experiment studying these schedules separately, rats were exposed to toluene concentrations up to 3000 ppm for 4-hr periods immediately before their performance was tested. Toluene reduced the accuracy of both types of behavior in a concentration-related fashion. Clear differential effects occurred, with the signaled behavior, i.e., that under stronger stimulus control, showing less disruption by toluene. Similar results were produced after 2-hr exposures with a multiple schedule in which the signaled and unsignaled performances alternated within a single session. Response rate changes were observed at 560 ppm, but changes in rate were independent of effects on the accuracy of performance. The EC50 for significant behavior disruption was 1081 ppm for the unsignaled component of the multiple schedule; the EC10 was 480 ppm. No performance disruption was observed in the signaled component below 1780 ppm. The finding of differential sensitivity could be useful in guiding the development of more sensitive tests of performance impairment.

Animals↗
PubMed1983

The microanalysis of fixed-interval responding.

The fixed-interval schedule of reinforcement is one of the more widely studied schedules in the experimental analysis of behavior and is also a common baseline for behavior pharmacology. Despite many intensive studies, the controlling variables and the pattern of behavior engendered are not well understood. The present study examined the microstructure and superstructure of the behavior engendered by a fixed-interval 5- and a fixed-interval 15-minute schedule of food reinforcement in the pigeon. Analysis of performance typical of fixed-interval responding indicated that the scalloped pattern does not result from smooth acceleration in responding, but, rather, from renewed pausing early in the interval. Individual interresponse-time (IRT) analyses provided no evidence of acceleration. There was a strong indication of alternation in shorter-longer IRTs, but these shorter-longer IRTs did not occur at random, reflecting instead a sequential dependency in successive IRTs. Furthermore, early in the interval there was a high relative frequency of short IRTs. Such a pattern of early pauses and short IRTs does not suggest behavior typical of reinforced responding as exemplified by the pattern found near the end of the interval. Thus, behavior from clearly scalloped performance can be classified into three states: postreinforcement pause, interim behavior, and terminal behavior.

Journal Article↗
PubMed1982

Neurotoxicity of methylmercury in the pigeon.

Pigeons repeatedly exposed to sublethal doses of methylmercury (5-10 mg Hg/kg/wk, po, for 34-77 days) exhibited marked behavioral changes that were accompanied by only minor evidence of neuropathologic changes at the light microscopic level. Accuracy and rate of pecking for grain declined while food intake remained unchanged. Methylmercury produced permanent changes in posture and in motor coordination. The regional distribution of methylmercury within the nervous system was poorly correlated with the distribution of pathologic changes. Overt behavioral signs appeared after the brain accumulated more than about 12 to 16 ppm Hg. Data with pigeons support earlier evidence that the dose-response function for methylmercury is modulated by dose rate and duration of exposure, since the pattern of blood and tissue distribution of Hg is established in advance of the appearance of signs. The pigeon is more sensitive to methylmercury than are mice and rats, but less sensitive than primates.

Animals↗
PubMed1981

Stimulus control and the effects of d-amphetamine in the rat.

External discriminative stimuli can modify the behavioral effects of d-amphetamine. Previous work with the pigeon has demonstrated that some aspects of performance on the fixed consecutive number schedule are changed less if a discriminative stimulus indicates when reinforcement is available. This effect has now been replicated with the rat using both simple and multiple schedules. Moderate doses of d-amphetamine (0.56--1.0 mg/kg) usually produced large decreases in reinforced runs when no external cue indicated the possibility of reinforcement. Adding discriminative stimuli when the number requirement was met decreased the drug effect. As was true in the pigeon, response rate measures did not differ between the two stimulus control conditions. Thus, external stimulus control diminishes the drug effect in both species, despite the fact that key pecking was studied in the pigeon and lever pressing in the rat. Evidence was also seen of a possible increase in discriminative stimulus control by d-amphetamine.

Animals↗