Karen G Anderson

Karen G Anderson
West Virginia University | WVU · Department of Psychology

Ph.D.

About

47
Publications
3,663
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1,083
Citations
Additional affiliations
August 2003 - present
West Virginia University
Position
  • Professor (Associate)
January 1998 - July 2003
University of Mississippi Medical Center
Position
  • Professor (Assistant)
Education
August 1991 - December 1997
University of Florida
Field of study
  • Psychology

Publications

Publications (47)
Article
Withdrawal from Δ⁹-tetrahyrocannibidol (THC) is associated with a host of dysphoric symptoms that increase probability of relapse. To date, many animal models of THC withdrawal rely on withdrawal-induced somatic withdrawal signs leaving withdrawal-suppressed behavior relatively unexplored. As compared with withdrawal-induced behaviors, ongoing beha...
Article
Individuals with attention-deficit/hyperactivity disorder tend to make risker choices during probabilistic-discounting procedures. Thus, how common attention-deficit/hyperactivity disorder medications affect probabilistic discounting is of interest. In general, d-amphetamine increases risk-taking while atomoxetine has produced mixed effects in rats...
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Full-text available
In two experiments, the role of the response-reinforcer relation in maintaining low-rate responding under unsignaled delay conditions was investigated. In both experiments pecking by pigeons on one response key, denoted the relevant key, was reinforced under an unsignaled delay-of-reinforcement procedure (defined as tandem variable-interval (VI) di...
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Traumatic brain injury (TBI) affects 2.8 million people annually in the United States, with significant populations suffering from ongoing cognitive dysfunction. Impairments in decision-making can have major implications for patients and their caregivers, often enduring for years to decades, yet are rarely explored in experimental TBI. In the curre...
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Impulsive choice underlies several psychological disorders and can be assessed in laboratory rats using delay-discounting tasks, in which choice is for either one food pellet immediately or three food pellets after a delay. Choice for the smaller, immediate reinforcer is considered the impulsive choice. Lewis (LEW) and Fischer 344 (F344) rats diffe...
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RationaleNicotine acts as an agonist for nicotinic acetylcholine receptors (nAChRs), and mecamylamine, a nonselective nAChR antagonist, attenuates effects of nicotine on delay discounting in some rat strains; whether nicotine’s attenuation is specific to nAChR antagonism is unknown. Objective During experiment 1, we evaluated dose-dependent effects...
Article
Impulsive choice in humans can be altered by changing reinforcer magnitude; however, this effect has not been found in rats. Current levels of impulsive choice can also influence effects of d-amphetamine. This study used a within-subject assessment to determine if impulsive choice is sensitive to changes in reinforcer magnitude, and whether effects...
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In delay discounting, choice is between two reinforcers that differ in amount and delay, and the subjective value of either reinforcer decreases as a function of delay to its receipt. The steepness of the discounting function is thought to reflect the degree of impulsive choice. Many factors can influence impulsive choice, including the addition of...
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Full-text available
Impulsive choice is often examined using a delay-discounting procedure, where there is a choice between two reinforcers of different magnitudes presented at varying delays. Individual discounting rates can be influenced by many factors including strain differences and drug effects. Lewis (LEW) and Fischer 344 (F344) rats have behavioral and neuroch...
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Studies concerning the relation between stimulant drug exposure and subsequent delay discounting (impulsive choice) have resulted in mixed findings that could be related to the type of stimulant drug exposure or the use of between-subject comparisons. The purpose of the present study was to examine effects of prior D-amphetamine exposure on subsequ...
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Impulsive choice is correlated with behavioral problems such as attention-deficit/hyperactivity disorder and substance abuse. Effects of stimulant drug administration on impulsive choice are not consistent and may depend on baseline differences in impulsive choice. A within-session delay-discounting procedure in which choice was between one food pe...
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Stimulant drugs have been shown either to increase or decrease rates of delay discounting (impulsive choice). These mixed findings may result from genetic, neurochemical, or environmental factors. Lewis (LEW) and Fischer 344 (F344) rats have neurochemical and behavioral differences that may be relevant to delay discounting and were used to examine...
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The prenatally stressed (PS) rat shows enhanced conditioned fear and increased behavioral inhibition in response to footshock compared to control (CON) rats. It is unclear whether this facilitated learning will occur only with aversive stimulation, or if it will also be observed in the context of positive reinforcement. There are limited and incons...
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Methylphenidate (MPH) is one of the most common therapeutics used for the treatment of attention-deficit/hyperactivity disorder (ADHD), which consists of symptoms of inattention, and/or impulsivity and hyperactivity. Acute administration of MPH has been found to decrease impulsive choice in both humans and nonhuman animals, however, little is known...
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Biological differences may underlie individual differences in impulsive behavior, such as choice for a smaller, more immediate reinforcer over a larger, more delayed reinforcer. Repeated exposure to drugs of abuse may have different effects on such behavior. To evaluate the acute and repeated effects of nicotine on impulsive choice, two strains of...
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One common procedure for obtaining delay-discounting functions consists of a choice between a larger reinforcer that is presented after an increasing delay and a smaller reinforcer that is always presented immediately within session. Repeating the same context of delay presentation (e.g. ascending delay order) in a discrete-choice paradigm, however...
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Kava is a widely available and used herbal medicine that is not regulated in many countries. There are many questions concerning kava's stimulus properties, potential for therapeutic use, and potential for abuse. Although there is evidence that kava may possess some anxiolytic properties, kava's mechanism of action and the extent to which it may se...
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Delay to presentation is one variable that can weaken the reinforcing efficacy of an outcome in a choice situation and drugs have been shown to modify such choices. A growing body of literature has examined effects of stimulant drugs on temporal (delay) discounting, but effects of caffeine, the most widely used stimulant in the world, have not prev...
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Previous work has shown neurochemical and behavioral differences between Lewis rats and Fischer 344 rats. Some of this work suggests that there might be differential sensitivity to delayed reinforcement between the two strains. To further explore this possibility, Lewis (n=8) and Fischer 344 (n=8) rats were exposed to a response-acquisition task wi...
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Although a delay between behavior and reinforcer has been shown to weaken behavior, little is known about the effects of delay on drug choice. The present study examined effects of delay between lever press and reinforcer presentation on the choice between a drug and non-drug reinforcer and between different drug doses. Monkeys (n=4) were allowed t...
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Convergent lines of evidence support a dual deficit model of stimulant withdrawal, where reductions in synaptic dopamine (DA) and 5-hydroxytryptamine (serotonin) (5-HT) contribute to dysphoria, drug craving, and relapse. Thus, we predicted that a nonamphetamine compound with substrate activity at DA and 5-HT transporters (i.e., a dual DA/5-HT relea...
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It has been reported that among drugs with mixed actions on central nervous system monoamine systems, increased serotonergic activity is associated with decreased potency as a reinforcer. The present experiment was designed to examine this relationship for amphetamine analogs that varied in serotonin releasing potency and to evaluate whether seroto...
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Rates of delay discounting (impulsive choice) have been shown to vary among individuals, particularly people who abuse drugs relative to those who do not, but factors that may contribute to these differences have not been identified. To explore a role for possible genetic and neurochemical determinants, Lewis (n = 8) and Fischer 344 (n = 8) rats we...
Article
Drug abuse can be characterized as a condition in which the choice to self-administer a drug is excessive, even exclusive of the choice of other reinforcers. Under concurrent interval schedules of reinforcement, subjects typically distribute behavior to match reinforcement allocation. However, research has shown that when behavior is maintained by...
Article
Drug abuse is often considered a problem related to impulse-control disorders, but little is known about the factors that determine the choice to self-administer a drug in a self-control/impulsivity paradigm. The objective of the present study was to evaluate choice between a low dose of cocaine administered after a relatively short delay (impulsiv...
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The generalized matching law predicts that the relative rate of behavior maintained by different reinforcers will match the relative rate of reinforcement. It has previously been shown that responding maintained by either food deliveries or cocaine injections under concurrent variable-interval (conc VI) schedules is well described by the generalize...
Article
Ephedrine is a sympathomimetic drug that is currently found in many over-the-counter preparations. This compound exists as four isomers which, in addition to a racemic mixture, were evaluated for their positive reinforcing effects and for their similarity to (+)-amphetamine as a discriminative stimulus. Rhesus monkeys (N=3) with intravenous cocaine...
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The neuronal actions of methamphetamine (MA) include an increase in extracellular levels of monoamines, presumably via reverse transport involving the monoamine transporters. This action is thought to play an important role in the effects of MA. Therefore, in the present experiment, it was hypothesized that a monoamine uptake blocker would block be...
Article
Rationale: The neuronal actions of methamphetamine (MA) include an increase in extracellular levels of monoamines, presumably via reverse transport involving the monoamine transporters. This action is thought to play an important role in the effects of MA. Therefore, in the present experiment, it was hypothesized that a monoamine uptake blocker wou...
Article
It has previously been shown that self-administration of cocaine under concurrent variable-interval schedules is well described by the generalized matching law. That is, choice between two cocaine-maintained options was apportioned in accordance with relative frequency of reinforcement. However, the generality of this conclusion to drugs of other p...
Article
Male and female rats were trained to discriminate 10.0 mg/kg cocaine from saline in a two-lever discrimination task. Injection-appropriate responding was reinforced by food pellet presentation on a tandem random-interval 30-s fixed-ratio 10 schedule. Generalization testing was conducted in extinction 10 min following an injection of saline, 1.0, 3....
Article
Previously, sex differences have been observed in the behavioral effects of acute and chronic cocaine administration. In the present experiment, male and female rats were trained to discriminate intraperitoneal injections of 10.0 mg/kg cocaine from its vehicle. It was hypothesized that the subjective effects of cocaine might differ between male and...
Article
Identification of nicotinic receptor subtypes involved in nicotine dependence is required for guiding the design of more selective antagonists capable of blocking the nicotine cue and nicotine self-administration. Due to the multiplicity of nicotinic receptors in the mammalian brain, selective agonists and antagonists are needed to assess the funct...
Article
Five male Wistar rats were exposed to a two- component multiple schedule. In one component, signaled by a tone, food pellets were presented on a random-time 120-s schedule. In the other component, food pellets were presented on a random-time 30-s schedule. Pellets were only presented during a 10-s time-in period that alternated with a 50-s time-out...
Article
Gender differences in anxiety have long been assumed to exist, but the experimental evidence is contradictory. It has also been suggested that antianxiety agents may have gender-dependent behavioral effects. The present experiment was designed to establish whether or not intact male and female rats behave differently when exposed to a Differential-...
Article
Tail-tip plasma samples of intact and gonadectomized male and female Wistar rats were analyzed for cocaine and benzoylecgonine. The samples were obtained from immobilized subjects 10 and 30 min following the 1st and 22nd intraperitoneal injections of 10 mg/kg cocaine hydrochloride. Gender differences in plasma cocaine or benzoylecgonine levels were...
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Full-text available
Male Wistar rats were exposed to a two-component multiple schedule: a random-interval 30 s schedule of pellet presentation and a conjoint random-interval 30 s schedule of pellet presentation, random-interval 2 s schedule of timeout 10 s presentation. Once responding had stabilized subjects were injected intraperitoneally with vehicle, chlordiazepox...
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Full-text available
Intact and gonadectomized male and female rats pressed a lever to obtain food on different fixed-ratio (FR) schedules in a three-component multiple schedule. The values of a small, intermediate and large FR schedule were individually determined and were higher for intact male rats than for most subjects in the other groups. Acute cocaine administra...
Article
Intact and gonadectomized male and female rats pressed a lever to obtain food on different fixed-ratio (FR) schedules in a three-component multiple schedule. The values of a small, intermediate and large FR schedule were individually determined and were higher for intact male rats than for most subjects in the other groups. Acute cocaine administra...
Article
Three male and three female Wistar rats pressed a lever on a fixed-interval 60-s schedule of food reinforcement while they had simultaneous access to an alcohol solution. They were challenged with different doses of cocaine hydrochloride (vehicle, 1, 3, 10, and 30 mg/kg) once lever press rates and lick rates had stabilized. Low doses of cocaine (1...
Article
Six female and five male Wistar rats obtained food by pressing a lever on a fixed-interval (FI) 60-s schedule in the presence of a sipper tube which allowed access to an alcohol solution. Systematic manipulation of the alcohol concentration revealed that male rats consumed higher alcohol concentrations (v/v) than female rats to obtain maximum alcoh...
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Typescript. Thesis (Ph. D.)--University of Florida, 1998. Vita. Includes bibliographical references (leaves 163-168).
Article
Full-text available
Typescript. Thesis (M.S.)--University of Florida, 1995. Vita. Includes bibliographical references (leaves 20-22).

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