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Results 251 - 300 of 1395
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Le Bourg Eric - - 2005
The learned suppression of photopositive tendencies was studied at the individual level in young flies of both sexes. In a T-maze, flies had to choose between an arm leading to a lighted vial associated with an aversive stimulus (i.e., a solution of quinine chlorhydrate deposited on a filter paper in ...
Weidemann Gabrielle - - 2005
Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CS; e.g., tone), the pairing of an orthogonal stimulus from another modality (e.g., light) with the unconditioned stimulus (US) results in strong recovery of responding to the extinguished CS. This recovery occurred to about an equal degree regardless ...
McClure E A - - 2005
Two experiments used a matching to sample of durations procedure to examine changes in temporal discrimination evoked by D-amphetamine (0.75, 1.50, 2.25 and 3.0 mg/kg i.m.) in pigeons. Responses to one key color were reinforced after long (8-s) stimuli: responses to the alternative key color were reinforced after short (2-s) ...
Shahan Timothy A - - 2005
The effects of rate of conditioned reinforcement on the resistance to change of operant behavior have not been examined. In addition, the effects of rate of conditioned reinforcement on the rate of observing have not been adequately examined. In two experiments, a multiple schedule of observing-response procedures was used to ...
Jovanovic Tanja - - 2005
BACKGROUND: The inability to suppress excessive fear or anxiety is a significant clinical problem. In the laboratory, extinction is a preferred method for the study of fear inhibition; however, in this paradigm the same stimulus causes both elicitation (excitation) and inhibition of fear, making it difficult to know whether an ...
Bremner J Douglas JD Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30306, USA. - - 2005
In the conditioned fear paradigm, repeated pairing of an aversive unconditioned stimulus (US) (e.g. electric shock) with a neutral conditioned stimulus (CS) (e.g. bright light) results in a conditioned fear response to the light alone. Animal studies have shown that the amygdala plays a critical role in acquisition of conditioned ...
Eiler William J A WJ 2nd Psychobiology of Addictions Program, Department of Psychology, Indiana University-Purdue University, Indianapolis, Indiana 46202-3275, - - 2005
The relation between ethanol (EtOH) preference and sensitivity to brain stimulation reward (BSR) was examined under multiples schedules of reinforcement in the current study. For comparison, the study also examined the relation between EtOH preference and motivation for a sweet, palatable sucrose solution under similar schedules of reinforcement. To investigate ...
Cassaday Helen J - - 2005
Haloperidol has been shown to enhance attentional selectivity in conditioning procedures. For example, in latent inhibition (LI) it improves animals' ability to treat as irrelevant, stimuli that have previously been presented without consequence. The present study tested whether this finding would generalize to other procedures that present animals with weak ...
Stockhorst Ursula - - 2005
PURPOSE OF REVIEW: Classical conditioning is a form of associative learning, based on the pioneering work of I. P. Pavlov: due to its association with an unconditioned stimulus that induces an unconditioned response, an initially neutral stimulus will become a conditioned stimulus evoking a conditioned response in the absence of ...
Belke Terry W - - 2005
Habituation appears to play a role in the decline in wheel running within an interval. Aoyama and McSweeney [Aoyama, K., McSweeney, F.K., 2001. Habituation contributes to within-session changes in free wheel running. J. Exp. Anal. Behav. 76, 289-302] showed that when a novel stimulus was presented during a 30-min interval, ...
Wade-Galuska Tammy - - 2005
Four rats obtained food by pressing a lever 30 times in each component of a two-component multiple schedule. Across conditions, the force required to press the lever was increased in one component and held constant in the other. Pausing at the outset of each component was controlled by both the ...
Miki Andrew - - 2005
Pigeons were trained in a within-subjects design to discriminate durations of a filled interval (2 s and 8 s of light) and durations of an empty interval (2 s and 8 s bound by two 500-ms light markers). Filled intervals required a response to one set of comparisons (e.g., blue ...
Reed Phil - - 2005
Response rates under random-interval schedules are lower when a brief (500 ms) signal accompanies reinforcement than when there is no signal. The present study examined this signaled-reinforcement effect and its relation to resistance to change. In Experiment 1, rats responded on a multiple random-interval 60-s random-interval 60-s schedule, with signaled ...
Drew Michael R - - 2005
The peak procedure was used to characterize response timing during acquisition and maintenance of conditioned responding in goldfish. Subjects received light-shock pairings with a 5- or 15-s interstimulus interval. On interspersed peak trials, the conditioned stimulus light was presented for 45 s and no shock was delivered. Peaks in the ...
Grondin Simon - - 2005
We investigated how does the structure of empty time intervals influence temporal processing. In experiment 1, the intervals to be discriminated were the silent durations marked by two sensory signals, both lasting 10 or 500 ms; these signals were two identical flashes (intramodal: VV), or one visual flash (V) followed ...
Köksal Falih - - 2004
An animal model of sexual fetishism was developed with male Japanese quail based on persistence of conditioned sexual responding during extinction to an inanimate object made of terrycloth (Experiments 1 and 3). This persistent responding occurred only in subjects that came to copulate with the terrycloth object, suggesting that the ...
Urushihara Kouji - - 2004
Four experiments were conducted to examine appetitive backward conditioning in a conditioned reinforcement preparation. In all experiments, off-line classical conditioning was conducted following lever-press training on two levers. Presentations of a sucrose solution by a liquid dipper served as an unconditioned stimulus (US) and two auditory stimuli served as conditioned ...
Toole Lisa M - - 2004
Charlop, Burgio, Iwata, and Ivancic [J. Appl. Behav. Anal. 21 (1988) 89] demonstrated that varied punishment procedures produced greater or more consistent reductions of problem behavior than a constant punishment procedure. More recently, Fisher and colleagues [Res. Dev. Disabil. 15 (1994) 133; J. Appl. Behav. Anal. 27 (1994) 447] developed ...
Troncoso Julieta - - 2004
The murine vibrissae sensorimotor system has been scrutinized as a target of motor learning through trace classical conditioning. Conditioned eyelid responses were acquired by using weak electrical whisker-pad stimulation as conditioned stimulus (CS) and strong electrical periorbital stimulation as unconditioned stimulus (US). In addition, conditioned vibrissal protraction was obtained pairing ...
Weidemann Gabrielle - - 2004
Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CSA--e.g., tone), the pairing of a novel, cross-modal stimulus (CSB--e.g., light) with the unconditioned stimulus (US) results in strong recovery of responding to the extinguished CSA. Experiment 1 demonstrated that the recovery of responding to CSA is not ...
Ajay Sriram M - - 2004
Stimulus reinforcement strengthens learning. Intervals between reinforcement affect both the kind of learning that occurs and the amount of learning. Stimuli spaced by a few minutes result in more effective learning than when massed together. There are several synaptic correlates of repeated stimuli, such as different kinds of plasticity and ...
Madden Gregory J GJ Department of Psychology, University of Wisconsin, Eau Claire, WI 54702-4004, USA. - - 2004
Prior studies comparing discounting of delayed hypothetical or potentially real rewards have reported no differences, but they used within-subjects designs. This raises the possibility that participants remembered their choices in one condition and repeated them in the other. In Experiment 1, between-subjects comparisons were made with an adjusting-amount procedure. No ...
Hinderliter Charles F - - 2004
Conditioned taste aversion can be acquired when rats experience an unconditioned stimulus (US) while anesthetized. In contrast to anesthetics, a hypothermia-induced comatose state immediately after presentation of a taste conditioned stimulus (CS) prevented a taste-illness association at relatively short CS-US intervals and potentiated the aversion at longer intervals. Results at ...
Blair C A J - - 2004
Rats received exposure to 3 flavor compounds, AX and BX, presented in alternation, and CX, presented on a separate block of trials. The hypothesis that this treatment would leave B effectively more salient than C was tested in 3 ways. Experiment 1 showed that the unconditioned response evoked by B ...
Crowley Michael A - - 2004
Choice typically is studied by exposing organisms to concurrent variable-interval schedules in which not only responses controlled by stimuli on the key are acquired but also switching responses and likely other operants as well. In the present research, discriminated key-pecking responses in pigeons were first acquired using a multiple schedule ...
Dirikx Trinette - - 2004
The present study investigated reinstatement of conditioned responses in humans by using a differential Pavlovian conditioning procedure. Evidence for reinstatement was established in a direct (fear rating) and in an indirect measure (secondary reaction time task) of conditioning. Moreover, the amount of reinstatement in the secondary reaction time task was ...
Knight David C DC University of Wisconsin, Milwaukee, Wisconsin 53201, - - 2004
Previous functional magnetic resonance imaging (fMRI) studies have characterized brain systems involved in conditional response acquisition during Pavlovian fear conditioning. However, the functional neuroanatomy underlying the extinction of human conditional fear remains largely undetermined. The present study used fMRI to examine brain activity during acquisition and extinction of fear conditioning. ...
Lazareva Olga F - - 2004
Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These ...
Kehoe E James - - 2004
Rabbits were given reinforced training of the nictitating membrane (NM) response using separate conditioned stimuli (CSs), which were a tone, light, and/or tactile vibration. Then, two CSs were compounded and given further pairings with the unconditioned stimulus (US). Evidence of both overexpectation and summation effects appeared. That is, responding to ...
Espinet Alfredo - - 2004
In two experiments rats were preexposed to neutral stimuli. Both experiments used a between-subjects design in which a paired group was preexposed to intermixed presentations of A --> Band AX, and an unpaired control group was preexposed to intermixed presentations of A, B, and AX. After the conditioning of B, ...
McSweeney Frances K - - 2004
The experiments tested the idea that changes in habituation to the reinforcer contribute to behavioral interactions during multiple schedules. This idea predicts that changing an aspect of the reinforcer should disrupt habituation and produce an interaction. Pigeons and rats responded on multiple variable interval variable interval schedules. Introducing variability into ...
Blough Donald S - - 2004
In three experiments with pigeons, the similarity of unreinforced test stimuli to a reinforced stimulus and the frequency of reinforcement associated with a stimulus were varied. The stimulus on each trial was a small spot that appeared in different hues or, in Experiment 3, different forms. Differential response frequency and ...
Baldi Elisabetta - - 2004
The relationship between US (footshock) intensity and the two conditioned freezing responses (to acoustic CS and to "context") was investigated in fear conditioning. Administered footshock intensity was 0.00, 0.15, 0.30, 0.60, 0.90, and 1.20 mA to six different groups of 70-day-old male Albino Wistar rats. To measure contextual freezing, the ...
Callen Edward J - - 2004
According to the effective reinforcement theory of avoidance learning, there is a positive relationship between the level of context fear and the effectiveness of feedback stimuli. The present research used different preexposure treatments to manipulate context fear and to evaluate the effects of feedback stimuli in two-way avoidance learning. Rat ...
Wilson David I G - - 2004
RATIONALE: Second-order schedules of reinforcement have been used extensively to model reward-seeking and drug-seeking behaviour. Second-order stimuli within second-order schedules have been shown to enhance response rates during operant responding for natural reinforcers and drug reinforcers. This has led some to view second-order schedules of drug reinforcement as a model ...
Lindquist Derick H - - 2004
Auditory information can reach the lateral nucleus of the amygdala (LA) through a monosynaptic thalamic projection or a polysynaptic cortical route. The polymodal input from the perirhinal cortex (PR) is a major informational gateway to the LA and nearby structures. Pretraining PR lesions impair fear conditioning to a context, but ...
McSweeney Frances K - - 2004
The experiment tested for stimulus specificity in extinguished operant responding. Eight pigeons pecked keys for food reinforcers delivered by a variable interval (VI) 60-s schedule. The key was illuminated with red light during some sessions and white light during others. Then, responding was placed on extinction. During some sessions of ...
Wiedenmayer Christoph P - - 2004
The experience of a single threatening situation may alter the behavior of an animal in a long-lasting way. Long-lasting changes in behavior have been induced in laboratory animals to model and investigate the development and neural substrate of human psychopathologies. Under natural conditions, however, changes in behavior after an aversive ...
Nakahara Hiroyuki H Lab for Mathematical Neuroscience, RIKEN Brain Science Institute, Wako, Saitama, Japan. - - 2004
Midbrain dopamine (DA) neurons are thought to encode reward prediction error. Reward prediction can be improved if any relevant context is taken into account. We found that monkey DA neurons can encode a context-dependent prediction error. In the first noncontextual task, a light stimulus was randomly followed by reward, with ...
Winn Gary L GL Industrial and Management Systems Engineering, West Virginia University, PO Box 6070, Morgantown, WV 26506-6070, USA. - - 2004
Safety literature confirms that incentives such as money or sunglasses seem to improve safety conditions over the short run. However, no studies could be found which tested the effect of incentives on fall protection for a period longer than a few days. In our research we found that after 6 ...
Knight David C - - 2003
Conditional responding during simple Pavlovian conditioning is often characterized as a form of implicit memory. The extent to which this type of associative learning is independent of awareness is an issue of continuing debate. Previous studies have demonstrated conditioning in the absence of awareness. However, their results have been questioned ...
Cunningham Christopher L - - 2003
RATIONALE: Although the distinction between "biased" and "unbiased" is generally recognized as an important methodological issue in place conditioning, previous studies have not adequately addressed the distinction between a biased/unbiased apparatus and a biased/unbiased stimulus assignment procedure. Moreover, a review of the recent literature indicates that many reports (70% of ...
Goto Kazuhiro - - 2004
When humans process visual stimuli, global information often takes precedence over local information. In contrast, some recent studies have pointed to a local precedence effect in both pigeons and nonhuman primates. In the experiment reported here, we compared the speed of acquisition of two different categorizations of the same four ...
Krank Marvin D - - 2003
BACKGROUND: Conditioned incentive theories of addictive behavior propose that cues signaling a drug's reinforcing effects activate a central motivational state. Incentive motivation enhances drug-taking and drug-seeking behavior. We investigated the behavioral response to cues associated with ethanol and their interaction with operant self-administration of ethanol. METHODS: In two experiments, rats ...
Masson Sueli - - 2003
Consistent evidence has shown that learning may be produced in paradigms using electrical stimulation of the inferior colliculus as unconditioned stimulus (US). Much evidence has also been provided for the involvement of dopamine in the setting up of adaptive responses to aversive states generated at this mesencephalic level. The aim ...
Sole Leslie M LM University of Toronto, Toronto, Ontario, - - 2003
Pigeons classified a display of illuminated pixels on a touchscreen as sparse or dense. Correct responses were reinforced with six food pellets; incorrect responses were unreinforced. On some trials an uncertain response option was available. Pecking it was always reinforced with an intermediate number of pellets. Like monkeys and people ...
Sargisson Rebecca J - - 2003
Pigeons were trained in a matching-to-sample procedure with retention intervals of 0, 2, 4, 6, and 8 s mixed within each session. In different conditions, reinforcement was delayed by 0, 1, 2, 4, 6, or 8 s from correct choice responses. Discriminability decreased with increasing retention-interval duration and with increasing ...
Waddell Jaylyn - - 2003
Though much is known about the neural circuits involved in the elicitation of fear, little is known about the neural circuits responsible for the reduction of fear. The present experiments investigated the contribution of the superior colliculus (SC) and the dorsal periacquaductal gray (dPAG) in the reduction of conditioned fear ...
Landon Jason - - 2003
Five pigeons were trained on pairs of concurrent variable-interval schedules in a switching-key procedure. The arranged overall rate of reinforcement was constant in all conditions, and the reinforcer-magnitude ratios obtained from the two alternatives were varied over five levels. Each condition remained in effect for 65 sessions and the last ...
Reed Phil - - 2003
Four experiments examined the effect on rats' response rate of presenting a brief (500 ms) stimulus simultaneously with the delivery of food on fixed-interval (FI) schedules. In Experiment 1, reinforcement signals that were spatially diffuse (both tones and lights) elevated rates of responding, but responding was attenuated by localized visual ...
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