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Results for “Conditioning, Operant”

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PubMed1992

Operant conditioning of P300.

This study demonstrates that operant conditioning may increase the P300 component of the event-related potential above a level obtained without contingent training. An experimental group of subjects was rewarded for producing large P300 amplitudes and was compared with a yoked control group which was rewarded on a random basis. During training the experimental subjects increased both the amplitude of the P300 and of a subsequent frontal negative slow wave relative to the control group. These training effects were independent of prestimulus potential shifts and occurred likewise for target and nontarget stimuli.

Adult↗

PubMed1984

Operant conditioning and the modulation of cardiovascular function.

Operant learning appears to be one of the primary mechanisms underlying what cardiovascular and pulmonary physiologists have called adaptation, habituation, and central command. In general, studies that have attempted to use operant conditioning alone to create experimental models of behaviorally induced disease have been unsuccessful because the cardiovascular responses adapted or habituated over time. Thus, these studies have provided implicit demonstrations of the roles played by CNS and conditioning processes in achieving and preserving homeostasis. During the past few years those interested in behavioral contributions to cardiovascular pathology have therefore begun to look at interactions between behavior and other variables that might predispose organisms towards pathology (e.g. genetic background; excessive sodium intake). Perhaps even more promising has been the growth in the number of technically competent, well-controlled studies designed to investigate: (a) broad scientific questions of how behaviorally important processes such as learning and reinforcement interact with physiologically important variables such as blood flow redistribution and cardio-pulmonary integration; and (b) the role of behavioral variables in CNS control of the circulation. Based upon our survey of the recent literature, we believe that the time is ripe for those interested in cardiovascular neurobiology increasingly to include behavioral variables in their studies, because the raison d'etre of the CNS is to optimize the organism's ability to interact with its environment. Only when these organismic-environmental interactions are studied both behaviorally and physiologically, in a broad biological context, will it be possible to develop rational models of neuro-circulatory regulation.

Animals↗

PubMed2006

Drinking water biofilm assessment of total and culturable bacteria under different operating conditions.

Monitoring of biofilms subjected to different operating conditions was performed using a flow cell system. The system was fed by chlorine-free tap water, with and without added nutrients (0.5 mg l(-1) carbon, 0.1 mg l(-1) nitrogen and 0.01 mg l(-1) phosphorus), and biofilms were grown on polyvinyl chloride (PVC) and stainless steel (SS) coupons, both in laminar and turbulent flow. The parameters analysed were culturable cells, using R2A, and total bacteria, which was assessed using the 4,6-diamino-2-phenylindole (DAPI) staining method. The impact of the different operating conditions in the studied parameters was established using Multivariate Analysis of Variance (MANOVA). From the most relevant to the least relevant factor, the total and culturable bacteria in biofilms increased due to the addition of nutrients to water (F = 20.005; p < 0.001); the use of turbulent (Re = 11000) instead of laminar (Re = 2000) hydrodynamic flows (F = 9.173; p < 0.001); and the use of PVC instead of SS as the support material (F = 2.848; p = 0.060). Interactions between these conditions, namely between surface and flow (F = 8.235; p < 0.001) and also flow and nutrients (F = 5.498; p < 0.05) have also proved to significantly influence biofilm formation. This work highlights the need for a deeper understanding of how the large spectrum of conditions interact and affect biofilm formation potential and accumulation with the final purpose of predicting the total and culturable bacteria attached to real drinking water distribution pipes based on the system characteristics.

Biofilms↗

PubMed1989

Operant conditioning of head-waving in Aplysia. III. Cellular analysis of possible reinforcement pathways.

Operant conditioning of the head-waving response in Aplysia, as well as conditioning of the electrical activity of identified neck muscles, can be induced readily when bright light is used as aversive reinforcement (Cook and Carew, 1986, 1989b). A cellular analysis of this type of operant conditioning requires an understanding of the neural circuitry that underlies the reinforcement pathways involved in the conditioning. In the present paper we describe a cellular analysis of possible reinforcement pathways that mediate the aversive effects of bright light in the CNS of Aplysia. Using a semi-intact "split-body" preparation, we explored the effects of bright light on the operant response pathway by recording intracellularly from identified pedal neck and body wall motor neurons, which contribute to the operant response. In these experiments we identified 2 light-sensitive pathways. One pathway, from the eyes and rhinophores, mediated functional inhibition of light-induced excitation of pedal motor neurons. The other pathway, from the oral veil (cerebral ganglion nerves C1-C3) mediated significant excitation of the same motor cells. Randomly occurring blank trials ruled out the possibility that the light-induced effects were due to sampling bias. Finally, surgical isolation of the CNS from the periphery showed that none of the effects of light were due to direct illumination of central neurons. This identification of candidate reinforcement pathways will facilitate a cellular analysis of operant conditioning of head-waving in Aplysia.

Animals↗

PubMed2003

Operant conditioning in invertebrates.

Learning to anticipate future events on the basis of past experience with the consequences of one's own behavior (operant conditioning) is a simple form of learning that humans share with most other animals, including invertebrates. Three model organisms have recently made significant contributions towards a mechanistic model of operant conditioning, because of their special technical advantages. Research using the fruit fly Drosophila melanogaster implicated the ignorant gene in operant conditioning in the heat-box, research on the sea slug Aplysia californica contributed a cellular mechanism of behavior selection at a convergence point of operant behavior and reward, and research on the pond snail Lymnaea stagnalis elucidated the role of a behavior-initiating neuron in operant conditioning. These insights demonstrate the usefulness of a variety of invertebrate model systems to complement and stimulate research in vertebrates.

Animals↗

PubMed2002

The role of operant conditioning in chronic pain: an experimental investigation.

The role of operant conditioning for the development and maintenance of chronic pain was examined in 30 chronic back pain patients (CBP) and 30 matched healthy controls. Half of each group was reinforced for increased, half for decreased pain reports while EEG, EOG, heart rate, skin conductance and muscle tension levels were recorded. Both groups showed similar learning rates, however, the CBP patients displayed slower extinction of both the verbal and the cortical (N150) pain response. In addition, the CBP group displayed prolonged elevated electromyogram levels to the task. These data suggest that CBP patients are more easily influenced by operant conditioning factors than healthy controls and this susceptibility may add to the maintenance of the chronic pain problem.

Adult↗

PubMed1987

Infant temperament and subject loss due to crying during operant conditioning.

Infants who failed to complete a 2-day operant-conditioning task were compared with a stratified random sample of those who did on measures of infant temperament and several demographic characteristics. A discriminant-function analysis revealed that female infants who cried differed from female infants who did not cry on measures of duration of orienting and latency to approach sudden or novel stimuli. Reliable prediction of crying and noncrying could not, however, be made for males. No sex differences emerged in the incidence of crying or in the number of sessions completed. Partially successful females (i.e., those completing 1 of the 2 sessions) could reliably be discriminated from those who cried during the first session on measures of age at testing and maternal ratings of smiling behavior. The results of this study suggest that, as with habituation studies, subject loss in operant-conditioning studies is influenced by individual differences among the infants which may or may not adversely affect external validity.

Conditioning, Operant↗

PubMed1979

Operant conditioning of vertical eye movements without visual feedback in the midpontine pretrigeminal cat.

An operant conditioning of vertical eye movements was achieved in the midpontine pretrigeminal cat in total darkness by contingent reinforcement of spontaneous eye movements with lateral hypothalamic (LHT) reward stimulation, when each movement (upward direction was chosen in this experiment) exceeded a preset amplitude. However, the response rates in the dark were lower than those in the light and the time to reach the peak response rate was much longer. Recording of evoked potentials to optic chiasma (OC) stimulation revealed enhancement of late components of the visual cortex (VC) and superior colliculus (SC) responses in relation to eye movements. Sequential records of the averaged evoked responses associated with eye movements indicated that the amplitudes of the late components of the VC and SC waves gradually increased in the course of establishment of the operant conditioning, and decreased gradually during extinction. In a yoked control test, increase in amplitudes of the late components was much less significant during non-contingent reinforcement given independently of the eye movements. These results suggest that 'corollary discharge' may play a critical role as a cue in acquisition of the operant conditioning of vertical eye movements when visual feedback is absent in total darkness.

Animals↗

PubMed2004

The optimum operational condition of membrane bioreactor (MBR): cost estimation of aeration and sludge treatment.

A methodology to obtain the most economical operational condition of membrane bioreactor (MBR) is developed. In order to achieve the optimum design parameters of MBR with which operational costs are minimized, aeration and sludge treatment costs were estimated for various operational conditions. Generally sludge treatment cost and aeration cost were inversely proportional to each other, which means sludge treatment cost is minimized when aeration cost is maximized and vice versa. Therefore, there might exist an optimum point between the two extreme cases. However, sludge treatment cost turned out to overwhelm the aeration cost over the reasonable operational conditions. Therefore, sludge minimization was considered to be a key for the economical operation of MBR. In the case of typical municipal wastewater of which COD was 400mgL(-1), steady-state MLSS was expected to increase from 11,000 to 15,000mg/L without sludge removal when HRT was decreasing from 16 to 12h. For the range of operational conditions considered in this study, economically optimum HRT and target MLSS were turned out to be 16h and 11,000mg/L, respectively. Under this condition, aeration for the biodegradation of organic matters would be 13.3m(3) air/min when influent was 1000m(3)/day.

Biodegradation, Environmental↗

PubMed1999

In vitro analog of operant conditioning in aplysia. II. Modifications of the functional dynamics of an identified neuron contribute to motor pattern selection.

Previously, an analog of operant conditioning was developed using the buccal ganglia of Aplysia, the probabilistic occurrences of a specific motor pattern (i.e., pattern I), a contingent reinforcement (i.e., stimulation of the esophageal nerve), and monotonic stimulation of a peripheral nerve (i.e., n.2,3). This analog expressed a key feature of operant conditioning (i.e., selective enhancement of the probability of occurrence of a designated motor pattern by contingent reinforcement). In addition, the training induced changes in the dynamical properties of neuron B51, an element of the buccal central pattern generator. To gain insights into the neuronal mechanisms that mediate features of operant conditioning, the present study identified a neuronal element that was critically involved in the selective enhancement of pattern I. We found that bursting activity in cell B51 contributed significantly to the expression of pattern I and that changes in the dynamical properties of this cell were associated with the selective enhancement of pattern I. These changes could be induced by an explicit association of reinforcement with random depolarization of B51. No stimulation of n.2,3 was required. These results indicate that the selection of a designated motor pattern by contingent reinforcement and the underlying neuronal plasticity resulted from the association of reinforcement with a component of central neuronal activity that contributes to a specific motor pattern. The sensory stimulus that allows for occurrences of different motor acts may not be critical for induction of plasticity that mediates the selection of a motor output by contingent reinforcement in operant conditioning.

Animals↗

PubMed1995

Operantly conditioned plasticity and circadian rhythm in rat H-reflex are independent phenomena.

Recent studies indicate that rats can increase or decrease H-reflex amplitude in response to an operant conditioning paradigm. In addition, rats also display a circadian rhythm in H-reflex amplitude. As part of the development of H-reflex conditioning in the rat as a new model for defining the plasticity underlying a simple form of learning, this study examined the relationship in the rat between operantly conditioned H-reflex change and the H-reflex circadian rhythm. When H-reflex amplitude increased or decreased in response to the operant conditioning program, its circadian rhythm showed no changes in phase and minimal change in amplitude. Furthermore, animals did not alter daily performance schedule so as to use the rhythm to increase reward probability. Thus, in the rat, H-reflex operant conditioning and the H-reflex circadian rhythm appear to be independent phenomena. The circadian rhythm should not be a significant complicating factor in studies of operantly conditioned H-reflex change.

Animals↗

PubMed1994

Operant conditioning of primate H-reflex: phases of development.

This study sought to determine whether operantly conditioned change in the primate triceps surae (TS) H-reflex develops in distinct phases. Data from 20 animals in which the TS H-reflex in one leg was trained up (i.e., HRup mode) and 18 in which it was trained down (i.e., HRdown mode) were averaged to define H-reflex behavior in trained and control legs. In HRup animals, the trained-leg H-reflex showed a large phase I increase in the first two days followed by gradual phase II increase that continued for weeks. The control-leg H-reflex appeared to show much smaller phase I and phase II increases. In HRdown animals, the trained-leg H-reflex decreased gradually over weeks, while the control-leg H-reflex appeared to increase within 2 days and did not change from then on. The initial rapid increase in the HRdown control leg suggested that two early events occurred in the HRdown trained leg: a nonspecific increase like that in the control leg and an operantly conditioned mode-specific decrease. These two effects may have obscured each other, so that H-reflex size in the HRdown trained leg did not drop rapidly in the first few days. These results improve understanding of adaptive H-reflex change as an operantly conditioned phenomenon, and provide encouragement and direction for efforts to reproduce and study the phenomenon in reduced or anesthetized preparations.

Animals↗

PubMed1996

Reversal of H-reflex operant conditioning in the rat.

In response to an operant conditioning task, rats can gradually increase or decrease soleus H-reflex amplitude without change in background electromyographic activity or M response amplitude. Both increase (under the HRup mode) and decrease (under the HRdown mode) develop over weeks. The present study investigated reversal of conditioned H-reflex change. Following collection of control data, rats were exposed to one mode (HRup or HRdown) for 50 days, and then exposed to the opposite mode for up to 72 days. Rats responded to each mode exposure with gradual, mode-appropriate change in H-reflex amplitude. This finding is consistent with other evidence that H-reflex conditioning depends on spinal cord plasticity. The effects of exposure to the HRup (or HRdown) mode were not affected by whether exposure followed previous exposure to the HRdown (or HRup) mode. In accord with recent studies suggesting that HRup and HRdown conditioning have different spinal mechanisms, these results suggest that reversal of H-reflex change is due primarily to the superimposition of additional plasticity rather than to decay of the plasticity responsible for the initial change.

Animals↗

PubMed1978

How operant conditioning can contribute to behavioral toxicology.

Operant conditioning can contribute to the development of behavioral toxicology in many ways. Its techniques are useful in training animals in the various behaviors the toxicologist may wish to study. They make possible the sophisticated assessment of sensory functioning. Operant conditioners excel at using schedules of intermittent reinforcement to create the type of stable animal performance needed in studying substances that produce effects only after prolonged exposure. Schedule-controlled behavior also helps elucidate the precise behavioral mechanisms involved in toxicity. In the early assessment of toxic substances a judiciously chosen sample of schelule-controlled performances may provide the best estimate whether the integrity of complex operant behavior remains unchanged. The development of improved behavioral techniques and computer technology promises to bring down the cost of such assessment.

Animals↗

PubMed2001

Time-dependent effects of pyramidotomy in the operantly conditioned rats.

The effect of unilateral transection of bulbar pyramid on operantly conditioning in rats, have been shown to be in direct relationship with the time of its execution. Stable instrumental reflexes reappeared on average 3.9 days after the transection of the bulbar pyramid. However, preliminary transection of the pyramid led to the prolongation of stabilization of operant conditioning after an average of 16.5 days. These findings are considered to be in view of the mechanisms of switching of descending influences of corticospinal and cortico--rubrospinal systems.

Animals↗

PubMed1967

Operant conditioning of schizophrenic children.

Though there is little agreement concerning the diagnosis, incidence or etiology of childhood schizophrenia, until recently most authors agree there is no effective treatment. Operant conditioning is reported to succeed where other therapies have failed. Twenty children diagnosed according to Creak's criteria in two groups matched for age, sex, duration of stay, Vineland score and amount of speech, were treated by either interpretive play therapy or operant conditioning. Emotional relatedness and self-identity, then imitation of behaviour and speech were conditioned with the positive reinforcements of candy. Tested before, during and after fifty 45-minute sessions, those in the operant-conditioning group had gained more speech and improved more on Vineland score. The relative efficacy of operant conditioning may be related to the greater ease with which the staff learned this technique and the need of these children for predictable routines. The experiment will continue with a crossover complex.

Awareness↗

PubMed1993

A cellular analogue of operant conditioning.

Using the hippocampal-slice preparation, we attempted to model operant conditioning in vitro by reinforcing pyramidal cell bursting responses with local micropressure applications of transmitters and drugs. The same injections were administered independently of bursting to provide a "noncontingent" control for direct pharmacological stimulation or facilitation of firing. The results suggested that the bursting responses of individual CA1 pyramidal neurons may be reinforced in a dose-related manner by response-contingent (but not noncontingent) injections of dopamine and the selective dopamine D2 agonist, N-0923. N-0924, a stereoisomer of N-0923 that is largely devoid of D2-agonist activity, failed to reinforce CA1 bursting. Burst-contingent injections of the excitatory neurotransmitter glutamate also failed to reinforce CA1 bursting; indeed, the glutamate applications (whether contingent or random) reduced the likelihood of bursts while increasing the frequency of solitary spikes. Reinforcement delays exceeding 200 ms largely eliminated the reinforcing efficacy of the D2 agonist N-0437 in CA1 operant conditioning. The results are consistent with the suggestion that the behaviorally reinforcing effects of dopaminergic agents can be modeled in vitro in the hippocampal-slice preparation.

Animals↗

PubMed1999

The dynamics of operant conditioning.

Existing models of operant learning are relatively insensitive to historical properties of behavior and applicable to only limited data sets. This article proposes a minimal set of principles based on short-term and long-term memory mechanisms that can explain the major static and dynamic properties of operant behavior in both single-choice and multiresponse situations. The critical features of the theory are as follows: (a) The key property of conditioning is assessment of the degree of association between responses and reinforcement and between stimuli and reinforcement; (b) the contingent reinforcement is represented by learning expectancy, which is the combined prediction of response-reinforcement and stimulus-reinforcement associations; (c) the operant response is controlled by the interplay between facilitatory and suppressive variables that integrate differences between expected (long-term) and experienced (short-term) events; and (d) very-long-term effects are encoded by a consolidated memory that is sensitive to the entire reinforcement history. The model predicts the major qualitative features of operant phenomena and then suggests an experimental test of theoretical predictions about the joint effects of reinforcement probability and amount of training on operant choice. We hypothesize that the set of elementary principles that we propose may help resolve the long-standing debate about the fundamental variables controlling operant conditioning.

Animals↗