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Results for “Conditioning, Operant”

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PubMed1996

Activity of neurons of the subthalamic nucleus in relation to motor performance in the cat.

The activity of subthalamic nucleus neurons related to motor performance was studied in three unrestrained cats operantly conditioned to perform a lever-release movement. The movement was initiated either rapidly after the trigger stimulus (a brief sound) in a simple reaction-time paradigm or after a delay in trials identified by a tone cue. These paradigms were randomly presented. The activity of 171 neurons was recorded in the contralateral and in the ipsilateral subthalamic nucleus, with respect to the performing limb. The mean spontaneous activity of cells in the ipsilateral side (18.5 +/- 13.8 imp/s, mean +/- SD) was higher than that in the contralateral side (8.5 +/- 8.1 imp/s). A total of 145 cells (85%) presented significant changes in activity in relation to the lever-release movement (task-related cells). The remaining 26 cells were either related to other events of the task (n = 15; lever-press or reinforcement occurrence) or not related at all to the task performance (n = 11). The majority of changes of activity of task-related cells were initial increases in discharge, which started on average, 127 ms before movement onset and lasted several hundreds of milliseconds. These increases in discharge were more frequent in the contralateral side (75 of 80 task-related cells, 94%) than in the ipsilateral side (43 of 65 task-related cells, 66%). The changes in activity, either increases or decreases, occurred early after the trigger stimulus, since 62% of them had a latency of less than 100 ms. Although the mean latency of initial increases was rather similar in both sides (97 ms contralateral versus 104 ms ipsilateral), the contralateral side was characterized by a high proportion of very early responses (less than 20 ms). For most neurons, the early changes in activity described above were absent after the trigger stimulus in the delayed condition. For certain neurons, the changes in activity prior to movement were different in reaction-time condition and in delayed condition, showing that the pattern of activity preceding movement might depend on the temporal requirements for motor initiation. The results suggest that a significant proportion of subthalamic cells are involved in the preparation and the initiation phases of the lever-release movement studied, although other hypotheses (e.g. stimulus-related responses) cannot be definitely ruled out. The timings and patterns of the changes in activity observed in the subthalamic nucleus in the present study, and in the pallidal complex previously, cannot be explained easily by the classical scheme where the external pallidum inhibits the subthalamic nucleus. The results suggest rather that the subthalamic nucleus, driven by a yet-to-be-determined excitatory input, exerts an excitatory influence on the pallidum and plays a crucial role in the control of the basal ganglia output neurons.

Acoustic Stimulation↗

PubMed1994

Characteristics of posture alterations associated with a stepping movement in cats.

The relationship between changes in posture and the performance of a forelimb movement required for a transition between two stance positions was analysed in cats. The task consisted of an operantly conditioned, forelimb stepping movement from one support platform to another located more anterior. The reward was given only after a specific vertical force was applied to the second platform. This ensured that the cat performed a clear transition from its initial stance posture to another requiring a different weight distribution. The strategy adopted by an animal during the conditioned movement was studied by analysing the distribution of the vertical forces as a function of time. Specific quantitative functions were used to describe the weight distribution in the anterior-posterior, right-left and diagonal directions as the task was performed. The temporal parameters characterising this behaviour were not significantly different between animals, except for reaction times. In contrast, spatial parameters reflected in the distribution of vertical forces generated during the performance of the task were characteristic for each animal. As a consequence, a variety of strategies were employed. Nevertheless some general features were found, including the persistence of a diagonal support pattern during the phasic part of the movement, and an initial movement to the side of the forepaw performing the movement. The findings support the view that each animal exhibits a specific strategy for performing this well-learned task, and that the strategy is consistently employed over consecutive trials of the movement.

Animals↗

PubMed1986

Impairment of stereoacuity in cats with oculomotor proprioceptive deafferentation.

Stereoacuity was measured with an operant conditioning technique in adult cats with unilateral deafferentation of oculomotor proprioception (section of the ophthalmic branch of the fifth cranial nerve). Binocular stereoacuity was found not to exceed monocular depth sensitivity, in contrast to what is obtained in normal cats. The results confirm previous findings and indicate a role of oculomotor proprioception in binocular depth perception of the cat.

Animals↗

PubMed1986

Premotor cortex of the rhesus monkey: neuronal activity in anticipation of predictable environmental events.

The activity of premotor cortex neurons was studied in macaque monkeys that were operantly conditioned to perform a visually guided motor task. The monkeys were given a visuospatial instruction stimulus (IS) that provided the target for a limb movement, but the monkey was not allowed to execute the movement until the later presentation of a trigger stimulus (TS). The IS was sometimes removed or the target changed during the interval between the IS and TS. Certain neurons became active before the IS, appearing to anticipate its location or time of occurrence, some of these and other neurons increased or decreased their discharge prior to a possible change in the IS, and other cells showed neuronal modulation that preceded the TS. The properties of some of these neurons were examined when the timing of the behavior-guiding visual signals or their probability of occurrence was made less predictable. In general, the neuronal activity described here was strongly influenced by changes in event predictability. These findings suggest that neuronal activity within the premotor cortex reflects the anticipation of predictable environmental events.

Animals↗

PubMed1981

Experimental methods in behavioral teratology.

The possibility that the exposure of the embryo to certain chemical substances can lead to behavioral disturbances is known from human epidemiological studies, e.g., in chronic poisoning with mercury and ethanol. Therefore, efforts are made to develop toxicological techniques with which new behavioral teratogens can be recognized. The review describes the most important experimental methods which are presently explored, and which are based on a rich body of knowledge accumulated by experimental psychologists. Most of the tests were developed with small animals, mostly with rats. They range from a rather straightforward determination of various reflexes to complex behavioral situations involving mechanical devices, operant conditioning techniques and procedures evaluating social behavior. In applying these methods in routine toxicology, it is important to remember, that many behavioral effects determined in newborn and adult animals are subtle. Moreover, they are influenced by a large variety of environmental factors affecting the health and the behavior of the mothers and of the offspring in the early and later phases of development. Therefore, the experiments must be conducted under highly standardized conditions and must be controlled rigorously. It is concluded that the best experimental strategy for the evaluation of potential behavioral teratogens is not yet established. Therefore, it would be premature to decide on a fixed protocol to be included in routine animal safety experiments for drugs and other chemical substances.

Animals↗

PubMed1975

[Study of efficacy of training emotional behaviour in groups (author's transl)].

A program of training emotional behaviour in groups and a method to prove its efficacy is reported. The objective of this treatment program is to improve recognition of emotional cues and adequate expression of emotions. The methods of behaviour therapy used in this program are: training of adequate behaviour be role-playing, modeling and operant conditioning. The study of efficacy is done as a group comparison between these therapy groups and the assertive training groups. Data are collected using self-rating scales, rating scales filled off by partners or relatives of the patients and direct behaviour ratings. Preliminary results show an improvement of selfrating data for the experimental and the control group, but there is no specific effect of one of the therapy programs.

Behavior Therapy↗

PubMed1976

Dffects of imipramine on auditory sensitivity in the rat in relation to initial sensitivity.

Rats were divided into 2 groups according to their absolute auditory thresholds, as measured by a psychophysical method of limits using an operant conditioning technique. The procedure required a water-deprived rat to bar press repeatedly until a 3 s pure tone (3 kHz) came on. VR-15 schedule was used to determined the frequency of occurrence of the tone. Only within 4 s after the tone onset could the rat get water reinforcement by sticking its nose into the dipper area. The descending method was used with tone intensities ranging from 120 to 40 dB, in 2 dB steps. Imipramine was then administered 3 times at 24-h intervals (40, 80 and 160 mg/kg, p.o., respectively), and each rat was tested at 4, 8, and 12 h after each administration. Rats with high initial thresholds showed a decrease in thresholds with the lower dose of imipramine, and those with low initial thresholds an increase with the higher dose. An analysis of variance of these data showed significant effects of the type of subject (in terms of the level of initial thresholds), dose and interval conditions, and their interaction. It was demonstrated that the lower the initial sensitivity the greater the increase in sensitivity by imipramine.

Animals↗

PubMed1978

Ethanol-reinforced behavior of rats with concurrent access to food and water.

Dippers filled with water or an ethanol solution were presented to male Wistar rats contingent on lever-pressing under a concurrent fixed-ratio 1 (water) fixed-ratio 1 (ethanol) schedule. During Phase I, when maintenance feedings were given during instead of following the daily 3-h sessions, the feedings increased drinking of both 8% (w/v) ethanol and water, with 8% ethanol being consumed in greater volumes than water. In Phase II, a 28-day transitional period from the food-deprived to the food-satiated state, continuous access to food during 3-h sessions moderately decreased 8% ethanol intake, and increased water intake and total liquid intake (water plus 8% ethanol). In Phase III, concurrent water and ethanol intake of food-satiated rats was compared over two identical series of ethanol concentrations (8, 11.3, 16, 22.6, 32, and 8% retest). Food was freely available in both the operant conditioning chambers and home cages. The number of dipper presentations of ethanol exceeded presentations of water for each rat at each concentration studied. Presentations of water were low in number and did not vary with the ethanol concentration. As the ethanol concentration was increased, the number of ethanol presentations decreased, while the quantity consumed (mg/100 g body weight/h) generally increased.

Animals↗

PubMed1975

Ethanol as a reinforcer for rats: effects of concurrent access to water and alternate positions of water and ethanol.

Water and ethanol solutions were concurrently made available on a continuous reinforcement schedule to 4 food-deprived male albino rats during daily 1-hr sessions in an operant conditioning chamber equipped with 2 levers and 2 liquid dippers. The number of ethanol reinforcements substantially exceeded the number of water reinforcements for each rat at each concentration studied (8, 16, and 32% w/v). Water reinforcements were low in number and did not vary with ethanol concentration. As the ethanol concentration was increased, the number of ethanol reinforcements obtained decreased, while the quantity consumed (mg/100 g of body weight/hr) increased. The highest rate of responding occurred at the beginning of the session.

Alcohol Drinking↗

PubMed1989

Nicotine and some related compounds: effects on schedule-controlled behaviour and discriminative properties in rats.

Behavioural effects of d- and l-nicotine, d- and l-nornicotine and l-cotinine were studied in two paradigms. In experiment 1, rats responded under a multiple fixed-interval (FI) 5 min, fixed-ratio (FR) 20 schedule of food presentation. Aside from differences in potency and time course, l-nicotine and the stereoisomers of nornicotine produced qualitatively similar effects on rates of responding. With increasing doses of drugs, FI response rates first increased and then decreased, while FR response rates only decreased. In contrast, d-nicotine did not significantly increase FI response rates at lower doses, and only decreased FI and FR response rates at higher doses. At doses up to 100 mg/kg, cotinine produced only dose-dependent increases in FI response rates and had no effect on FR response rates. Rate-increasing effects of cotinine were not blocked by mecamylamine. In experiment 2, rats were trained to discriminate between l-nicotine (0.1 mg/kg SC) and saline (0.1 ml/kg SC) in a two-bar, operant conditioning procedure under a tandem variable-interval (VI) 1 min, FR 10 schedule of food presentation. Full generalization was obtained to d-nicotine and to l- and d-nornicotine. Generalization to cotinine occurred only with large doses that contained significant amounts of nicotine present as an impurity. There was no generalization to non-nicotinic drugs (morphine and clenbuterol), even at doses that reduced response rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1981

The role of biofeedback in the operant modification of human heart rate.

The recent literature on the role played by biofeedback in the modification of human heart rate is reviewed. Emphasis is placed on research pertinent to the issue of whether biofeedback is more productively conceived as a reinforcer of an operant response or as a source of information enabling the development of a voluntary motor skill. Criticisms of the operant paradigm are answered, and limitations of the motor skills analogy are discussed. It is concluded that the operant conditioning paradigm best accounts for most available data on the role of biofeedback in heart rate control, and that it is superior to the motor skills model because it is more parsimonious and makes fewer untestable assumptions.

Biofeedback, Psychology↗

PubMed1979

An experimental investigation of the modifiability of the temporal structure of spontaneous speech.

This study attempted to test the hypothesis that the temporal structure of spontaneous speech is modifiable by reinforcing and punishing pauses, of a certain duration, in an operant conditioning situation. Pause rate was significantly affected by these contingencies: moreover, rate of change was rapid, indicating a "prepared" association between pausing and such contingencies. This study also attempted to test the hypothesis that there is a class of noncognitive pauses in monologue by punishing UPs to determine if UPs can be eliminated without affecting speech content. Although this manipulation did lead to a decline in pause rate, a significant increase in the amount of filled hesitation, particularly in repetition, resulted. This suggests that the overall amount of hesitation is fixed by the cognitive demands of the task but that a speaker is able to adapt to different interactional contexts by varying the category of hesitation used for cognitive planning.

Conditioning, Operant↗

PubMed1979

Electrocochleography and experimentally induced loudness recruitment.

The relationship between changes in loudness and the cochlear whole-nerve potential following experimentally produced deafness was studied in an animal model. Reaction time of a subject's response to an auditory stimulus has been shown to be an index of loudness in human experiments and has been adapted to nonhuman primates. In a series of experiments, four macaque monkeys were operantly conditioned to respond to 8-kHz tones over a range of 3--80 dB SPL, and their reaction times to pure tone stimuli were measured. Whole-nerve cochlear action potentials were recorded from chronic inner-ear electrodes. The relationship between behavioral and electrical measures of loudness recruitment were examined in animals with both temporary and permanent noise-induced hearing loss. Loudness recruitment was demonstrated experimentally after a 1-h exposure to a high-intensity 8-kHz octave band of noise. Excellent agreement was observed between the reaction time function and the action potential input-output function at intervals of 0.5, 12, 24, 48, and 84 h after exposure. Permanent hearing loss was produced in some of these animals by a much longer duration of exposure to the 8-kHz octave band of noise. Recruitment was observed in both the behavioral and the electrical measures. Histological studies of these damaged cochleas revealed primarily outer hair cell destruction, with a relative sparing of inner hair cells and nerve supply. The findings of this study are interpreted as strong support for the clinical electrocochleogram as an objective indicator of the presence of loudness recruitment.

Action Potentials↗

PubMed1975

Behavior modification as a therapeutic technique for use with parents of emotionally disturbed children in residential treatment.

This paper is based on the experience of the author in establishing and directing a program of behavior modification for children and their parents at the New Hampshire Hospital. The focus is on the operant conditioning procedures used with the parents to foster improved relationships with their children and between spouses. Attention was given to the promotion of awareness and praise for productive behaviors and extinction of hostility. Modeling, prompting, shaping, ignoring, and reinforcement principles were followed in parent activities such as TV viewing, individual and group counseling, and controlled visits with children.

Affective Symptoms↗

PubMed1978

Methylmercury chloride induces learning deficits in prenatally treated rats.

Methylmercury chloride (MMC) was given to pregnant rats on the 6th, 7th, 8th, and 9th day after conception in doses of 0.05 and 2.0 mg/kg/day. The female offspring of these animals were tested 90 days after birth for learning ability using operant conditioning procedures. The rats were kept at 90% of their normal body weight and trained in a lever-box to press a bar in order to obtain a food pellet. Significant differences in the acquisition speed became apparent when the ratio of bar presses to reward was increased in a classical contingency of differential reinforcement of high rates even at MMC-doses of 4 X 0.05 mg/kg. These differences were not found in the general motility level nor in motor coordination.

Animals↗

PubMed1993

Effect of lesions of the ascending 5-hydroxytryptaminergic pathways on choice between delayed reinforcers.

The possible involvement of the ascending 5-hydroxytryptaminergic (5HTergic) pathways in determining the effectiveness of delayed positive reinforcers was investigated using Mazur's (1984) adjusting-delay paradigm. Fourteen rats received injections of 5,7-dihydroxytryptamine into the dorsal and median raphe nuclei; 12 rats received sham lesions. The rats made repeated choices in a two-lever operant conditioning chamber between a smaller reinforcer delivered after a 2-s delay and a larger reinforcer delivered after a variable delay, the length of which was determined by the subject's previous choices. When the two reinforcers consisted of one and two food pellets, the "indifference point" (the delay to the larger reinforcer that rendered the two reinforcers equally effective) was shorter in the lesioned group than in the control group. Increasing the sizes of the reinforcers to three and six pellets reduced the indifference point in both groups and abolished the between-group difference. The levels of 5HT and 5-hydroxyindoleacetic acid (5HIAA) in the parietal cortex, hippocampus, amygdala, nucleus accumbens and hypothalamus were greatly reduced in the lesioned group, but the levels of noradrenaline and dopamine were not significantly affected. The results are consistent with the suggestion that the 5HTergic pathways play a role in maintaining the effectiveness of delayed reinforcers.

5,7-Dihydroxytryptamine↗

PubMedDate not supplied

Interneuron relationships in the basolateral amygdala in cats treated to select food on the basis of quality.

Cats were initially trained to make operant conditioned food responses to light by an "active selection of reinforcement" method. Provision of low-quality (a mixture of meat and bread) or high-quality (meat) reinforcement depended on the animal pressing a pedal in response to switching on a light with a short (1 sec) or long (10 sec) delay. Some animals responded to long delays--group I, animals with "self control," while others responded with short delays--group II, "impulsive" animals. Implanted semimicroelectrodes were used in chronic experiments to record multineuron activity in the basolateral amygdala. Cross-correlation analysis was used to study interneuron interactions in the spike discharges of individual neurons, extracted from multineuron activity. The numbers of interneuron interactions were significantly higher in "impulsive" cats of group II in all behavioral situations than in animals with "self control," and were dominated in "impulsive" animals by the shortest connections, with latencies of 0-30 msec. The largest numbers of connections in both groups were seen on omission of the conditioned pedal-pressing movement response, i.e., when the reinforcement selection task was more difficult. These data indicate that the basolateral amygdala should be regarded as a structure determining the individual typological characteristics of the animals' behavior.

Amygdala↗

PubMed2004

[Neuroendocrine changes and maladaptations in fibromyalgia. Etiopathogenetic findings].

This contribution presents the psychosocial, psychopathological, psycho- and elektrophysiological as well as endocrine results in the aetiopathogenesis of fibromyalgia syndrome (FMS). Three subgroups could be differentiated based on psychosocial learning processes. They differ in pain intensity and interference, affective distress, activity and spouse responses. They influence pain behavior and CNS activity in the sense of operant conditioning. The relationship between dysregulated pain modulation in the CNS and endocrine dysregulation of the HPA-axis, which seems to be relevant for the autonome hyporeaction of muscle and blood pressure, are discussed. The "dynamic processing model for FMS" is presented.

Adaptation, Physiological↗