PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Reinforcement learning”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2005

Local preference in concurrent schedules: the effects of reinforcer sequences.

We investigated the effects that sequences of reinforcers obtained from the same response key have on local preference in concurrent variable-interval schedules with pigeons as subjects. With an overall reinforcer rate of one every 27 s, on average, reinforcers were scheduled dependently, and the probability that a reinforcer would be arranged on the same alternative as the previous reinforcer was manipulated. Throughout the experiment, the overall reinforcer ratio was 1:1, but across conditions we varied the average lengths of same-key reinforcer sequences by varying this conditional probability from 0 to 1. Thus, in some conditions, reinforcer locations changed frequently, whereas in others there tended to be very long sequences of same-key reinforcers. Although there was a general tendency to stay at the just-reinforced alternative, this tendency was considerably decreased in conditions where same-key reinforcer sequences were short. Some effects of reinforcers are at least partly to be accounted for by their signaling subsequent reinforcer locations.

Animals↗
PubMed1986

Identification of the neural pathway for reinforcement of feeding when Aplysia learn that food is inedible.

Bilateral sectioning of the esophageal nerves that innervate the gut of Aplysia was found to have profound effect on response decrement to inedible food: Time to criterion for cessation of feeding was elevated, no memory of the decrement was present 24 hr after training, and motor patterning during training was altered. The parametric features of response decrement to sustained lip stimulation were examined to determine their resemblance to parameters of response decrement to inedible food after esophageal nerve sectioning. Parameters of response decrement were similar, indicating that after esophageal nerve sectioning response decrement is likely to be the result of sustained lip stimulation. Bilateral nerve sectioning had no effect on decrement due to sustained lip stimulation. Unilateral lesions and lesions of either of the two major divisions of the esophageal nerves had no effect on learning that food was inedible. The data indicate that bilateral nerve sectioning eliminates all stimuli causing negative reinforcement of feeding due to failure to consume food. Based on the data in this and the previous paper, a model is presented suggesting sites of action and mechanisms for learning that foods are edible or inedible in Aplysia.

Animals↗
PubMed2006

Initial-link duration and acquisition of preference in concurrent chains.

Initial-link response allocation in concurrent chains becomes less extreme as the absolute duration of the initial links increases (Fantino, 1969). The present study asked whether initial-link duration affected how quickly response allocation reached asymptote (i.e., acquisition of preference). Six pigeons were trained on a concurrent-chains procedure in which the terminal links were fixed-interval (FI) 8 sec FI 16 sec or FI 16 sec FI 8 sec and were reversed every 20 sessions. Across conditions, all possible combinations of transitions between variable-interval (VI) 8-sec (short) and VI 24-sec (long) initial-link schedules were studied. Overall, the rate of acquisition was faster when the durations of the initial links preceding the reversal were short rather than long, and when the durations of the initial links following the reversal were long rather than short. By contrast, initial-link duration had no effect on acquisition or asymptotic measures of temporal control of terminal-link responding. These results support the core principle of delay-reduction theory (Fantino, 1969) that the impact of a conditioned reinforcer varies directly with initial-link duration, but also suggest that temporal learning during the terminal links proceeds independently ofinitial-link duration.

Animals↗
PubMedDate not supplied

[Activity of neurons in the pedunculopontine nucleus in conditioned instrumental appetitive reflex].

Activity of 91 neurons in the compact and diffuse parts of the pedunculopontine tegmental nucleus (PPTg) was recorded in freely moving rabbits during execution of instrumental appetitive conditioning. Of the recorded neurons, 37.4% changed their activity in response to a conditioned stimulus, which is the evidence for the PPTg involvement in instrumental conditioning. Excitatory conditioned neuronal responses to the conditioned stimulus and food reinforcement significantly prevailed over inhibitory reactions. Neuronal responses to the conditioned stimulus were classified in several basic patterns reflecting stimulus effects, structure of the behavioral act, and reinforcement properties. These reactions indicate the involvement of the PPTg in attention, motor learning, and reinforcement. The revealed differences in associative reactive properties of the compact and diffuse parts of the PPTg to the conditioned stimulus and reinforcement point to the functional heterogeneity of this structure and suggest the leading role of the cholinergic part of the PPTg in instrumental appetitive conditioning and reinforcement as well as the essential contribution of the diffuse part into classical appetitive conditioning.

Animals↗
PubMed1999

Effects of excitotoxic lesions of the basolateral amygdala on conditional discrimination learning with primary and conditioned reinforcement.

Rats with excitotoxic lesions of the basolateral amygdala (BLA) were not impaired in the acquisition of an appetitive visuospatial conditional discrimination between stimuli varying in temporal frequency that has previously been shown to be sensitive to the effects of lesions of the striatum and cingulate cortex. After asymptotic performance was attained, discrimination was reinforced according to a fixed ratio (FR) schedule under which n presentations of sucrose were provided following n correct responses; each correct response also being reinforced immediately by a light acting as a conditioned reinforcer. Under these conditions of reinforcement when FRn=5, BLA-lesioned rats initially showed transient impairments in several aspects of performance, but rapidly attained control levels over subsequent test sessions. No further impairments occurred when FRn=10/20. However, in various conditions of extinction, further differences in performance were revealed between the BLA-lesioned and control groups, notably a significantly enhanced resistance to extinction when both sucrose and conditioned reinforcement were omitted. The results are discussed in terms of limbic-striatal mechanisms in the control of discrimination learning and the possible role of the amygdala in the mediation of different aspects of conditioned reinforcement.

Amygdala↗
PubMed1962

The conditioning of textual responses using "extrinsic" reinforcers.

Six 4-year-old Ss were presented with a textual program consisting of 26 words arranged so the word stimuli were gradually combined into sentences and then short "stories." Three Ss were given the No-Reinforcement condition first, and only social reinforcers were presented. They were switched to the Reinforcement condition as soon as they requested discontinuance of the activity. The other three Ss were given Reinforcement-No Reinforcement-Reinforcement treatments. The No-Reinforcement treatment in this case lasted until S requested discontinuance of the activity. The reinforcers were mixed edibles and trinkets, as well as tokens backed up by small plastic toys on a 1:24 ratio. The unit of response was the number of new texts acquired as a result of each of the 45-min experimental sessions. It was demonstrated that the program, procedure, and reinforcement conditions produced curves which are analogous to those produced in common operant-conditioning procedures. The results indicate that other operant principles may be studied in this significant area of human behavior, with important practical consequences.

Conditioning, Operant↗
PubMed1981

An attempt to use central dopaminergic stimulation as a reinforcement for T-maze learning in rats.

Two groups of 8 rats with unilateral cannulas aimed at the lateral hypothalamus (LH) or nucleus accumbens (nAcc) were trained in a T-maze to receive intracerebral injections of dopamine as a reinforcement for choosing the proper arm of the maze. Neither in the LH nor in the nAcc groups did dopamine show evident reinforcing properties comparable to those found earlier for noradrenaline.

Animals↗
PubMed1979

Interdisciplinary inpatient warfarin education program.

An educational program on warafarin counseling for inpatients of a 200--bed community hospital which uses both pharmacy and nursing personnel is described. Following a physician's request for the educational service, a registered nurse arranged for the patient to view a slide presentation of anticoagultants and provided a booklet designed to reinforce the learning objectives for the warfarin education program. After the patient viewed the film and read the booklet, a pharmacist or nurse made a follow-up visit to answer questions and reinforce the objectives. The checklist of learning objectives was completed by the pharmacist or nurse and remained in the patient's chart as a permanent record of medication counseling. Forty-five request for warfarin patient education were received during the program's first six months of operation. The pharmacist spent an average of 30 minutes with each patient; the nurse spent an average of 15 to 20 minutes with each patient. The average time required of nursing and pharmacy service to provide the program was one and two hours per week, respectively. The warfarin education program provides an important patient service with a reasonable expenditure of time by pharmacy and nursing personnel.

Hospitals, Community↗
PubMed1962

FI length and performance of an FI FR chain schedule of reinforcement.

In a chained FI FR schedule, manipulating the length of the FI component produced changes confined almost entirely to the FI performance; increasing the interval length increased the total number of responses emitted per reinforcement. The configuration of the fixed-interval scallop was clearly modified as the interval length was increased, with the larger intervals becoming flatter (i.e., a larger proportion of the total responses earlier in an interval). Measurement of the postreinforcement pause is suggested as a possible indicator of fixed-interval scalloping.

Learning↗
PubMed1965

DISCRIMINATIVE FUNCTIONS BASED ON A DELAY IN THE REINFORCEMENT RELATION.

Pigeons were shown to come under discrimination control when the S(D) and S(Delta) were temporally separated from reinforcement and non-reinforcement. S(D) and S(Delta) consisted of distinctive key illuminations presented separately. Responding on an FR 5 in the presence of S(D) or S(Delta) produced a third stimulus containing a schedule requirement. If this third (or interpolated) stimulus was preceded by S(D), responding in its presence produced reinforcement followed by a time-out (TO). If, on the other hand, the third stimulus was preceded by S(Delta), responding produced TO alone. In this fashion, the same stimulus and the same response requirement were imposed between S(D) and the reinforcement as between S(Delta) and the TO. In Experiment I, the schedule employed during the interpolated stimulus was FR; in Experiment II, FI. Discrimination reversal was accomplished in both experiments.

Animals↗