The influence of the initial reinforcement value on physiological parameters of conditioned respiratory reflex

BACKGROUND: Most of the studies of the role of reinforcement in the formation of adaptive behavior were performed on animals. At the same time, such an experimental model as a conditioned respiratory reflex to resistive load, has not been sufficiently studied, although an unconditioned reflex to additional resistance to breathing, on the basis of which a conditioned one is formed, is a stable reaction that has clear quantitative evaluation criteria, and the conditioned reflex itself is relatively strong, easily normalized, reluctantly extinguished and does not require observance of a number of methodological conditions. AIM: To study the influence of the initial value of reinforcement on the physiological parameters of the conditioned respiratory reflex. MATERIALS AND METHODS: The work was carried out on people of both genders, 16 people, aged 18 to 44, practically healthy. The unconditioned stimulus was applied in four gradations of external respiratory resistance: 11; 28; 54; 76 cm water • l/sec. The conditioned reflex was formed by the classic type, the duration of application of the conditioned stimulus was not fixed and its end coincided with the end of the action of the unconditioned stimulus, the period of the isolated action of the conditioned signal was 10 sec. As physiological parameters, we studied the ventilatory and motor parameters of respiration, the temporal parameters of the conditioned reaction. RESULTS: The influence of the unconditioned stimulus on the value of the tidal volume after the combination in all subjects depended on the absolute reinforcement values used in this combination, and was weakly connected with the initial reinforcement value. The influence of the external resistance on breathing used in this combination was significantly higher on such parameters as intraoral pressure of inspiration and expiration; the role of the initial reinforcement value in the dynamics of the given parameters was not confirmed. CONCLUSIONS: Most “sensitive” to the action of the initial value of the resistive load were the temporal parameters of the conditioned respiratory reflex — the latent period and the time of the conditioned reaction; the parameters of the “ventilatory” and “motor” outputs of the external respiration system changed noticeably, the spirometric parameters showed very little dynamics, and the capnographic parameters practically did not change. The dynamics of the parameters of the conditioned respiratory reflex to increased external respiratory resistance permits to single out groups of signs that have the greatest semantic significance for evaluation of the system-forming and discriminating role of the initial gradation of the reinforcement factor.

Pathophysiological mechanisms of resistive breathing

AIM: This study aimed to explore the pathophysiological mechanisms of resistive breathing by using a model of a conditioned respiratory reflex to external resistance to breathing. MATERIALS AND METHODS: Inspiratory resistive loads were used 11, 28, 54, and 78 cmAq/l/s to model a conditioned respiratory reflex. External respiration was parametrized on the basis of the analysis of motor and ventilatory outputs. Conditioned signals were pure sounds exceeding the threshold of perception by 10 db at 2000 Hz frequency. All the test persons were divided into two groups (large and small groups) according to the initial reinforcement value. (1) In the large group (37 individuals), the conditioned reflex was formed from 11 cmAq/l/s that was subsequently increased stepwise in the load to 76 cmAq/l/s. (2) In the small group (18 individuals), the initial reinforcements were different gradations of resistive loads, with a stepwise transition to the other parameters of an unconditioned stimulus. The period of the isolated application of a conditioned signal (CS) was 20 s, the interval between signals was not fixed, varying from 2 min to 4 min. Six to eight combinations of the conditioned and unconditioned stimuli were used for 1 day of the experiment. RESULTS: The increase in the added respiratory resistance was associated with the pronounced reduction of pulmonary and alveolar ventilation, that is, with the hypoventilation type of resistive load realization. Changes in ventilation during the isolated application of a conditioned signal had an alternative character. In particular, as the reinforcement factor increased, a pronounced shift to hyperventilation was noted. CONCLUSION: The reinforcement value of the conditioned reflex changed stepwise, thereby significantly restructuring the proportion between the effectiveness of the adaptive activity in the realization of external resistance to inspiration (the time of stay under a certain load) and its physiological cost (totalities of the deviations of physiological and energy parameters).

Devaluation of a conditioned reinforcer requires its reexposure

A change in motivational state does not guarantee a change in operant behaviour. Only after an organism has had contact with an outcome while in a relevant motivational state does behaviour change, a phenomenon called incentive learning. While ample evidence indicates that this is true for primary reinforcers, it has not been established for conditioned reinforcers. We performed an experiment with rats where lever-presses were reinforced by presentations of an audiovisual stimulus that had previously preceded food delivery; in the critical experimental groups, the audiovisual stimulus was then paired a single time with a strong electric shock. Some animals were reexposed to the audiovisual stimulus. Lever-presses yielding no outcomes were recorded in a subsequent test. Animals that had been reexposed to the audiovisual stimulus after the aversive training responded less than did those that had not received reexposure. Indeed, those animals that were not reexposed did not differ from a control group that received no aversive conditioning of the audiovisual stimulus. Moreover, these results were not mediated by a change in the food’s reinforcement value, but instead reflect a change in behaviour with respect to the conditioned reinforcer itself. These are the first data to indicate that the affective value of conditioned stimuli, like that of unconditioned ones, is established when the organism comes into contact with them.

The influence of cutouts in slabs of formwork-free molding on their load-bearing capacity

The paper presents the results of testing the slab of formwork-free molding (PB slab) for strength, as well as numerical study of the finite element model of this slab. It is shown that with an angular cutout in the PB slab, its load bearing capacity decreases and the nature of fracture changes. Partial compensation for the load-bearing capacity reduction of the slab with such a cutout can be achieved by reducing the pre-stressing reinforcement value of reinforcement rods cut off during the formation of the cutout, or by redistributing the reinforcement along the cross-section of the slab.

DEMAND FOR SOCIAL CONTACT IN RATS: TOWARD A QUANTITATIVE ANALYSIS OF SOCIAL REINFORCEMENT VALUE

Rats were studied in social-release procedures, in which lever presses by one rat released a second rat from a tube restraint for a period of social interaction. Both the fixed-ratio price and the duration of social contact were varied systematically on a within-subject basis, generating a total of 27 demand functions across six subjects. Overall, the data were well accounted for by the essential value model (96% VAF), supporting a social reinforcement view, according to which social-release behavior is maintained by social contact with another rat. Response rates and parameter fitswere comparable in 25-min and 120-min sessions, showing little evidence of satiation.Overall, the findings suggest that socially-reinforced behavior shares functionalproperties with other reinforcers, and illustrate a promising set of methods for quantifying social reinforcement value.

The Impact of E-liquid Propylene Glycol and Vegetable Glycerin Ratio on Ratings of Subjective Effects, Reinforcement Value, and Use in Current Smokers

Introduction Electronic nicotine delivery systems (ENDS) vary on a wide range of characteristics that may affect reinforcement value and use. One characteristic is the ratio of two solvents commonly used in most e-liquids: propylene glycol (PG) and vegetable glycerin (VG). The goal of this study was to understand how PG/VG ratio affects subjective effects, reinforcement value, and tobacco use patterns among current smokers who try using ENDS. Aims and Methods Current smokers with minimal ENDS use history (n = 30) sampled, in a double-blind fashion, three different e-liquids that varied in PG/VG ratio (70/30, 50/50, 0/100) while holding constant other aspects of the e-liquid and ENDS. Participants tried each e-liquid before rating the subjective effects on a modified version of the Cigarette Evaluation Questionnaire. Reinforcement value was assessed using a preference task where participants chose between the three e-liquids. The impact of each e-liquid on cigarette reinforcement was assessed using a modified version of the Cigarette Purchase Task. Participants were randomly assigned to receive one e-liquid to take home for 1 week. Results PG/VG ratio had minimal impact on most of the tested outcomes. Participants rated the highest PG concentration as having a stronger “throat hit” than the other two. There was no significant difference between the number of participants who preferred each of the PG/VG ratios in the preference assessment. PG/VG ratio did not affect cigarette or ENDS use during the sampling week. Conclusions These data suggest that PG/VG ratio has minimal impact on subjective effects and reinforcement value in ENDS naive current smokers. Implications These data suggest that PG/VG ratio, within the range that is commonly used, has minimal impact on subjective effects, reinforcement value, or uptake in current smokers with minimal ENDS experience.