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.     

Suggested Greek translations of expressions in the experimental analysis of behavior

Greek-English and English-Greek translations of expressions in the experimental analysis of behavior are presented. Included is a short discussion of some of the problems which arose, partly because of the mentalistic nature of Greek science.     

Connectionist models of conditioning: A tutorial

Models containing networks of neuron-like units have become increasingly prominent in the study of both cognitive psychology and artificial intelligence. This article describes the basic features of connectionist models and provides an illustrative application to compound-stimulus effects in respondent conditioning. Connectionist models designed specifically for operant conditioning are not yet widely available, but some current learning algorithms for machine learning indicate that such models are feasible. Conversely, designers for machine learning appear to have recognized the value of behavioral principles in producing adaptive behavior in their creations.     

Time horizons in rats: the effect of operant control of access to future food.

The primary goal of this experiment was to determine whether the addition of an operant requirement for access to a less costly (continuous reinforcement) patch of future food increased the time horizon over which that future patch decreased intake in a currently available depleting (progressive-ratio) patch. Three groups of 4 rats were tested. Each member of the earned-time group was required to cumulate a fixed-time outside the progressive-ratio patch to obtain access to food in the less costly patch; the fixed-time requirement ranged from 2 to 64 min. Rats in the matched-time group received response-independent access to less costly food at the average delay shown by the earned-time group. Rats in the matched-time no-food group were removed from the chamber at the same average delay without receiving access to less costly food. Two of the earned-time rats showed an increased time horizon relative to that shown by the matched-time rats (approaching 40 min for 1 rat). The other 2 earned-time rats markedly increased instrumental responding but showed suppression of intake only when food was less than 20 min away. The matched-time group showed less suppression of intake over a similar range of delay intervals. Surprisingly, the matched-time no-food animals also showed suppression of intake concentrated at the end of the session, possibly reflecting the receipt of their entire daily ration 30 min after the session. The potential importance of time horizons to the foraging process is clear, but experimenters are still working out paradigms for investigation of these horizons.     

A comparison of operant licking and lever pressing in the rat

Two groups of rats were trained on a signaled, free-operant, avoidance procedure to lick or to lever press in order to avoid shock while water-deprived or satiated and, in the case of licking, while ingesting deionized water, isotonic saline, or 10% sucrose. The most effective avoidance licking occurred while the rats were water-deprived and ingesting 10% sucrose. Water deprivation level had no effect on lever pressing for shock avoidance. Two other groups of rats were operantly conditioned to lick or to lever press for food pellets while waterdeprived or satiated and, in the case of licking, while ingesting deionized water or 10% sucrose. The most effective licking for food reinforcement occurred while the rats were water-deprived and ingesting 10% sucrose. Water deprivation level had no effect on lever pressing for food reinforcement. The data indicated that effective operant licking must be supported by factors related to water regulation and taste palatability.     

Benefits to the Spanish research community of regional content expansion in Web of Science

The regional content expansion of Thomson Reuters (formerly ISI) Web of Science added approximately 1,600 journals to the database with a regional as opposed to international focus. Web of Science coverage has grown to reflect the changing nature of global research publication trends and the additional regional journals provide greater visibility to high quality local studies beyond their traditional boundaries. The cited references indexed from the regional journals represent the influence of those journals on both the global and local research communities. This study analyses the impact of adding Spanish regional journals to Web of Science on the publication and citation patterns of Spanish research. The findings demonstrate a recent increase in research output from Spain and this is explained by more Spanish research being produced rather than due to the indexing of more Spanish journals; indeed it is shown that the majority of Spanish research is not published in Spanish journals. An analysis of Spanish journal citations uncovers a Spanish regional citation network previously undetected and serves as valuable information for evaluators of Spanish journals.     

In vitro reinforcement of hippocampal bursting: a search for Skinner's atoms of behavior.

A novel "in vitro reinforcement" paradigm was used to investigate Skinner's (1953) hypotheses (a) that operant behavior is made up of infinitesimal "response elements" or "behavioral atoms" and (b) that these very small units, and not whole responses, are the functional units of reinforcement. Our tests are based on the assumption that behavioral atoms may plausibly be represented at the neural level by individual cellular responses. As a first approach, we attempted to reinforce the bursting responses of hippocampal units in a highly reduced brain-slice preparation with local micropressure applications of behaviorally reinforcing dopaminergic drugs. The same injections were administered independently of bursting to provide a "noncontingent" control for nonspecific stimulation or facilitation of firing. It was found that the bursting responses of individual CA1 pyramidal neurons may be progressively facilitated in a dose-related manner by response-contingent (but not noncontingent) injections of dopamine itself, the dopamine D1-preferring agonist SKF 82958, the D3-preferring agonist quinpirole, and the D2-like selective agonist (+)-4-propyl-9 hydroxynapthoxazine. These findings support the conclusion that unit bursting responses can be reinforced in vitro in hippocampal slices, and they further suggest that the same dopamine receptor subtypes are involved in both cellular and behavioral operant conditioning. The results thus provide indirect support for Skinner's atoms-of-behavior hypothesis.     

Protection motivation and self-efficacy: A revised theory of fear appeals and attitude change

The effects of fear appeals on persuasion were investigated in a factorial experiment that was designed to test a combined model of protection motivation theory and self-efficacy theory. As predicted, the probability of a threat's occurrence and the effectiveness of a coping response both had positive main effects on intentions to adopt a recommended preventive health behavior. More importantly, the findings provided support for self-efficacy expectancy as a fourth component of protection motivation theory: Self-efficacy had a direct influence on intentions and interacted with two other variables of protection motivation theory. The interaction effect was interpreted in terms of two new decision-making strategies that people use when confronted with a fear appeal: a precaution strategy and a hyperdefensiveness strategy. In addition, the results replicated previous findings on the relationship between self-efficacy expectancy and outcome expectancy. A model incorporating protection motivation theory and self-efficacy theory is presented as a possible general model of attitude change.     

A transformation of respondently conditioned stimulus function in accordance with arbitrarily applicable relations.

Adult male subjects saw a sexual film clip paired with a nonsense syllable (C1). Similarly, an emotionally neutral film clip was paired with a second nonsense syllable (C3). Responses to the nonsense syllables were recorded as skin resistance responses. Subjects were also trained in a series of related conditional discriminations, using the C1 and C3 stimuli, from which the following equivalence relations were predicted; A1-B1-C1, A2-B2-C2, and A3-B3-C3. Some subjects were given matching-to-sample (equivalence) tests after the conditional discrimination training (Experiment 1), whereas others were not (Experiment 2). Subjects were tested for a transformation of eliciting functions by presenting the A1 and A3 stimuli, which were related through equivalence to C1 and C3, respectively. Five of the 6 subjects who showed significantly greater conditioned responses to C1 than to C3, also showed significantly greater skin resistance responses to A1 than to A3. Two additional subjects demonstrated a transformation of an eliciting stimulus function in accordance with five-member equivalence relations (Experiment 3), and another 5 subjects demonstrated similar effects in accordance with the relations of sameness and opposition (Experiment 4).