Learning theory and the treatment of depression.
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Adjustment Disorders↗
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.
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Cognition in animals: learning as program assembly.
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Animals↗
Social drive or arousal: a test of two theories of social isolation.
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Analysis of Variance↗
The effect of clinical experience on dental students' ability to design removable partial denture frameworks.
To determine whether clinical experience influenced dental students' ability to correctly design removable partial denture frameworks, four combinations of six casts depicting various partially edentulous situations were used in the study. The authors independently rated the casts as to the degree of difficulty on a three-point scale. Only those casts for which there were 100% agreement were used. All of the casts that were used had a moderate degree of difficulty rating (level 2). The dental student sample consisted of 34 second-year students who had just completed 98 hours of instruction in removable partial dentures. Each student was given six casts on which to design removable partial denture frameworks. The students were evaluated before clinical experience in removable prosthodontics and after 1 year of removable prosthodontic experience. The results indicated that the dental students made significantly fewer errors in framework design after clinical experience. Errors on two of 13 framework design items were increased postclinically. The increase in errors on these two items may have been the result of a lack of attention to detail or a lack of reinforcement in learning certain basic concepts.
Clinical Clerkship↗
Operant conditioning studies of taste discrimination in the pigeon (Columba livia).
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Animals↗
Self-administration of neurokinin substance P into the ventromedial caudate-putamen in rats.
There is evidence that the neurokinin substance P plays a role in learning and reinforcement processes. Reinforcing effects of substance P were found upon injection into several parts of the brain. The aim of the present study was to gauge possible reinforcing effects of microinjections of substance P into the ventromedial caudate-putamen in rats. Two different behavioral paradigms were employed. In the first experiment a two-compartment choice procedure was used and the rats could trigger substance P injections (500 pg per 5 nl injection volume) into the ventromedial caudate-putamen by entering one distinctive compartment. During the injection period, substance P-injected animals spent significantly more time in the drug-paired compartment than vehicle-injected controls. In the second experiment, nose-poking through a hole in one wall of the cage was used as the operant. Rats that could self-administer substance P (100 pg per 5 nl injection volume) into the ventromedial caudate-putamen emitted a significantly higher rate of operant responding on the first day of testing and a significantly lower rate on the third day compared to vehicle-injected animals. The experiments provide evidence that the administration of substance P into the ventromedial part of the caudate-putamen can have positive reinforcing effects, but that repeated injections can have aversive properties. These effects are discussed, firstly, with regard to the possible mechanisms of intrastriatal substance P on striatonigral and striatopallidal output systems and, secondly, with respect to their possible relevance in the study of the basal forebrain reinforcement system.
Animals↗
Ethanol as a neurochemical surrogate of conventional reinforcers: the dopamine-opioid link.
Various lines of evidence support the view that ethanol is a neurochemical surrogate of conventional reinforcers, such as food and sex. In fact, ethanol activates central neuronal systems that utilize dopamine, opioids, and gamma-aminobutyric acid (GABA) as neurotransmitters and also are activated by conventional reinforcers. These neurotransmitter systems are likely to mediate specific aspects of ethanol's reinforcing properties. Activation of the mesolimbic dopamine and endogenous opioid systems might be the substrate of the incentive and rewarding (ergotropic) properties of ethanol (arousal, euphoria, motor stimulation) and of the process of acquiring ethanol-related secondary reinforcers (incentive learning) and ethanol self-administration habits. Stimulation of the endogenous GABAergic system might mediate the sedative and drive-reducing (trophotropic) properties of ethanol. The dopamine and opioid systems are largely interconnected. Thus, pharmacological blockade of the endogenous opioid system by mu- or delta-opioid receptor antagonists prevents ethanol's activation of the dopamine system and reduces ethanol consumption. This interaction might contribute to naltrexone's effectiveness in reducing alcohol craving in humans.
Animals↗
Acquisition versus steady state in the time-left experiment.
To test some predictions of scalar expectancy theory (SET) for the time-left procedure, we performed one experiment with two conditions. In Condition A, pigeons were exposed to two fixed-interval schedules, a fixed-interval (FI) 30s and an FI 60s, each associated with a distinct key and presented on a separate trial. Subsequently, during test trials, the FI 60-s key was illuminated and then after T = 15, 30 or 45 s the FI 30-s key also was illuminated. The main issue was how choice between the two keys varied with T. Condition B replicated Condition A with different FI parameters and T values. The results showed that (a) contrary to SET's predictions, preference changed reliably with testing, which suggests that learning took place during the test trials; (b) within each test trial, pigeons revealed an almost exclusive preference for one of the keys, and (c) at steady state pigeons behaved in the same way as rats. Because SET could not account for these findings we advanced a new descriptive model of performance for the time-left task. The model fit the data well.
Animals↗
Integrative dual-track transcriptomics reveals stage-specific coordination, regulatory divergence, and HSP90AA1-associated remodeling in human folliculogenesis.
Human folliculogenesis depends on coordinated yet non-identical developmental remodeling in the oocyte and its surrounding granulosa cells. When these two compartments remain synchronized and when they diverge into lineage-specific regulatory states, however, remains incompletely resolved. Here we performed an integrative dual-track re-analysis of the human RNA-seq dataset GSE107746, modeling oocytes and granulosa cells as distinct but developmentally linked compartments across follicular progression. Analysis of 148 sequencing libraries showed that compartment identity was the dominant source of transcriptomic variation, supporting compartment-aware downstream interpretation. Within this framework, oocytes followed a relatively continuous developmental trajectory, with substantial transcriptional remodeling already evident across adjacent stages, whereas granulosa cells showed weaker early-stage contrasts but markedly stronger late-stage reorganization, particularly around the antral and preovulatory transitions. Functional enrichment indicated that oocyte maturation was associated with RNA-processing and broader genome-regulatory remodeling, whereas granulosa maturation was dominated by progressive mitochondrial and bioenergetic activation. Co-expression analysis showed that both compartments contained strong late-stage programmes together with inverse early-state modules, indicating a shared systems-level architecture of maturation, although the hub-gene composition and biological content of these programmes were largely compartment-specific. Machine-learning validation reinforced this asymmetry: oocyte stage classification was best recovered from a compact eigengene-based representation, whereas granulosa stage discrimination was better resolved by a broader differential-expression-derived feature set. At the gene level, HSP90AA1 emerged as a stage-associated marker with compartment-specific behavior, showing progressive attenuation across oocyte development, assignment to the selected oocyte blue module, and sharper transitional dynamics in granulosa cells. Together, these findings support a model in which human folliculogenesis proceeds through coordinated but non-equivalent transcriptomic remodeling, with shared developmental logic at the systems level but distinct molecular execution in germline and somatic compartments.
Co-expression networks↗
NMDA antagonist AP-5 increase environmentally induced cocaine-conditioned locomotion within the nucleus accumbens.
An environment previously associated with cocaine use can elicit cravings, even in the absence of the drug, which may be due to the formation of strong associations between the environment and the drug. These associations can result from motor learning and reinforcing effects of cocaine, and may be mediated in part by ionotropic glutamate receptors in the nucleus accumbens (N.Acc.). To determine whether NMDA receptor activity in the N.Acc. affects the expression of conditioned locomotion, rats were trained using an environment-elicited cocaine-conditioning paradigm. Rats trained to pair a cocaine injection with an environment showed an increased locomotor activity when tested in the drug-paired environment, whereas rats injected with cocaine in their home cages did not exhibit greater locomotion. Significantly greater locomotor activity occurred in trained animals that received an infusion of AP-5, a NMDA receptor antagonist, into the N.Acc. These results suggest that animals trained to associate environmental cues with cocaine become conditioned to this environment. Furthermore, our finding demonstrates that NMDA receptor activation within the N.Acc. modulates cocaine-induced conditioning.
2-Amino-5-phosphonovalerate↗
The complex business of survival by aposematism.
The theory of warning signals dates back to Wallace but is still confusing, controversial and complex. Because predator avoidance of warningly coloured prey (aposematism) is based upon learning and reinforcement, it is difficult to understand how initially rare conspicuous forms subsequently become common. Here, we discuss several possible resolutions to this apparent paradox. Many of these ideas have been largely ignored as a result of implicit assumptions about predator behaviour and assumed lack of variation in the predators, prey and the predation process. Considering the spatial and temporal variation in and mechanisms of behaviour of both predators and prey will make it easier to understand the process and evolution of aposematism.
Journal Article↗
Effect of decaborane injection on operant behavior of monkeys.
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Animals↗
Nicotinic receptor function: new perspectives from knockout mice.
Knockout mice, in which one or more genes of interest are silenced, provide unique opportunities to analyse diverse aspects of gene function in vivo. In particular, the contribution of the encoded protein(s) in complex behaviours can be assessed. Since the first targeted disruption in 1995 of the gene encoding the beta2-subunit of the nicotinic acetylcholine receptor (nAChR), all but a few of the mammalian nAChR subunits have been disrupted (i.e. alpha7, alpha4, alpha3, alpha9, beta4 and beta3). Recent advances brought by genetically modified mice to our understanding of the endogenous composition and role of nAChRs in the nervous system, and of the diverse pharmacological actions of nicotine regarding learning, analgesia, reinforcement, development and aging in the brain will be discussed.
Animals↗
Pretreatment with neurokinin substance P but not with cholecystokinin-8S can alleviate functional deficits of partial nigrostriatal 6-hydroxydopamine lesion.
The neuropeptide substance P (SP) has been implicated in the control of various neuro-behavioral functions including reinforcement and learning processes. It also exerts neurotrophic and regenerating effects in vitro and in vivo. A previous study indicated a potential therapeutic effect of SP in rats with partial 6-hydroxydopamine lesions of the nigrostriatal dopamine system when SP was administered after the lesion. The purpose of the present study was to determine whether prelesion treatment with SP would also interact with the effects of unilateral 6-hydroxydopamine lesion of the substantia nigra. Thus, SP (50 micrograms/kg) was administered i.p. on 8 consecutive days prior to unilateral lesion of the substantia nigra. Furthermore, we investigated the effects of prelesion treatment with cholecystokinin-8S (CCK; 1 microgram/kg), another neuropeptide, which is closely related to dopaminergic neurons, and which also can have neurotrophic and neuroprotective functions. Our results show that animals with partial neostriatal dopamine depletions (residual dopamine levels of more than 10%) did not show turning asymmetries when pretreated with SP, whereas animals pretreated with vehicle exhibited an initial ipsiversive asymmetry from which they recovered. In contrast, behavioral asymmetries were most pronounced in animals which had been pretreated with CCK. These peptide treatments did not affect the degree of neostriatal dopamine depletion; however, dihydroxyphenylacetic acid/dopamine ratios were enhanced in the neurostriatum of animals with partial dopamine damage after SP- and CCK-pretreatment, and in the ventral striatum of SP-pretreated animals. These data provide evidence that prelesion treatment with SP, but not with CCK, can alleviate functional deficits induced by a partial nigro-striatal dopamine lesion. This effect may be related to enhanced ventral striatal dopamine activity and/or to the peptide's known effects on learning, motivation, and emotion.
Animals↗
"Jesus will fix it after awhile": meanings and health.
There are many myths and stereotypes related to the health of people of color in the United States. Many research studies are done and statistics proliferate on the health status of non-dominant groups. Few studies attempt to understand the meaning systems of poor and working class African American women in relationship to health and health care. This study uses an ethnographic approach including narrative analysis of life history interviews in order to examine how the life experiences and belief systems of a small group of poor and working class African American women from a storefront church in Seattle, Washington, inform and influence the women's opinions and interactions with the dominant white health care system. This paper will examine specific dimensions of the women's belief systems and discuss how these beliefs are applied as the women interpret, confront and examine the meaning of health and the meaning of their own experiences in specific health care encounters. The women's belief systems, learned and reinforced within the context of their daily lives, enable the women to offer a unique critique of the health care system, as well as to maintain a powerful subjectivity in the face of an objectifying system, the dominant white western health care system.
Adaptation, Psychological↗
Detecting abuse against women in the home.
Assault is the single major cause of injury to women. Between 1.8 and 4.0 million American women are abused in their homes each year. The perpetrator of domestic violence is usually male (95%), the victim usually female. Most domestic violence is a result of the learning and reinforcement of a power imbalance between partners. Home care providers are in a prime position to detect actual or potential abuse against women, but the dynamics of abuse often produce an artificial home atmosphere, with the occupants ill at ease with the home care provider. This makes detection more difficult. Although a direct inquiry about abuse is usually the best approach, both distinct and subtle signs of abuse can be detected by informed providers. Once physical abuse is detected, it is of paramount importance to select the most appropriate referrals, resources, and strategies to assist the woman in freeing herself of abuse. Emergency departments are recommended for immediate physical treatment, shelters for therapeutic and rehabilitative services.
Community Health Nursing↗
Expression of the c-fos gene in the mouse brain during the acquisition of defensive behavior habits.
Experimental data reported here provide evidence that marked defensive motivation in conditions of an unavoidable electrocutaneous stimulus is accompanied in mice by increases in the expression to the c-fos gene in the hippocampus and cerebral cortex. As reinforcement and learning progress and the animals become able to achieve a useful result--avoiding the electrocutaneous shock--expression of the c-fos gene in these brain structures decreases. The level of expression of the c-fos gene was found to be different in animals in which defensive behavior had different efficacies. Expression was higher in mice making large numbers of errors than in mice with few errors during acquisition of the defensive habit.
Animals↗