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PubMed1969

Persistent shock-elicited responding engendered by a negative-reinforcement procedure.

A procedure in which responses reduced intermittently presented electric shocks to one quarter of their originally scheduled intensity, effectively engendered and maintained lever pressing in hooded rats. This contingency also markedly increased the response rates of rats initially trained under an unsignaled avoidance procedure. The responding of all animals extinguished rapidly when shock was withdrawn. Subsequently, it was discovered that high response rates could be maintained solely through presentation of shocks that were not affected by responses. Variations in the interval between shocks and changes in shock intensity over a wide range did not attenuate responding. Terminal performance was characterized by a consistent pattern of shock-elicited responses. Responses were also elicited by a tone following repeated tone-shock pairings. Finally, responding that was maintained by response-independent shocks was quickly suppressed by response-contingent shocks of the same intensity.

Journal Article↗
PubMed2004

Individual differences in sensitivity to factors provoking reinstatement of cocaine-seeking behavior.

Among cocaine addicts, there is a strong variation in response to relapse provoking factors like conditioned cues and renewed contact with the drug. Here we show that such large individual differences also exist in rats. Reinstatement of extinguished cocaine-seeking behavior was triggered by contingent presentation of a cocaine-conditioned cue or an amphetamine priming injection. We found no positive correlation between cue- and drug-controlled reinstatement of cocaine seeking. Rather, a slight, but significant negative correlation was observed, which was particularly evident in two subgroups of rats that responded highest following either amphetamine priming or cue presentation. A large middle group responded equally for both relapse provoking factors. Further, cocaine-seeking behavior during the first extinction session correlated positively with cue-induced reinstatement. In conclusion, the present findings indicate that the therapeutic efficacy of relapse prevention strategies may depend on individual sensitivity to distinct relapse provoking stimuli.

Amphetamine↗
PubMed1976

Dependence of reward contingent positive variation (RCPV) and cortical synchronization on visual input in the cat.

Cats trained to press a lever for milk reward display high amplitude low frequency electrocorticographic post-reinforcement synchronization (PRS) associated with epicortical steady potential shift, termed Reward Contingent Positive Variation (RCPV), over the parieto-occipital cortex. Previously, it was found that the PRS-RCPV phenomenon depends on unpatterned light input devoid of any conceivable information or conditional property. Although training in the dark most likely eliminated the "novelty" factor and the resulting orienting reaction to "light off" as a cause of PRS-RCPV suppression, a possibility could not be excluded that the absence of light had a negatively reinforcing property preventing the emergence of PRS-RCPV. Hence, in the present study an experimental paradigm was used in which "light off" and/or "tone on" cues signalled the availability of reward, the "light off" periods extending through the consummatory response. Seven out of 9 cats, despite 2-4 months of daily training, and 85% correct timing of bar press performance, never showed a PRS-RCPV response (one animal showed only sporadic and poorly developed patterns.) However, when the light was turned on during consumption, in 85% of such tests a fully developed PRS-RCPV emerged in a stimulus-bound manner. One animal was an exception and showed PRS-RCPV both in the absence and presence of light. It was concluded that light input plays a crucial role in the emergence of the PRS-RCPV phenomenon and therefore also participates in the integration of gustatory input.

Animals↗
PubMed1992

Environmental and social determinants of sexual function in the male lesser mouse lemur (Microcebus murinus).

Environmental factors that regulate the sexual activity of male lesser mouse lemurs have been studied experimentally with more than 60 captive animals over an 8-year period. In this nocturnal Malagasy prosimian, variation in day length is the primary factor controlling seasonal sexual activity. Plasma testosterone concentrations were low (= 9 ng/ml) during short days and reached 60 ng/ml during long days (> 12-hour day). This cyclic pattern persists unchanged when artificial photoperiodic rhythms are applied and is not altered by ageing. The timing of puberty is also regulated by photoperiodic changes. Nevertheless, the sexual activity of the male lesser mouse lemur can be dramatically modified by the social environment. In heterosexual groups, behavioural and physiological components of sexual activity are depressed in all males except the dominant one, whose aggressive interactions are always successful. Intermale sexual inhibition was shown to be mediated by chemical cues present in the urine of dominant or isolated males but not in urine of subordinate individuals. The inhibitory signals possess lipophilic properties and are not contingent on the gonadal activity of the urine donor but are linked to adrenocortical activity. By contrast, chemical signals stimulating the reproductive function of all males are found in the urine of females, the presence of which is required for the establishment of clear dominance among grouped males. Endocrine mechanisms underlying intermale sexual inhibition by chemical cues were analysed. Variations in prolactin strongly suggest that olfaction interacts with the photoperiodic regulation of reproductive function, leading to changes in the sensitivity of the negative feedback effect of testosterone on gonadotrophin secretion. Inhibitory or stimulatory effects of chemical signals are discussed in the context of their functional significance for wild populations.

Aggression↗
PubMed2005

Association analysis of CHMP1.5 genetic variation and bipolar disorder.

OBJECTIVES: The18p11.2 region surrounding the G-olf gene has been linked in several independent studies to bipolar disorder and schizophrenia, yet association studies between G-olf genetic variations and bipolar disorder have been negative. We hypothesized that the linkage in this region might be due to a gene in close physical proximity to G-olf, and we examined variations in the CHMP1.5 gene within intron 5 of G-olf for association with bipolar disorder. METHODS: Two single-nucleotide polymorphisms, rs1786581 and rs1249624, were analyzed for association with bipolar disorder in 402 unrelated bipolar individuals and 181 unrelated controls. Genotyping was performed via pyrosequencing and restriction fragment length polymorphism analysis; results were compared by chi2 contingency analysis. RESULTS: No evidence was found for association of either allele at rs1249624 with bipolar disorder (chi2=1.25, degrees of freedom=1, P=0.26); however, a trend towards association with the 'T' allele at rs1786581 and with the 'T/T' 1786581/1249624 haplotype was observed. The chi2 for the haplotype was 7.16, (degrees of freedom=3, P=0.067) and for rs1786581 chi2=3.56, degrees of freedom=1, P=0.060; these differences are not statistically significant. CONCLUSIONS: Variation in the CHMP1.5 gene does not appear to be associated with bipolar disorder. A systematic assessment of genetic variation in the region using association studies will be necessary.

3' Untranslated Regions↗
PubMed2004

Stability and change in perception: spatial organization in temporal context.

Perceptual multistability has often been explained using the concepts of adaptation and hysteresis. In this paper we show that effects that would typically be accounted for by adaptation and hysteresis can be explained without assuming the existence of dedicated mechanisms for adaptation and hysteresis. Instead, our data suggest that perceptual multistability reveals lasting states of the visual system rather than changes in the system caused by stimulation. We presented observers with two successive multistable stimuli and found that the probability that they saw the favored organization in the first stimulus was inversely related to the probability that they saw the same organization in the second. This pattern of negative contingency is orientation-tuned and occurs no matter whether the observer had or had not seen the favored organization in the first stimulus. This adaptation-like effect of negative contingency combines multiplicatively with a hysteresis-like effect that increases the likelihood of the just-perceived organization. Both effects are consistent with a probabilistic model in which perception depends on an orientation-tuned intrinsic bias that slowly (and stochastically) changes its orientation tuning over time.

Adaptation, Physiological↗
PubMed2001

Clinical features of latent inhibition in schizophrenia.

Paradigms of Latent Inhibition (LI) are inter-species and derived from learning theories. They are considered as tools which allow the attentional processes to be studied. The absence of LI is interpreted as difficulty in discriminating relevant and irrelevant stimuli. Abolition of LI has been shown in acute schizophrenics. The objectives of our study were partly to validate an LI paradigm, based on a contingency detection between two stimuli, in healthy subjects, and partly to analyse LI in schizophrenics. The study included 105 subjects (65 patients and 40 controls). Patients fulfilled the DSM IV diagnosis of schizophrenia. 35 in the acute phase and 30 in the chronic phase. We observed a loss of LI for acute schizophrenics, and an enhancement of LI for chronic schizophrenics. The variations in LI are interpreted from the perspective of a disturbance in the attentional processes. The LI status in acute schizophrenics appears to correlate with the clinical criteria with a prognostic value (low intensity of the negative dimension, late age at the first hospitalization). Moreover, the enhancement of LI correlates with the negative dimension of schizophrenic disease. This correlation is found in acute and chronic schizophrenics. It suggests that the variations of LI may be an indicator of adaptive strategies to a cognitive dysfunction specific to schizophrenia.

Adult↗
PubMed2000

The equivalence of contingency structure for intuitive covariation judgments about height, weight, and body fat.

In a complete between-subjects design, 576 respondents judged covariations of problems framed around height, weight, and body fat. A verbal measure was used, consisting of propositional statements representing relationships between two of the variables, as well as two types of response options: true or false, and a 7-point, bipolar, Likert-type scale. Consistent with previous findings, weight and body fat were unambiguously judged as if positively correlated; there were indications of a perceived negative correlation of height and body fat; and there was no evidence that participants regarded height and weight as positively correlated. Furthermore, there was no reliable evidence in support of framing effects. However, there were indications of influence for conditional format. These findings are discussed relative to previous and ongoing research efforts, and it is concluded that it may be inappropriate to regard variations in conditional format as parallel items. Measures involving all possible variations are considered fundamentally unbiased and consistent with I. Ajzen's (1988) principle of aggregation.

Adult↗
PubMed2006

Body image and children's mental health related behaviors: results from the healthy passages study.

OBJECTIVE: This study examined the relationship between body image discrepancy (BID) scores for actual versus ideal body image for children and indicators of child mental health. METHODS: Data were collected from 650 5th graders and their parents who participated in the Healthy Passages Phase I study. Participants were recruited through schools in Alabama, California, and Texas. Measures included the Collins Body Image to produce child- and parent-reported child BID scores, respectively, body mass index (BMI) for child and parent, the Strengths and Difficulties Questionnaire (SDQ), and the Positive and Negative Affect Scale for Children (PANAS-C). RESULTS: After controlling for potential confounders, children's internalizing problems as rated by parents and negative affect as rated by children were significantly associated with discrepancies based on child- and parent-reported child BID scores, respectively. CONCLUSIONS: Overall, higher child- and parent-reported child BID scores were significantly associated with more internalizing problems and negative affect among children. There were some inconsistencies in the associations between other mental health behaviors and child BID scores contingent on parent or child ratings. Early intervention may be indicated to prevent possible adverse consequences, especially for internalizing problems, from the effects of child- and parent-reported child BID scores on adolescent and adult mental health and well-being.

Body Image↗
PubMed1991

Judging social issues: difficulties, inconsistencies, and consistencies.

The three studies reported in this Monograph examine high school and college students' reasoning about the issues of abortion, homosexuality, pornography, and incest. The studies stemmed from previous research on reasoning in the "prototypical" moral, social conventional, and personal domains. We postulated that abortion, homosexuality, pornography, and incest are nonprototypical issues. We expected that reasoning about nonprototypical and prototypical issues would differ and that reasoning about nonprototypical issues would be inconsistent and involve ambiguities in informational assumptions. Two groups were preselected in Study 1, those who negatively and those who positively evaluated the nonprototypical issues. Assessments were made of criterion judgments (evaluations, rule contingency, and generalizability) and justifications regarding moral, personal, and nonprototypical issues. The groups differed in judgments about the nonprototypical issues but not the moral issues. Both groups gave noncontigent and generalized judgments about moral issues, with justifications of justice and rights. Subjects who evaluated nonprototypical acts negatively used varied and often inconsistent configurations of criterion judgments. Responses coded for general reasoning types often entailed juxtapositions of prescriptive judgments and assertions of personal choice. Subjects who evaluated nonprototypical acts positively judged that they should be legal and nongeneralized and gave justifications based on personal choice. Using similar procedures, Study 2 was conducted with practicing Catholics attending parochial high schools. The findings paralleled those of Study 1, including a split among subjects in their evaluations of the nonprototypical issues. The results suggested a bidirectional relation between individual judgments and group positions. The findings of Studies 1 and 2 suggested that variations in evaluations and judgments about the nonprototypical issues were associated with variations in ambiguously held informational assumptions. Study 3 examined the role of such informational assumptions. It was found that assumptions associated with judgments about abortion and homosexuality were ambiguous and inconsistently applied. Thus, we propose that ambiguity around assumptions is a central component of the nonprototypicality of these issues.

Abortion, Legal↗
PubMed2004

Variations in evidence-based clinical practices in nine United States Veterans Administration opioid agonist therapy clinics.

BACKGROUND: Opioid agonist therapy (OAT) for opioid dependence has a strong evidence base, but clinical practice often does not conform to evidence-based practices. The goal of the OpiATE Initiative is to improve patient outcomes by implementing four evidence-based practices in United States Veterans Administration OAT clinics: (1) long-term maintenance orientation, (2) adequate dosing, (3) adequate counseling, and (4) use of contingency management. METHODS: The OpiATE monitoring system (OMS) was developed to help clinics assess concordance with evidence-based practices. For each patient, counselors record current agonist dose, recent counseling frequency, length of treatment, and urine toxicology results. For patients with sub-standard agonist doses, an algorithm was used to determine if the current dose was clinically appropriate. Maintenance orientation was assessed using the abstinence orientation scale. RESULTS: Concordance with counseling recommendations was uniformly high, concordance with maintenance orientation and dosing recommendations varied widely across clinics, and concordance with contingency management principles was low. Abstinence orientation scores were negatively correlated with dose and patient retention. Dose was negatively correlated with percent of urine screens positive for non-medical opioids and other illicit substances. CONCLUSIONS: The OMS was well accepted by clinic staff. Wide variability in clinical practices and outcomes across clinics supports the importance of individualizing quality improvement strategies to address specific performance gaps.

Analgesics, Opioid↗
PubMed2005

Adults with autism living at home or in non-family settings: positive and negative aspects of residential status.

BACKGROUND: Very little is known about the context of caregiving by parents of adults with autism or about the perceived impacts of continued patterns of co-residence vs. out-of-family living. In the present study, maternal assessments of residential status, involvement with adult children living in a non-family setting, and the impacts on mothers of their residential arrangements were examined. METHODS: Mothers from 133 families of adults (aged 22 years and older) with autism spectrum disorder (ASD) completed questionnaires as part of a longitudinal study on family caregiving. Mothers completed open-ended questions regarding the positive and negative aspects of their child's residential arrangement. Mothers also completed scaled questions regarding their satisfaction with their child's residential arrangement, the different ways in which people's lives change after a relative moves from the home, and the frequency of contact with their son or daughter. RESULTS: Mothers found co-residing with their adult child to be of greatest positive benefit to the family while those living apart found this residential arrangement of greatest benefit to the son or daughter with ASD. The greatest negative consequences for co-residing mothers were understood to fall on families, while mothers felt the majority of negative consequences for those that lived apart. There was a high level of contact and maternal involvement between the mother and adult child with ASD even after out-of-home placement. CONCLUSIONS: Residential status, as appraised by mothers, has varying impacts on the individual with ASD, on the family, and on mothers as individuals and caregivers. The present analysis suggests the multifaceted and highly contingent maternal experience associated with where her child with ASD lives. Among families whose children live elsewhere, there is an impressive amount of continued contact between these families and their son/daughter.

Adolescent↗
PubMed1998

Genome evolution within the alpha Proteobacteria: why do some bacteria not possess plasmids and others exhibit more than one different chromosome?

Animal intracellular Proteobacteria of the alpha subclass without plasmids and containing one or more chromosomes are phylogenetically entwined with opportunistic, plant-associated, chemoautotrophic and photosynthetic alpha Proteobacteria possessing one or more chromosomes and plasmids. Local variations in open environments, such as soil, water, manure, gut systems and the external surfaces of plants and animals, may have selected alpha Proteobacteria with extensive metabolic alternatives, broad genetic diversity, and more flexible and larger genomes with ability for horizontal gene flux. On the contrary, the constant and isolated animal cellular milieu selected heterotrophic alpha Proteobacteria with smaller genomes without plasmids and reduced genetic diversity as compared to their plant-associated and phototrophic relatives. The characteristics and genome sizes in the extant species suggest that a second chromosome could have evolved from megaplasmids which acquired housekeeping genes. Consequently, the genomes of the animal cell-associated Proteobacteria evolved through reductions of the larger genomes of chemoautotrophic ancestors and became rich in adenosine and thymidine, as compared to the genomes of their ancestors. Genome organisation and phylogenetic ancestor-descendent relationships between extant bacteria of closely related genera and within the same monophyletic genus and species suggest that some strains have undergone transition from two chromosomes to a single replicon. It is proposed that as long as the essential information is correctly expressed, the presence of one or more chromosomes within the same genus or species is the result of contingency. Genetic drift in clonal bacteria, such as animal cell-associated alpha Proteobacteria, would depend almost exclusively on mutation and internal genetic rearrangement processes. Alternatively, genomic variations in reticulate bacteria, such as many intestinal and plant cell-associated Proteobacteria, will depend not only on these processes, but also on their genetic interactions with other bacterial strains. Common pathogenic domains necessary for the invasion and survival in association with cells have been preserved in the chromosomes of the animal and plant-associated alpha Proteobacteria. These pathogenic domains have been maintained by vertical inherence, extensively ameliorated to match the chromosome G + C content and evolved within chromosomes of alpha Proteobacteria.

Animals↗
PubMedDate not supplied

Psychological androgyny and preference for intubation in a hypothetical case of end-stage lung disease.

Psychological androgyny theory (PAT) was employed as a model of the interpersonal (social) and task activities required of physicians for care of their patients. According to PAT, individuals with a large repertoire of task and social skills ("androgynous" individuals) should be optimally adaptable to contingencies reflecting varying combinations of task and social challenges. The authors examined the relationship between androgyny and preference for intubation on a patient management problem involving end-stage lung disease for 67 general internists and internal medicine housestaff from two hospitals. Results revealed a negative relationship between androgyny and preference for intubation, suggesting that androgynous and nonandrogynous physicians respond differently to complex and difficult decision-making tasks. Indirect evidence is offered to suggest that this response reflects a general tendency to utilize fewer health care resources. Discussion focuses on the need to improve the precision of measurement of these latent constructs.

Extraversion, Psychological↗
PubMed1992

Effect of a means-end contingency on young children's food preferences.

This study showed that a means-end relationship between two snacks exerts a negative influence on preference for the means snack in the contingency. Two snacks ranked of approximately equal medium appeal were individually chosen from an array by each of 86 children (ages 4 years, 4 months to 7 years, 2 months). Children were then assigned to a means-end condition (where one snack was eaten as a means of gaining the other), a temporal order control group (where one snack was presented and eaten before the other), or a mere exposure control group (where the children chose the order in which they ate the two snacks). Post-treatment rankings of the snacks showed that children in the means-end group came to devalue the means snack relative to the reward snack, despite the demonstrably equal prior appeal of the two snacks. Children in the temporal order and mere exposure control groups did not come to prefer the two snacks preferentially. Implications of the finding that adults can affect children's preferences by relatively minor variations in the manner of presentation are discussed.

Adolescent↗
PubMed2003

[Responses of interspecific relationships among main herbaceous plants to flooding disturbance in Songnen Plain, northeastern China].

To investigate the effects of flooding disturbance on the interspecific relationships among grassland plant species, a comparatively thorough study was conducted on Sanjiadian National Rangeland in the territory of Da'an city, Jilin Province, which was partly flooded in 1998. The study site was located in the south of Songnen plain, Northeastern China, dominated by Leymus chinensis grassland. Along the flooding gradients (from un-flooded to heavily flooded) formed on an extensive mild slope taken as the test site, four flooded transects coded T1, T2, T3 and T4 respectively, but subjected to the flood of different durations were designed, and also an un-flooded one coded T0 was set as a control at relatively higher elevation. Before flooding occurred in 1998, the slope had almost uniform soil and L. chinensis dominated vegetation. Contingency table was used to calculate the interspecific association indice, while Spearman rank correlation coefficient was adopted to analyze the interspecific covariance. The results showed that flooding disturbance had little effect on the association type for most species pairs, but had some effect on the rank coefficients of inter-specific co-variation. Different species pairs varied greatly in their responses to the flooding disturbance, suggesting that the inter-specific co-varying relations were not only dependent on environmental perturbation or disturbance factors, but also on (probably to a larger extent) the biological & ecological properties of the species that comprised the species pairs. The interspecific association types that could be determined between Potentilla paradoxa and all the other plant species were always positive, and little affected by flooding disturbance. As a main companion species, P. paradoxa had a broad ecological breadth, and weak selectivity for habitat. Contrarily, the interspecific association types that could be determined between Phragmites australis and others plant species (in addition to Scirpus planiculmis) were always negative, probably due to the biological properties of the plant. P. australis was a kind of clonal plant with long rhizomes, and enlarge its population through vegetative propagation by rhizomes. When in good water conditions, P. australis had a powerful competitive ability, thereby, imposed competitive or exclusive effects on the other plant species, thus formed the negative correlations between the plant and the other, which could be little affected by flooding disturbance. Interspecific covariance was not only influenced by environmental or disturbance factors, but also dependent on the different responses to the changing environments during the disturbances between the component species that comprised the species pairs. The two plant species that had similar and dissimilar water demands would tended to be positive and negative covariance respectively, if water conditions changed towards an extreme. Interspecific covariance based on the numerical properties of the communities were much more sensitive to the external disturbance than the interspecific associations calculated only based on the binary data of "presence or absence of species".

Disasters↗
PubMed1996

Diagnostic serologic testing of cage and aviary birds for chlamydiosis and suggested confirmatory testing.

A 2 x 2 contingency table was constructed to demonstrate the relationships between detectable chlamydial antibody activity and clinical health status of tested birds. The table revealed that 65.5% of clinically ill birds were antibody positive by elementary body agglutination (EBA) (> or = 10 titers) and 59.0% were antibody positive by latex agglutination (LA). Thus, EBA was slightly more sensitive than LA in detecting antibody activity. Of the clinically normal birds, 96.7% were antibody negative (< 10 titers) by EBA and 98.3% were antibody negative by LA. Individual serum or plasma samples from a group of mixed types of psittacine birds and cockatiels were tested as a separate group, and relationships between EBA-detectable antibody activity and health status were obtained from a 2 x 2 contingency table. Sixty-six percent of birds clinically ill with signs of chlamydiosis in the mixed-type group were antibody positive, whereas only 32.3% of clinically ill cockatiels were antibody positive. Statistical analysis of the contingency table using a chi-square test demonstrated that the EBA test differentiates between individual birds on the basis of health status (P < 0.001). When testing paired serum or plasma samples by EBA, LA, and direct complement fixation (DCF), the highest percentage of significant (> or =4-fold change) titer decreases was detected by LA, and the highest percentage of significant titer increases was detected by DCF. Examples of EBA, LA, and DCF titers in paired and multiple serum or plasma samples are presented to show the variety of responses that can occur. Results reflected variations seen in individual testing of birds with titer variability seen in the first sample tested. Additional types of testing believed necessary for confirming or ruling out an infectious process in birds are outlined. The current interpretations of serologic results are given.

Agglutination Tests↗
PubMedDate not supplied

Extracellular dopamine in the rat prefrontal cortex during reward-, punishment- and novelty-associated behaviour. Effects of diazepam.

Variations of extracellular dopamine (DA(ext)) levels in prefrontal cortex were assessed by in vivo microdialysis. In rats trained in an operant fixed interval (FI(30s)) schedule of food delivery, acute exposure to contingent foot shocks resulted in a suppression of responding that was reversed by diazepam (4 mg/kg, ip). No changes in cortical DA(ext) levels occurred during this period in both control and treated rats. By contrast, in control rats, cortical DA(ext) levels increased (+25-40%) during the nonpunished component of the operant session, and during noncontingent food delivery (+25%). Control rats placed into an unfamiliar brightly lit openfield exhibited a marked increase in cortical DA(ext) levels (+100%). This effect occurred neither in rats given diazepam at a dose (2 mg/kg) which stimulated motor activity, nor during a second exposure to the openfield. In conclusion, a benzodiazepine-sensitive activation of mesoprefrontal DA neurones is induced by exposure to novel stressful surroundings and by food availability and consumption. The fact that cortical DA(ext) levels remained unchanged in rats that exerted complete control upon negative stimuli indicates that an activation of the mesoprefrontal DA system is not required for punishment-induced behavioural blockade.

Animals↗