Learning and resistance to extinction in external-self dual reinforcement as compared with those in external reinforcement]

Learning and resistance to extinction in external-self dual reinforcement (ESR) were compared with those in external reinforcement (ER). delta ESR (delta: extinction process) was also compared with the corresponding process of other two conditions; 1) discontinuation of self reinforcement after external-self dual reinforcement (delta SR), 2) discontinuation of external reinforcement following the dual reinforcement (delta ER). Undergraduates (n = 58 in Experiment I, n = 74 in Experiment II) were randomly assigned to one of the four conditions. Subjects were given association learning in Exp. I and memory task in Exp. II, respectively. Those who responded successfully were then shifted to extinction session for testing. Effects of ESR on learning were same as those of ER in the two experiments. Resistance to extinction in Exp. I was significantly higher for delta SR and delta ESR as compared with delta ER and *ER (extinction switched from external reinforcement). Resistance for delta SR in Exp. II was significantly higher than for the remaining conditions. Based on these findings, high level of the resistance for delta ESR was discussed by attributing it to the internalization of ESR.     

Amygdaloid complex lesions differentially affect retention of tasks using appetitive and aversive reinforcement

The hypothesis that the amygdaloid complex (AC) is involved in the formation of stimulus-reward associations was examined. A series of experiments (1A-1C) directly compared the effects of lesions (produced by injection of the excitotoxin N-methyl-D-aspartic acid) on 1-trial appetitive and 1-trial aversive learning in rats. Experiments 1A and 1B, which used different degrees of reinforcement, revealed no effect of lesions on the appetitive task, whereas acquisition of the aversive task was significantly impaired. This impairment depended on the nature of the aversive reinforcement used: Impairment was seen when a highly aversive stimulus (footshock) was used but not when a less aversive stimulus (0.2% quinine solution) was used. Control experiments indicated that the effect of lesions was not due to reduced sensitivity to the foot-shock. In Experiment 2, a novel odor conditioning task examined further the effect of AC lesions on the acquisition of appetitive and aversive stimulus-reinforcement associations. As in Experiment 1, the AC lesions impaired learning of the aversive association but did not significantly influence the appetitive association. It is argued that, although the AC may be involved in some types of appetitively rewarded learning, the findings of a differential effect of AC lesions on aversively rewarded learning suggest a role in learning beyond the formation of stimulus-reinforcement associations.     

Sex, beauty and the orbitofrontal cortex.

Face perception is mediated by a distributed neural system in the human brain. Attention, memory and emotion modulate the neural activation evoked by faces, however the effects of gender and sexual orientation are currently unknown. To test whether subjects would respond more to their sexually-preferred faces, we scanned 40 hetero- and homosexual men and women whilst they assessed facial attractiveness. Behaviorally, regardless of their gender and sexual orientation, all subjects similarly rated the attractiveness of both male and female faces. Consistent with our hypothesis, a three-way interaction between stimulus gender, beauty and the sexual preference of the subject was found in the medial orbitofrontal cortex (OFC). In heterosexual women and homosexual men, attractive male faces elicited stronger activation than attractive female faces, whereas in heterosexual men and homosexual women, attractive female faces evoked stronger activation than attractive male faces. These findings suggest that the OFC represents the value of salient sexually-relevant faces, irrespective of their reproductive fitness.     

Adaptive rule learning of event sequences during the A-not-B task in 9-month-old infants

Prior work indicates that infants can use social information to organize simple audiovisual inputs into predictable rules by 8 months of age. However, it is unclear whether infants can use social information to organize more complex events into predictable rules that can be used to guide motor action. To examine these issues, we tested 9-month-old infants using a modified version of an A-not-B task, in which hiding event sequences were paired with different experimenters, who could be used to organize the events into rules that guide action. We predicted that infants’ reaching accuracy would be better when the experimenter changes when the toy's hiding location changes, relative to when the experimenter stays the same, as this should cue a novel rule used to guide action. Experiments 1 and 2 validated this prediction. Experiment 3 showed that reaching accuracy was better when the toy's hiding location switched but was consistent with the rule associated with the experimenter, relative to when the toy's hiding location repeated but was inconsistent with the rule associated with the experimenter. These data suggest that infants can use the identities of experimenters to organize events into predictable rules that guide action in the A-not-B task.     

Gender, social support, and cardiovascular responses to stress

OBJECTIVE: Laboratory research indicates that the presence of a supportive other can reduce physiological responses to a stressor. Whether there are gender differences, either on the part of the provider or the recipient, in this social support effect is explored. Such differences might shed some light on the frequent epidemiological reports of gender differences in social support and health. METHODS: Male and female subjects gave an impromptu speech and received either standardized supportive or nonsupportive feedback from a male or female confederate. Blood pressure and heart rate were monitored continuously during baseline and speech periods. RESULTS: Speakers with a supportive female audience showed a systolic increase of 25 mm Hg over baseline. Those with a nonsupportive female audience increased 36 mm Hg. A supportive male audience led to increases of 32 mm Hg, and a nonsupportive male audience 28 mm Hg. There was no significant effect of gender of subject. CONCLUSIONS: Results indicate that social support provided by women reduced cardiovascular changes for both male and female speakers compared with presence of a nonsupportive female audience. Social support from men did not. These findings suggest a possible mechanism that might help explain the epidemiological literature on the relationship between gender, social support, and health. The findings are consistent with the notion that married men are healthier because they marry women. Women do not profit as much from marriage or suffer as much from separation, in terms of health outcomes, because the support they gain or lose is the less effective support of a man. These findings render more plausible the possibility that differences in social support might contribute to health differences, through the dampening of cardiovascular responses to stress.     

Effects of ability- and chance-determined competition outcome on testosterone

Winning competitions has been shown to lead to higher testosterone (T) relative to losing in men and males of other species. In Experiment 1, 38 women and 37 men provided a saliva sample, completed a novel computer-based vocabulary competition task at which they won or lost based on their own ability, provided feedback about the competition via questionnaire, and then produced a second saliva sample. Task outcome and performance was not sexually differentiated, and overall task performance was negatively correlated with T. Male but not female winners had lower baseline and post-competition T, and male losers had a larger decrease in T from baseline to post-competition. In Experiment 2, 31 men and 43 women completed the same as above, but were randomly assigned to win or lose. In this case, competition outcome did not affect T for men but there was an effect such that women who would have had an ability-determined loss showed a larger decrease in T than women who would have had an ability-determined win. Thus, earned wins appear to attenuate a decline in T in men, consistent with past research into the competition effect and T, and perhaps women under complex circumstances.     

Maternal care affects male and female offspring working memory and stress reactivity

Variations in maternal care affect the development of individual differences in learning and memory and neuroendocrine responses to stress in adult male offspring, but it is not known how variations in maternal care affect adult female offspring. The present study investigated the performance of adult Sprague-Dawley male and female offspring exposed to either low or high levels of maternal licking/grooming on a spatial memory task (Experiment 1) and the effects of acute stress on corticosterone levels and spatial memory performance (Experiment 2). In Experiment 1 rats were trained for 24 days on the spatial working/reference memory version of the radial arm maze (RAM). In Experiment 2, rats were trained on the same RAM task, exposed to an acute stress, and the effect of stress on corticosterone levels and subsequent spatial memory was examined. In Experiment 1, adult female offspring of low licking/grooming dams had enhanced working memory compared to all other groups. In Experiment 2, all groups of male and female offspring had enhanced working memory 24 h after exposure to acute 2 h restraint stress while reference memory was enhanced after stress in male and female offspring of low licking/grooming dams. Furthermore, female offspring of low licking/grooming dams showed the largest corticosterone response to the acute restraint stress compared to all other groups. Male offspring of low licking/grooming dams showed a flattened corticosterone response to stress. Thus variations in maternal care differentially affect working memory and stress reactivity in male and female offspring.     

Concept priming and pain: an experimental approach to understanding gender roles in sex-related pain differences

Prior research has found that sex differences in pain are partially due to individual variations in gender roles. In a laboratory study, we tested the hypothesis that the presence of covert gender role cues can also moderate the extent to which women and men experience pain. Specifically, we varied gender role cues by asking male and female participants to write about instances in which they behaved in a stereotypically feminine, masculine, or neutral manner. Pain and cardiovascular reactivity to the cold pressor task were then assessed. Results revealed that, when primed with femininity, men reported less pain and anxiety from the cold pressor task than women. However, no differences existed between the sexes in the masculine or neutral prime conditions. The results indicate that covert gender cues can alter pain reports. Further, at least in some situations, feminine role cues may be more influential on pain reports than masculine role cues.     

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by ligase chain reaction-based assays with clinical specimens from various sites: implications for diagnostic testing and screening.

Ligase chain reaction (LCR)-based tests for the diagnosis of Chlamydia trachomatis and Neisseria gonorrhoeae infections in men and women attending a sexually transmitted disease clinic were evaluated. LCR testing of urethral swab and urine specimens from men and cervical swab and urine specimens from women was compared with culture of male urethral swabs and female cervical and urethral swabs, respectively. An expanded "gold standard" was defined as a positive culture or at least one specimen confirmed to be positive by LCR testing. The prevalence of C. trachomatis infection as detected by cell culture was 7.0% among 614 men and 5.0% among 602 women. By LCR, these values increased to 11.4 and 9.9% with urethral swabs and urine, respectively, for men and 9.6 and 9.1% with cervical swabs and urine, respectively, for women. Relative to the expanded gold standard, the sensitivity of cell culture with male urethral swabs or female cervical swabs was 57.3 and 45.5%, respectively, compared with corresponding values of 93.3 and 87.9% for LCR. The sensitivity of LCR with urine specimens was 77.3 and 78.8% for men and women, respectively. The prevalence of N. gonorrhoeae infection as detected by culture was 5.9% among 220 men and 2.9% among 383 women. The corresponding values were 8.2 and 5.5%, respectively, by LCR testing of swabs. Prevalence values by LCR testing of urine were 7.3% for men and 2.9% for women. The sensitivity of culture was 72.2% for men and 50.0% for women. The sensitivities of LCR were 100% with male urethral swabs, 95.4% with female cervical swabs, 88.9% with male urine, and 50.0% with female urine. These results indicate that the LCR-based assays represent a major improvement in C. trachomatis and N. gonorrhoeae diagnostics. The sensitivity of testing of urethral or cervical swabs by LCR was markedly greater than that by culture. The sensitivity of testing female or male urine specimens was equal to or greater than that of culturing cervical or urethral specimens. LCR testing of urine specimens may prove useful for screening for C. trachomatis.     

Vulnerability of memory to electroconvulsive shock in relation to onset and offset of reinforcement

Rats displayed amnesia for one-trial aversive (Experiment 1) and appetitive (Experiment 2) learning tasks in which certain durations of continuous exposure to reinforcement were followed immediately by electroconvulsive shock. However, amnesia was significantly attenuated in rats given a shorter exposure to the reinforcement, yet with the same interval between the onset of reinforcement and electroconvulsive shock. Processes that protect newly acquired information from the effects of electroconvulsive shock do not appear to be initiated until the perceived offset of the incoming information flow.     

A neural network model with dopamine-like reinforcement signal that learns a spatial delayed response task.

This study investigated how the simulated response of dopamine neurons to reward-related stimuli could be used as reinforcement signal for learning a spatial delayed response task. Spatial delayed response tasks assess the functions of frontal cortex and basal ganglia in short-term memory, movement preparation and expectation of environmental events. In these tasks, a stimulus appears for a short period at a particular location, and after a delay the subject moves to the location indicated. Dopamine neurons are activated by unpredicted rewards and reward-predicting stimuli, are not influenced by fully predicted rewards, and are depressed by omitted rewards. Thus, they appear to report an error in the prediction of reward, which is the crucial reinforcement term in formal learning theories. Theoretical studies on reinforcement learning have shown that signals similar to dopamine responses can be used as effective teaching signals for learning. A neural network model implementing the temporal difference algorithm was trained to perform a simulated spatial delayed response task. The reinforcement signal was modeled according to the basic characteristics of dopamine responses to novel stimuli, primary rewards and reward-predicting stimuli. A Critic component analogous to dopamine neurons computed a temporal error in the prediction of reinforcement and emitted this signal to an Actor component which mediated the behavioral output. The spatial delayed response task was learned via two subtasks introducing spatial choices and temporal delays, in the same manner as monkeys in the laboratory. In all three tasks, the reinforcement signal of the Critic developed in a similar manner to the responses of natural dopamine neurons in comparable learning situations, and the learning curves of the Actor replicated the progress of learning observed in the animals. Several manipulations demonstrated further the efficacy of the particular characteristics of the dopamine-like reinforcement signal. Omission of reward induced a phasic reduction of the reinforcement signal at the time of the reward and led to extinction of learned actions. A reinforcement signal without prediction error resulted in impaired learning because of perseverative errors. Loss of learned behavior was seen with sustained reductions of the reinforcement signal, a situation in general comparable to the loss of dopamine innervation in Parkinsonian patients and experimentally lesioned animals. The striking similarities in teaching signals and learning behavior between the computational and biological results suggest that dopamine-like reward responses may serve as effective teaching signals for learning behavioral tasks that are typical for primate cognitive behavior, such as spatial delayed responding.     

Androgen and estrogen (α) receptor localization on periaqueductal gray neurons projecting to the rostral ventromedial medulla in the male and female rat

The periaqueductal gray (PAG) is involved in many gonadal steroid-sensitive behaviors, including responsiveness to pain. The PAG projects to the rostral ventromedial medulla (RVM), comprising the primary circuit driving pain inhibition. Morphine administered systemically or directly into the PAG produces greater analgesia in male compared to female rats, while manipulation of gonadal hormones alters morphine potency in both sexes. It is unknown if these alterations are due to steroidal actions on PAG neurons projecting to the RVM. The expression of androgen (AR) and estrogen (ERα) receptors in the PAG of female rats and within this descending inhibitory pathway in both sexes is unknown. The present study used immunohistochemical techniques (1) to map the distribution of AR and ERα across the rostrocaudal axis of the PAG; and (2) to determine whether AR and/or ERα were colocalized on PAG neurons projecting to the RVM in male and female rats. AR and ERα immunoreactive neurons (AR-IR, ERα-IR) were densely distributed within the caudal PAG of male rats, with the majority localized in the lateral/ventrolateral PAG. Females had significantly fewer AR-IR neurons, while the quantity of ERα was comparable between the sexes. In both sexes, approximately 25–50% of AR-IR neurons and 20–50% of ERα-IR neurons were retrogradely labeled. This study provides direct evidence of the expression of steroid receptors in the PAG and the descending pathway driving pain inhibition in both male and female rats and may provide a mechanism whereby gonadal steroids modulate pain and morphine potency.     

The processing of emotional prosody and semantics in schizophrenia: relationship to gender and IQ

BACKGROUND: Female patients with schizophrenia are less impaired in social life than male patients. Because social impairment in schizophrenia has been found to be associated with deficits in emotion recognition, we examined whether the female advantage in processing emotional prosody and semantics is preserved in schizophrenia. METHOD: Forty-eight patients (25 males, 23 females) and 46 controls (23 males, 23 females) were assessed using an emotional language task (in which healthy women generally outperform healthy men), consisting of 96 sentences in four conditions: (1) neutral-content/emotional-tone (happy, sad, angry or anxious); (2) neutral-tone/emotional-content; (3) emotional-tone/incongruous emotional-content; and (4) emotional-content/incongruous emotional-tone. Participants had to ignore the emotional-content in the third condition and the emotional-tone in the fourth condition. In addition, participants were assessed with a visuospatial task (in which healthy men typically excel). Correlation coefficients were computed for associations between emotional language data, visuospatial data, IQ measures and patient variables. RESULTS: Overall, on the emotional language task, patients made more errors than control subjects, and women outperformed men across diagnostic groups. Controlling for IQ revealed a significant effect on task performance in all groups, especially in the incongruent tasks. On the rotation task, healthy men outperformed healthy women, but male patients, female patients and female controls obtained similar scores. CONCLUSION: The advantage in emotional prosodic and semantic processing in healthy women is preserved in schizophrenia, whereas the male advantage in visuospatial processing is lost. These findings may explain, in part, why social functioning is less compromised in women with schizophrenia than in men.     

The influence of social support on cardiovascular responses during stressor anticipation and active coping

This study investigated effects of different types of social support on cardiovascular reactivity during anticipation of, performance of and recovery from an evaluative speaking task. Thirty male and 30 female students were assigned to one of three social conditions: alone, mental activation of supportive ties, actual support transactions. Cardiovascular effects of social support were found to differ over task conditions and they were not unidirectional. During passive stressor anticipation, support conditions attenuated SBP reactivity, in particular mental activation of supportive ties. During active speech performance gender-specific support effects were observed. The alone condition elicited higher SBP reactivity in men compared to women, support conditions enhanced SBP reactivity in women and attenuated SBP reactivity in men resulting in comparable cardiovascular activation across gender groups. Drawing from research on active coping and energization gender-specific cardiovascular activation was attributed to differences in effort expenditure.     

Comparing gender awareness in Dutch and Swedish first-year medical students - results from a questionaire

Background  

To ascertain good and appropriate healthcare for both women and men implementation of gender perspectives in medical education is needed. For a successful implementation, knowledge about students' attitudes and beliefs about men, women, and gender is crucial. The aim of this study was to compare attitudes to gender and gender stereotyping among Dutch and Swedish male and female medical students.     

EXPERIMENTER EFFECTS ON THE PHYSIOLOGICAL EXPERIMENT

Human subjects establish expectancies that often reflect the investigator's orientation before and during an experiment. The purpose of this experiment is to determine the effects of subject expectancies as inadvertently influenced by the investigator in a perceptual-physiological experiment, even to the point where the principal investigator's choice of an “experimentally naive” assistant still reflects his expectancies. Eighteen adult male subjects were randomly assigned to one of three different naive experimenters: (1) an automated procedure, (2) a reserved female, and (3) a sociable female. All the subjects were tachistoscopically presented with 76 four-letter words which included both socially acceptable and taboo words. The subjects' physiological responses were monitored during the entire experiment. The words were grouped according to their social desirability and were analyzed by a trend analysis of variance. The results demonstrate that both the subject's physiological responsivity and his reporting of socially acceptable and taboo words are dependent upon the experimenter.     

Comparison of factor-analyzed Adolescent Reinforcement Survey Schedule (ARSS) responses from Japanese and American adolescents.

The Adolescent Reinforcement Survey Schedule (ARSS) was administered to a sample of male and female late adolescent college students from Japan (N = 500). The responses to the ARSS are factor analyzed using a principal component method. The results of the factor-analyzed ARSS from the Japanese sample are compared and contrasted with the results from a previous study (Holmes et al., 1987) in which ARSS was administered to a sample of American male and female college students (N = 231). Both the American and Japanese samples produced 10 interpretable factors. A recommendation is made to replicate the present study with groups of early and mid-adolescents in each culture in order to study shifts in reinforcers during different periods of adolescent development.     

The associations of gender, sexual identity and competing needs with healthcare utilization among people with HIV/AIDS

Studies report gender differences in medical service utilization among persons with HIV, although most compare women to heterogeneous groups of men. Competing needs for medical care of women may contribute to those differences. We examined prospectively the role that competing social, economic and health needs, such as caring for others, play in gender differences in hospital, ambulatory and emergency room (ER) visits. We considered sexual identity to study women, gay/bisexual men and heterosexual men in the most recent wave (n = 1,385) of the HCSUS, a nationally representative sample of persons with HIV/AIDS in care in the United States. We considered gay/bisexual men and heterosexual men separately because their different resources and social networks may lead to disparate service utilization. Multivariate regression showed that women were more likely than gay/bisexual men to be hospitalized, while women and gay/bisexual men were more likely than heterosexual men to use the ER without subsequent hospitalization. Controlling for competing needs eliminated neither difference but predicted hospitalization and ER use. Findings suggest that addressing competing needs could reduce unnecessary hospitalization and ER use for both genders. Furthermore, examinations of gender differences in service use should include sexual identity.